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Gliclazide metabolism is mediated by genetically polymorphic CYP2C9 and CYP2C19 enzymes. We investigated the effects of CYP2C9 and CYP2C19 genetic polymorphisms on the pharmacokinetics and pharmacodynamics of gliclazide. Twenty-seven Korean healthy volunteers were administered a single oral dose of gliclazide 80 mg. The plasma concentration of gliclazide was quantified for the pharmacokinetic analysis and plasma concentrations of glucose and insulin were measured as pharmacodynamic parameters. The pharmacokinetics of gliclazide showed a significant difference according to the number of defective alleles of combined CYP2C9 and CYP2C19. The two defective alleles group (group 3) and one defective allele group (group 2) showed 2.34- and 1.46-fold higher AUC 0-∞ (P < 0.001), and 57.1 and 32.3% lower CL/F (P < 0.001), compared to those of the no defective allele group (group 1), respectively. The CYP2C9IM-CYP2C19IM group had AUC 0-∞ increase of 1.49-fold (P < 0.05) and CL/F decrease by 29.9% (P < 0.01), compared with the CYP2C9 Normal Metabolizer (CYP2C9NM)-CYP2C19IM group. The CYP2C9NM-CYP2C19PM group and CYP2C9NM-CYP2C19IM group showed 2.41- and 1.51-fold higher AUC 0-∞ (P < 0.001), and 59.6 and 35.4% lower CL/F (P < 0.001), compared to those of the CYP2C9NM-CYP2C19NM group, respectively. The results represented that CYP2C9 and CYP2C19 genetic polymorphisms significantly affected the pharmacokinetics of gliclazide. Although the genetic polymorphism of CYP2C19 had a greater effect on the pharmacokinetics of gliclazide, the genetic polymorphism of CYP2C9 also had a significant effect. On the other hand, plasma glucose and insulin responses to gliclazide were not significantly affected by the CYP2C9-CYP2C19 genotypes, requiring further well-controlled studies with long-term dosing of gliclazide in diabetic patients., (© 2023. The Pharmaceutical Society of Korea.)

Background: Numerous herbs are reported to have anti-hyperglycemic activity and are frequently used in combination with prescription drugs to lower the blood glucose levels in diabetic patients, without proper knowledge about the possibility of herb-drug interaction., Objectives: To investigate the effect of cumin and garden cress on pharmacokinetics (PK) and pharmacodynamics (PD) of gliclazide (GLZ) in nicotinamide-streptozotocin diabetic model., Methods: Diabetic animals of groups II-IV were treated with GLZ, cumin, 'cumin + GLZ', garden cress and 'garden cress + GLZ'. Herb's treatments were given for two weeks, and GLZ was administered in a single dose. Blood glucose levels (BGLs) were measured at pre-determined time points. Plasma samples of pharmacokinetic study were analyzed using UPLC-MS/MS. GLZ fragment at m/z 324.1>127 was monitored., Results: Cumin and garden cress have shown 15.3% and 15.9% reduction in mean BGL (1-24h) (p-value < 0.001), respectively. GLZ reduced mean BGL by 30.0%, which was significantly better than cumin and garden cress (pvalue <0.05). Concurrently administered "garden cress + GLZ" demonstrated the highest reduction in mean BGL (by 40.46%) and showed a prolonged effect. There was no significant advantage of simultaneously administered 'cumin + GLZ'. Cumin did not affect PK of GLZ. Garden cress has significantly enhanced AUC 0-t (by 69.8%, pvalue 0.0013), but other PK parameters C max , T max , and Kel were close to the control group., Conclusion: PK/PD-based herb-drug interaction was observed. Concurrently administered garden cress + GLZ showed improved antidiabetic effect and has enhanced GLZ bioavailability., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Nigella sativa oil (NSO) has been used widely for its putative anti-hyperglycemic activity. However, little is known about its potential effect on the pharmacokinetics and pharmacodynamics of antidiabetic drugs, including gliclazide. This study aimed to investigate herb-drug interactions between gliclazide and NSO in rats. Plasma concentrations of gliclazide (single oral and intravenous dose of 33 and 26.4 mg/kg, respectively) in the presence and absence of co-administration with NSO (52 mg/kg per oral) were quantified in healthy and insulin resistant rats (n = 5 for each group). Physiological and treatment-related factors were evaluated as potential influential covariates using a population pharmacokinetic modeling approach (NONMEM version 7.4). Clearance, volume of distribution and bioavailability of gliclazide were unaffected by disease state (healthy or insulin resistant). The concomitant administration of NSO resulted in higher systemic exposures of gliclazide by modulating bioavailability (29% increase) and clearance (20% decrease) of the drug. A model-independent analysis highlighted that pre-treatment with NSO in healthy rats was associated with a higher glucose lowering effect by up to 50% compared with that of gliclazide monotherapy, but not of insulin resistant rats. Although a similar trend in glucose reductions was not observed in insulin resistant rats, co-administration of NSO improved the sensitivity to insulin of this rat population. Natural product-drug interaction between gliclazide and NSO merits further evaluation of its clinical importance., (© 2021 John Wiley & Sons Ltd.)

In vitro and in vivo studies of gliclazide (GLZ)-loaded freeze-dried alginate-gelatin (AL-GL) beads were carried out, aiming to modify its oral bioavailability. Crosslinked freeze-dried GLZ AL-GL beads (particle size: 1.5- and 3.0-mm) were prepared. In vitro evaluation of GLZ AL-GL beads included SEM, DSC, FT-IR, and release rate study in gradient media. In vivo study was single-dose (4 mg/kg), randomized, parallel-group design, two-treatment (T: test GLZ AL-GL beads and R: reference product Diamicron® 30-mg MR tablet) conducted in 96 healthy rats. Each group was subdivided into 2 sub-groups (G1 and G2) having different blood sampling schemes for up to 72 h. Assessment of level A in-vitro-in-vivo correlation (IVIVC) model was carried out. AL-GL beads successfully increased GLZ release rate compared to R. GLZ percent released (Q 4h ) was 109.34, 86.85, and 43.43% for 1.5-mm and 3.0-mm beads and R, respectively. DSC analysis confirmed the interaction of AL-GL via crosslinking. No chemical interaction of GLZ has occurred as proved by FT-IR. Relative bioavailability (T/R) for AUC 0-∞ was 132.45% for G1 and 146.16% for G2. No significant differences between T and R in the primary pharmacokinetic parameters were determined. T max values were found to be earlier in the case of G1 than those of G2. A secondary absorption peak of GLZ was clearly detected in the case of R while its sharpness was minimized in T. High IVIVC was established, and hence, the proposed in vitro release model perfectly correlated with the in vivo study. The current study design might be a platform to enable panoramic view for GLZ variability in vivo.

A simple and reliable high-performance liquid chromatography method for simultaneous quantitation of gliclazide and ciprofloxacin in plasma sample has been developed and validated. This method implements protein precipitation, a simple and practical pretreatment method by the addition of acetonitrile that gives a clean supernatant. The separation was carried out in a system consisted of a C18 column with acetonitrile and KH2PO4 (0.01 M, 0.1% v/v of triethylamine, pH 2.7) as the mobile phase in a gradient elution at a total flow-rate of 1 mL/min. Gliclazide and ciprofloxacin were quantitated using an ultraviolet detector set at wavelengths of 229 and 277 nm, respectively, which ensures optimal sensitivity for both compounds. This method possesses an excellent linearity at concentration ranges of 0.5-50 mg/L for gliclazide and 0.1-10 mg/L for ciprofloxacin. High within- and between-run accuracy for both gliclazide (% error of -8.00 to 0.45%) and ciprofloxacin (% error of -10.00 to 7.63%) were demonstrated. The intra- and inter-day precision (expressed as %CV) was <8 and 12% for gliclazide and ciprofloxacin, respectively. Both analytes were stable during storage and sample processing. The method reported in this study can be implemented for pharmacokinetic interaction study in rats., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Introduction: Solid lipid nanoparticles (SLNs) are considered a promising system in enhancing the oral bioavailability of poorly water-soluble drugs; owing to their intrinsic ability to increase the solubility together with protecting the incorporated drugs from extensive metabolism., Objective: Exploiting such properties, SLNs loaded with gliclazide (GLZ) were developed in an attempt to improve the oral bioavailability and the anti-diabetic action of GLZ, together with prolonging its duration of action for better glycemic control., Methods: SLNs were prepared by ultra-sonication technique using glyceryl behenate (Compritol ® 888 ATO) as a lipid matrix and poloxamer 188 (PLX) as a stabilizer. A 2*3 asymmetrical factorial design was adopted to study the effect of different stabilizer concentrations at different sonication times on the shape, and size of the particles, PDI and drug loading. The selected optimum formulation was then freeze dried using trehalose di-hydrate as a cryo-protectant in different ratios with respect to glyceryl behenate concentration. After freeze drying, the formulation was tested for in-vitro drug release, pharmacokinetics, and pharmacodynamics. Safety of the selected formula was established after carrying out a subacute toxicity study., Results: The factorial design experiment resulted in an optimum formulation coded 10F2 (150 mg PLX/10 min sonication). Scanning electron micrographs showed spherical particles with smooth surface, whereas a ratio of 2:1 cryo-protectant:lipid was found to be optimum with particle size of 245.9 ± 26.2 nm, polydispersity index of 0.482 ± 0.026, and biphasic in-vitro release with an initial burst effect, followed by a prolonged release phase. On the other hand, the selected SLNs exhibited prolonged drug release when compared with the GLZ commercial immediate release (IR) tablets (Diamicron ® ). Pharmacokinetics study showed about 5-fold increase in GLZ oral bioavailability loaded in SLNs when compared with raw GLZ powder. Pharmacodynamics study on a diabetic rat model confirmed the better anti-diabetic action of GLZ loaded SLNs when compared to raw GLZ powder. Subacute toxicity study indicated the safety of SLNs upon repetitive oral administration., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Nazief et al.)

Objective: The aim of this study was to optimize the formulation of alginate-gelatin (AL-GL) beads containing gliclazide (GLZ) employing design of experiments (DOE). Significance: DOE enabled identification of the interaction between the studied factors, deep understanding of GLZ release pattern and acceleration of the optimization process. Methods: A three-factor, three-level face centered design was employed. The effects of GLZ content (GLZ%, X 1 ), polymer ratio (AL:GL ratio, X 2 ), crosslinker concentration (glutaraldehyde, GA%, X 3 ), and their interaction on incorporation efficiency (IE) and release rate were studied. The optimized formulation was prepared using numerical optimization and evaluated by DSC, FT-IR, SEM and release rate studies. Results: Increasing GA% (X 3 ) decreased IE (Y 1 ) with the highest magnitude of effect among the studied factors. On the other hand, increasing alginate content in AL:GL ratio (X 2 ) increased IE (Y 1 ). The amount of GLZ released Q 0.5h , Q 2h (pH 1.2) and Q 4h (pH 7.4) decreased by increasing GLZ% (X 1 ) and AL:GL ratio (X 2 ). Both drug content and AL:GL ratio appeared to affect water penetration into the gel matrix and drug release. Generally, there was a direct relationship between GA% (X 3 ) and GLZ release in pH 1.2 (Q 0.5h and Q 2h ). However, in pH 7.4 (Q 4h ), increasing GA% decreased GLZ release. In addition, increasing GA% caused deviation from zero-order release model. The actual responses of the optimized formulation were in close agreement with the predicted ones. Conclusion: The selected factors and their levels studied in the optimization design were useful for tailoring the anticipated formulation characteristics and GLZ release pattern.

Drug delivery and therapeutic challenges of gliclazide, a BCS class II drug used in type 2 diabetes mellitus (T2DM) can be overcome by exploring smarter carriers of second-generation nanocrystals (SGNCs). A combined method of emulsion diffusion, high-pressure homogenization and solvent evaporation method were employed in the preparation of gliclazide loaded poly (D, L-lactide-co-glycolide) (PLGA) SGNCs. Taguchi experimental design was adopted in fabrication of Gliclazide SGNc using Gliclazide -PLGA ratio at 1:0.5, 1:0.75, 1:1 with stabilizer (Poloxamer-188, PEG 4000, HPMC E15 at 0.5, 0.75, 1% w/v). The formulated gliclazide of SGNCs were investigated for physicochemical properties, in vitro drug release, and in vivo performance studies using type-2 diabetes rat model. The formulation (SGNCF1) with Drug: PLGA 1: 0.5 ratio with 0.5% w/v Poloxamer-188 produced optimized gliclazide SGNCs. SGNCF1 showed spherical shape, small particle size (106.3 ± 2.69 nm), good zeta potential (-18.2 ± 1.30 mV), small PDI (0.222 ± 0.104) and high entrapment efficiency (86.27 ± 0.222%). The solubility, dissolution rate and bioavailability of gliclazide SGNCs were significantly improved compared to pure gliclazide. The findings emphasize gliclazide SGNCs produce faster release initially, followed by delayed release with improved bioavailability, facilitate efficient delivery of gliclazide in T2DM with better therapeutic effect.

This study aimed to investigate the bioequivalence of 2 formulations of gliclazide modified-release tablets 60 mg in 48 healthy Caucasian volunteers under fasting conditions. A test product, Gliclazide MR (Ranbaxy Laboratories Limited, now Sun Pharmaceutical Industries, India), was compared with a reference product, Diamicron MR (Servier, France). The study was performed under a single-dose, 2-treatment, 2-period, 2-sequence crossover design in a fasted condition with a washout period of 21 days. Blood samples were collected for 96 hours after drug administration. Drug plasma concentrations were determined by a liquid chromatography-tandem mass spectrometry method. Analysis of pharmacokinetic characteristics was based on a noncompartmental model. The logarithmically transformed data of C max and AUC were analyzed for 90% confidence intervals using analysis of variance. There was no significant difference in pharmacokinetic characteristics between the products, and the 90% confidence intervals were within the acceptance range of 80.00%-125.00%. The investigated products were bioequivalent under fasted conditions., (© 2018, The American College of Clinical Pharmacology.)

In this study, drug delivery system of gliclazide, a poorly soluble drug, was developed and evaluated in vitro and in vivo. We synthesized five series of mPEG-PCL di block copolymers. The structure of the copolymers was characterized by 1 H-NMR, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) techniques. In this study, gliclazide was encapsulated within micelles through a single-step nano-precipitation method, leading to formation of gliclazide/mPEG-PCL micelles. The resulting micelles were characterized further by various techniques such as DLS and AFM. The serum glucose lowering effect of gliclazide micelles was studied in streptozotocin-diabetic rats and were compared with the gliclazide treated rats. The results showed that the zeta potential of micelles was about -14.9 mV and the average size was 83.12 nm. Gliclazide was encapsulated into mPEG-PCL micelles with loading capacity of 21.05 ± 0.14% and entrapment efficiency of 94.11 ± 0.12%. In vivo testing of the gliclazide micelles in diabetic rats demonstrated a significant antidiabetic effect of gliclazide micelles after the 7 day that lasted for 21 days when compared with gliclazide powder. The results suggest that gliclazide micelles are a valuable system for the sustained delivery of gliclazide.

Type 2 diabetes mellitus is a worldwide health problem. Many drugs can be used in its treatment. One of them is gliclazide - the sulfonylurea derivative. It is dosed in modified release tablets. The study aimed to determine the minimum steady-state concentration of gliclazide at patients taking modified release tablets. Fasting plasma glucose, insulin level, and glycated hemoglobin were also assayed in this study. Ten patients of the primary care physician clinic took 30-90 mg of gliclazide daily. The statistical analysis proved that there is a statistically significant correlation between insulin level and body weight (p = 0.044) as well as between the dose and gliclazide concentrations (p = 0.015) and also between insulin level and minimum concentration of the drug (p = 0.0074). The linear correlation between dose and gliclazide's minimum steady state concentration proved its linear pharmacokinetics. The correlation between the minimum concentration of gliclazide and insulin level might be a potential predictor of patients compliance., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

The therapeutic use of glimepiride and gliclazide shows substantial inter-individual variation in pharmacokinetics and pharmacodynamics in human populations, which might be caused by genetic differences among individuals. The aim of this study was to assess the effect of CYP2C9 and OATP1B1 genetic polymorphisms on the metabolism and transport of glimepiride and gliclazide. The uptake of glimepiride and gliclazide was measured in OATP1B1*1a, *5 and *15-HEK293T cells, and their metabolism was measured using CYP2C9*1, *2 and *3 recombinase by LC-MS. Glimepiride in OATP1B1*1a, *5 and *15-HEK293T cells had V max values of 155 ± 18.7, 80 ± 9.6, and 84.5 ± 8.2 pmol/min/mg, while gliclazide had V max values of 15.7 ± 4.6, 7.2 ± 2.5, and 8.7 ± 2.4 pmol/min/mg, respectively. The clearance of glimepiride and gliclazide in OATP1B1*5 and *15 was significantly reduced compared to the wild-type. Glimepiride in the presence of CYP2C9*1, *2 and *3 recombinase had V max values of 21.58 ± 7.78, 15.69 ± 5.59, and 9.17 ± 3.03 nmol/min/mg protein, while gliclazide had V max values of 15.73 ± 3.11, 10.53 ± 4.06, and 6.21 ± 2.94 nmol/min/mg protein, respectively. The clearance of glimepiride and gliclazide in CYP2C9*2 and *3 was significantly reduced compared to the wild-type. These findings collectively indicate that OATP1B1*5 and *15 and CYP2C9*2 and *3 have a significant effect on the transport and metabolism of glimepiride and gliclazide.

Sulphonylurea drugs stimulate insulin secretion from pancreatic β-cells primarily by inhibiting ATP sensitive potassium (KATP) channels in the β-cell membrane. The effective sulphonylurea concentration at its site of action is significantly attenuated by binding to serum albumin, which makes it difficult to compare in vitro and in vivo data. We therefore measured the ability of gliclazide and glibenclamide to inhibit KATP channels and stimulate insulin secretion in the presence of serum albumin. We used this data, together with estimates of free drug concentrations from binding studies, to predict the extent of sulphonylurea inhibition of KATP channels at therapeutic concentrations in vivo. KATP currents from mouse pancreatic β-cells and Xenopus oocytes were measured using the patch-clamp technique. Gliclazide and glibenclamide binding to human plasma were determined in spiked plasma samples using an ultrafiltration-mass spectrometry approach. Bovine serum albumin (60g/l) produced a mild, non-significant reduction of gliclazide block of KATP currents in pancreatic β-cells and Xenopus oocytes. In contrast, glibenclamide inhibition of recombinant KATP channels was dramatically suppressed by albumin (predicted free drug concentration <0.1%). Insulin secretion was also reduced. Free concentrations of gliclazide and glibenclamide in the presence of human plasma measured in binding experiments were 15% and 0.05%, respectively. Our data suggest the free concentration of glibenclamide in plasma is too low to account for the drug's therapeutic effect. In contrast, the free gliclazide concentration in plasma is high enough to close KATP channels and stimulate insulin secretion., Competing Interests: The authors have declared that no competing interests exist.

Gliclazide is a second-generation sulphonylurea drug widely used in the treatment of type 2 diabetes. However, there is no single report to describe the population pharmacokinetics of gliclazide in animal models. This study was aimed to evaluate the population pharmacokinetics (PK) of gliclazide in normal and alloxan-induced diabetic rabbits using nonlinear mixed effects modeling. A total of 90 New Zealand white rabbits were administered with three doses (4.13, 8.27 and 16.53 mg/kg b.wt) of gliclazide by an oral route. Blood samples were collected up to 24 hr and the gliclazide concentrations in rabbit were determined using the HPLC method. The non-compartmental and classical compartmental PK analyses were performed using Phoenix WinNonlin. Population PK analysis of gliclazide was performed using nonlinear mixed-effects model software NONMEM and Phoenix NLME considering the weight, age, sex, health and dose as covariates. The final population values for clearance (CL), volume of distribution (V) and the absorption rate constant (k a ) were 5270 ml/hr, 55700 ml and 0.708 hr -1 , respectively. The inter-individual variability in gliclazide CL, V and k a was 16.3%, 14.9% and 26.5%, respectively. There was no significant difference between NONMEM and Phoenix NLME pharmacokinetic results. The visual predictive check and bootstrap analysis confirmed the predictive ability, model stability and precision of the parameter estimates from this model. This population PK model demonstrated that gliclazide pharmacokinetics is best described by one-compartment model with first-order absorption in rabbits. Body weight is a covariate that significantly influences gliclazide kinetic disposition in rabbits., (Copyright © 2018 John Wiley & Sons, Ltd.)

Background and Objective: Gliclazide is a drug commonly used in type 2 diabetes mellitus. Recently, gliclazide has shown desirable pharmacological effects such as immunoregulatory and anti-clotting effects, which suggests potential applications in type 1 diabetes mellitus (T1DM). Gliclazide has variable absorption after oral administration, and thus using targeted-delivery techniques, such as microencapsulation, may optimise gliclazide absorption and potential applications in T1DM. Bile acids such as cholic acid have shown microcapsule-stabilising and controlled-release effects, and thus their incorporation into gliclazide microcapsules may further optimise gliclazide release, absorption and antidiabetic effects. Accordingly, this study aimed to examine the hypoglycaemic effects of gliclazide microcapsules with and without cholic acid, in a rat model of T1DM., Methods: Thirty-five alloxan-induced T1DM rats were randomly divided into five equal groups and gavaged a single dose of empty microcapsules, gliclazide, gliclazide microcapsules, gliclazide-cholic acid or gliclazide-cholic acid microcapsules. Blood samples were collected over 10 h post-dose and analysed for blood glucose and gliclazide serum concentrations., Results: Gliclazide microcapsules exerted a hypoglycaemic effect in the diabetic rats, and cholic acid incorporation diminished the hypoglycaemic effects, which suggests the lack of synergistic effects between gliclazide and cholic acid. In addition, neither microencapsulation nor cholic acid incorporation optimised gliclazide absorption which suggests that hypoglycaemic effects of gliclazide are independent of its absorption and serum concentrations. This also suggests that hypoglycaemic effects of gliclazide may be associated with gut-metabolic activation rather than gut-targeted delivery and systemic absorption., Conclusion: Gliclazide microcapsules exerted hypoglycaemic effects in T1DM rats independent of insulin and thus may have potentials in treatment of T1DM.

Purpose: To prepare the supramolecular cocrystals of gliclazide (GL, a BCS class II drug molecule) via mechanochemical route, with the goal of improving physicochemical and biopharmaceutical properties., Methods: Two cocrystals of GL with GRAS status coformers, sebacic acid (GL-SB; 1:1) and α-hydroxyacetic acid (GL-HA; 1:1) were screened out using liquid assisted grinding. The prepared cocrystals were characterized using thermal and analytical techniques followed by evaluation of antidiabetic activity and pharmacokinetic parameters., Results: The generation of new, single and pure crystal forms was characterized by DSC and PXRD. The crystal structure determination from PXRD revealed the existence of both cocrystals in triclinic (P-1) crystal system. The hydrogen bonded network, determined by material studio was well supported by shifts in FTIR and SSNMR. Both the new solid forms displayed improved solubility, IDR, antidiabetic activity and pharmacokinetic parameters as compared to GL., Conclusions: The improvement in these physicochemical and biopharmaceutical properties corroborated the fact that the supramolecular cocrystallization may be useful in the development of pharmaceutical crystalline materials with interesting network and properties.

Background: In recent years, controlled and sustained release drug delivery system has become the focus of pharmaceutical researchers. Some technologies aimed to develop the controlled and sustained release of the drug, which used to be administered several times a day and generate plasma concentration fluctuation. As all, a controlled drug release rate has always been a goal pursued by researchers. This paper introduced a controlled delivery hydrophilic matrix system, and evaluated their relevance between in vitro and in vivo behaviors., Methods: The matrix tablets were fabricated by direct powder compression method. Single-factor test and the orthogonal experimental design were used to find out the optimal formulation. And the in vivo pharmacokinetics study was also evaluated in this paper., Results: The amount of WSR N301 and low viscosity materials significantly affect the drug release. Compared with commercially available sustained-release tablets Diamicron®, the pharmacokinetics parameters of these matrix tablets exhibited similar blood profiles, and other parameters such as prolonged Tmax, Cmax, MRT and similar bioavailability. However, this matrix system showed unstable blood profiles in comparison with two-layer-core osmotic pump tablet. The IVIVC study suggested that there was a good correlation between absorption in vivo and drug release in vitro., Conclusion: Zero-order controlled drug release of hydrophilic matrix system has the simpler manufacture process. And it will be a promising system to control drug release. Due to the disadvantage of hydrophilic matrix tablets in vivo release, for further research the zero-order delivery of PEO matrix tablets system, some pharmaceutical technology are needed to decrease the influence of gastrointestinal peristalsis. Therefore, the study of polyethylene oxide hydrophilic matrix tablets provides a promising formulation for promoting the development of a drug delivery system., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Gliclazide is a second-generation oral hypoglycemic drug used for the treatment of noninsulin-dependent diabetes mellitus. It belongs to the sulfonylurea class that stimulates insulin secretion from pancreatic β-cells by inhibiting ATP-dependent potassium channels. Gliclazide also possesses unique antioxidant properties and other beneficial hemobiological effects. This profile represents a comprehensive description of the physical properties, chemical synthesis, spectroscopic characterization (FTIR, 1 H NMR, 13 C NMR, UV, and single-crystal X-ray), methods of analysis, pharmacological actions, and pharmacokinetic and pharmacodynamic properties of the title drug., (© 2017 Elsevier Inc. All rights reserved.)

In this study, dextran (Dex) has been cross-linked with epichlorohydrin (Ech) to yield cross-linked hydrogels. These gels were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, Thermogravimetric analysis (TGA), and Scanning electron microscopy (SEM). The water absorption behavior of gels was studied in simulating gastric fluid (SGF) and simulating intestinal fluid (SIF) at 37°C. The data was interpreted by various kinetic models. The swelling was found to be totally diffusion controlled. The equilibrium data was also used to calculate network parameters. The antidiabetic drug Gliclazide (Glz) was loaded to the gels and its release was investigated in the media of varying pH, to mimic transition from mouth to colon. Finally, the in-vivo study on "Albino Wistar rats" was carried out to investigate the efficiency of the formulations. The drug-loaded hydrogel was found to be quite effective in reducing the glucose level at lower administration frequency as compared to the plain drug., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Gliclazide (G) is used to treat type 2 diabetes (T2D), and also has anti-platelet, anti-radical, and anti-inflammatory effects. G has poor water solubility and high inter-individual variations in absorption, limiting its application in type 1 diabetes (T1D). The bile acid, chenodeoxycholic acid (CDCA), has permeation-enhancing effects. Sodium alginate (SA) was used to microencapsulate G and CDCA to produce control (G-SA) and test (G-CDCA-SA) microcapsules. Both microcapsules showed uniform structure, morphology, and good stability profiles. CDCA reduced G-release at pH 7.8, while G-release was negligible at lower pH values in both microcapsules. CDCA incorporation resulted in less swelling and stronger microcapsules, suggesting improved stability.

In this study, a novel asymmetric membrane osmotic pump capsule of gliclazide (GLC) solid dispersion was developed to achieve a controlled drug release. The capsule shells were obtained by wet phase inversion process using cellulose acetate as semi-permeable membrane, glycerol and kolliphor P188 as pore formers, then filled with the mixture of GLC solid dispersion and pH modifiers. Differentiate from the conventional formulations, sodium carbonate was chosen as the osmotic agent and effervescent agent simultaneously to control the drug release, instead of the polymer materials. The ternary solid dispersion of GLC, with polyethylene glycol 6000 and kolliphor P188 as carriers, was prepared by solvent-evaporation method, realizing a 2.09-fold increment in solubility and dissolution rate in comparison with unprocessed GLC. Influence of the composition of the coating solution and pH modifiers on the drug release from the asymmetric membrane capsule (AMC) was investigated. The ultimate cumulative release of the optimal formulation reached 91.32% in an approximately zero-order manner. The osmotic pressure test and dye test were conducted to validate the drug release mechanism from the AMC. The in vivo pharmacokinetic study of the AMC indicated a 102.66±10.95% relative bioavailability compared with the commercial tablet, suggesting the bioequivalence between the two formulations. Consequently, the novel controlled delivery system with combination of solid dispersion and AMC system is capable of providing a satisfactory alternative to release the water-insoluble drugs in a controlled manner., (Copyright © 2016. Published by Elsevier B.V.)

Hyperinsulinism, one of the most important causes of hypoglycaemia, can be congenital or acquired. Rarely, drug toxicity can be a reason for hyperinsulinism. In the context of Munchausen syndrome by proxy (MSP), toxicity usually occurs in children due to drug administration by a parent or caregiver. A 7-year-old girl was referred to our department due to a hyperglycaemic period and hypoglycaemic episodes. On admission, gliclazide was initiated due to her hyperglycaemia, which we attributed to maturity onset diabetes of the young. However, during follow-up, hypoglycaemic levels were detected. Despite cessation of gliclazide, hypoglycaemic seizures occurred. Even with the medications administered, hypoglycaemia could not be prevented. During follow-up, the mother's affect, characterized by anxiety and interest in her daughter's medical care, appeared discordant with the situation. Due to our suspicion of MSP, we discovered toxic levels of gliclazide in the blood and urine samples which had been sent to the toxicology laboratory to search for hypoglycaemic agents. The patient was isolated, and all medications were stopped. After isolation, her hypoglycaemia disappeared, and she became hyperglycaemic (250 mg/dl). Physicians should consider the possibility of MSP in hyperinsulinaemic patients with discordant laboratory results and clinical symptoms, even if the child's parents display great concern., (© 2016 S. Karger AG, Basel.)

Enhancement of the dissolution rate of the poorly water-soluble hypoglycemic agent, gliclazide, by the aid of lyophilization was investigated. Mannitol, sodium lauryl sulfate (SLS) and polyvinyl pyrrolidone (PVP-k-30) were employed in different weight ratios (43%, 56% and 64% w/w, respectively) as water-soluble excipients in the formulation. Lyophilized systems were found to exhibit extremely higher in vitro dissolution rate compared to the unprocessed drug powder. Solid state characterization of the lyophilized systems using X-ray powder diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry techniques revealed that dissolution enhancement was attributable to transformation of gliclazide from the crystalline to an amorphous state in the solid dispersion formed during the lyophilization process. The gastrointestinal absorption and hypoglycemic effect of the lyophilized gliclazide/SLS system were investigated following oral administration to Albino rabbits. Cmax and area under the plasma concentration-time curve of gliclazide (AUC0-12) after administration of the lyophilized formulations were significantly higher than those obtained after administration of the unprocessed gliclazide.

In previous studies carried out in our laboratory, a bile acid formulation exerted a hypoglycaemic effect in a rat model of type 1 diabetes (T1D). When the antidiabetic drug gliclazide was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-deoxycholic acid (G-DCA), with good structural properties, excipient compatibility and which exhibited pseudoplastic-thixotropic characteristics. The aim of this study is to test the slow release and pH controlled properties of this new formulation. The aim is also to examine the effect of DCA on G release kinetics at various pH values and different temperatures. Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared including: G-SA (control) and G-DCA-SA (test) at a constant ratio (1:3:30), respectively. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, 3, 7.4 and 7.8 and temperatures of 25 °C and 37 °C. The new formulation is further optimised by the addition of DCA. DCA reduced bead-swelling of the microcapsules at pH 7.8 and 3 at 25 °C and 37 °C, and even though bead size remains similar after DCA addition, the percentage of G release was enhanced at high pH values (pH 7.4 and 7.8, p < 0.01). The new formulation exhibits colon-targeted delivery and the addition of DCA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and DCA to the lower intestine.

Drug Gliclazide (Glz) has limited solubility and low bioavailability. In order to obtain a controlled release of this drug and to improve its bioavailability, the drug has been loaded into poly(caprolactone) (PCL)/poly(acrylic acid) (PAAc) hydrogels, prepared by free radical polymerization of acrylic acid in the presence of poly(caprolactone) in acetone medium using azo-isobutyronitrile as initiator and N,N' methylene bisacrylamide as cross-linking agent. The swelling behaviour of these hydrogels has been investigated in the physiological gastric and intestinal fluids to obtain an optimum composition suitable for delivery of a biologically active compound. The gels were loaded with anti-diabetic drug Glz and a detailed investigation of release of drug has been carried out. Various kinetic models have been applied on the release data. Finally, the Albino wistar rats were treated for Streptozotocin plus nicotinamide - induced diabetes using a Glz-loaded PCL/PAAc hydrogel. The results indicated a fair reduction in the glucose level of rats.

The aim of this work is to reduce the cost of required sampling for the estimation of the area under the gliclazide plasma concentration versus time curve within 60 h (AUC0-60t ). The limited sampling strategy (LSS) models were established and validated by the multiple regression model within 4 or fewer gliclazide concentration values. Absolute prediction error (APE), root of mean square error (RMSE) and visual prediction check were used as criterion. The results of Jack-Knife validation showed that 10 (25.0 %) of the 40 LSS based on the regression analysis were not within an APE of 15 % using one concentration-time point. 90.2, 91.5 and 92.4 % of the 40 LSS models were capable of prediction using 2, 3 and 4 points, respectively. Limited sampling strategies were developed and validated for estimating AUC0-60t of gliclazide. This study indicates that the implementation of an 80 mg dosage regimen enabled accurate predictions of AUC0-60t by the LSS model. This study shows that 12, 6, 4, 2 h after administration are the key sampling times. The combination of (12, 2 h), (12, 8, 2 h) or (12, 8, 4, 2 h) can be chosen as sampling hours for predicting AUC0-60t in practical application according to requirement.

The objective of present work was to design and evaluate gliclazide push-pull osmotic pump (PPOP) coated with aqueous colloidal polymer dispersions-Eudragit(®) RL 30D and Eudragit(®) RS 30D. The influence of diacetin, diethyl phthalate (DEP), dibutyl sebacate (DBS) and triethyl citrate (TEC) on the free Eudragit(®) RL 30D and Eudragit(®) RS 30D films as plasticizers on drug release were studied. Among these four plasticizers, diacetin offered the smoothest surface of the cast films, and it displayed greatest water vapor transmission coefficient. Free RL and RS films with diacetin also exhibited greatest erosion compared with the other three plasticizers. On the other hand, TEC, DEP and DBS showed greater water absorption. When compared with CA-coated gliclazide PPOP, Eudragit-coated ones showed a f(2) factor of 71.7, indicating the similarity between the release profile of the two formulations. The prepared Eudragit-coated gliclazide PPOP showed typical Zero-order release characteristics, with R being 0.9953. In the in vivo evaluation, the mean relative oral bioavailability of Eudragit-coated PPOP compared to CA-coated ones was 106.9%, demonstrating good bioequivalence. Both of their in vitro-in vivo correlation (IVIVC) showed linear relationship, with R(2) being 0.9955 (Eudragit-coated PPOP) and 0.9987 (CA-coated PPOP), respectively. These results suggested that PPOP coated with Eudragit(®) RL 30D and RS 30D could overcome drawbacks of organic solution coating and promote the development of PPOP.

In recent studies we showed that gliclazide has no hypoglycemic effect on type 1 diabetic (T1D) rats while MKC does, and their combination exerted a better hypoglycemic effect than MKC alone. We also showed that the most hypoglycemic effect was noticed when T1D rats were treated with probiotics then gavaged with MKC + gliclazide (blood glucose decreased from 24 ± 3 to 10 ± 2 mmol/l). The aim of this study is to investigate the influence of probiotics on MKC pharmacokinetics when coadministered with gliclazide, in T1D rats. 80 male Wistar rats (weight 350 ± 50 g) were randomly allocated into 8 groups (10 rats/group), 4 of which were injected with alloxan (30 mg/kg) to induce T1D. Group 1 was healthy and group 2 was diabetic. Groups 3 (healthy) and 4 (diabetic) were gavaged with probiotics (75 mg/kg) every 12 h for 3 days and 12 h later all groups received a single oral dose of MKC + gliclazide (4 and 20 mg/kg respectively). The remaining 4 groups were treated in the same way but administered MKC + gliclazide via the i.v. route. Blood samples collected from T1D rats prior to MKC + gliclazide revealed that probiotic treatment alone reduced blood glucose levels twofold. When coadministered with gliclazide, the bioavailability of MKC was reduced in healthy rats treated with probiotics but remained the same in diabetic pretreated rats. The decrease in MKC bioavailability, when administered with gliclazide, caused by probiotic treatment in healthy but not diabetic rats suggests that probiotic treatment induced MKC metabolism or impaired its absorption, only in healthy animals. The different MKC bioavailability in healthy and diabetic rats could be explained by different induction of presystemic elimination of MKC in the gut by probiotic treatment.

Solid dispersion technique is widely used to improve the dissolution rate of drugs. Most investigators relied on the in-vitro characterization and considered the enhanced dissolution as an indication of improved bioavailability. The current study investigated the effects of binary and ternary solid dispersions of gliclazide with polyethylene glycol 6000 (PEG 6000) and/or pluronic F68 (PL F68) on the dissolution of gliclazide. The study also investigated the intestinal absorption in presence of solid dispersion components. The latter employed the in-situ rabbit intestinal perfusion technique. Preparation of binary solid dispersion with PEG 6000 or PL F68 significantly enhanced the dissolution rate compared to pure drug. The ternary solid dispersion of gliclazide with both polymers resulted in rapid drug dissolution with most drug being released in the first five minutes. The intestinal perfusion indicated the possibility of complete drug absorption from the small intestine. This, together with slow dissolution of pure drug suggested that the absorption of gliclazide is dissolution rate limited. The presence of PEG 6000 did not alter the intestinal absorption but PL F68 showed a trend of enhanced intestinal absorption of the drug. Ternary solid dispersion can thus provide rapid absorption due to rapid dissolution and potential increase in intestinal permeability.

Aims: To find out the pharmacokinetic (PK) and pharmacodynamic (PD) parameters for assessing the bioequivalence of three marketed products. To study the relationship between the pharmacokinetics of gliclazide and pharmacodynamic effect in healthy male volunteers., Methods: This was an open label, balanced, randomized, 3-treatment, 3-sequence, 3 period, single-dose, cross-over bioavailability study in which 18 healthy adults were randomized to receive gliclazide 80 mg with 7 days wash out between treatments. The drug was administered with 240 ml of 20% glucose solution after a 10 h overnight fasting. Pharmacokinetic parameters like t(max), C(max), AUC(0-t), AUC(0-∞), AUC(0-t) / AUC(0-∞) and t(1/2) and pharmacodynamic parameters like maximum effect (minimum glucose level in the body, C(minglu)), time to minimum glucose level in the body (T(cminglu)) and partial AUC were calculated for all the products., Results: The values for mean ± SD for age, height and weight of the volunteers were 28.00 ± 22.68, 165.78 ± 5.56 and 56.78 ± 13.37 respectively. There were total 4 withdrawn subjects and 1 drop out. Within batch accuracy of the method were in the range of 95.5 - 101.7%, 99.1 - 106.1% and 96.2 - 104.2% for three consecutive batches. The 90% CI for log transformed data of the PK and PD were within the acceptance range of 80.0 - 125.0%., Conclusions: This population PKPD analysis has characterized the relationship between the exposure to gliclazide and its hypoglycemic effect. The test products A & B compared to reference product R were bioequivalent on the basis of pharmacokinetic and pharmacodynamic parameters. Finally it is recommended that the more costly product R can be safely switched with less costly products i.e. A and B.

The aim of this study was to develop a drug-specific absorption model for gliclazide (GLK) using mechanistic gastrointestinal simulation technology (GIST) implemented in GastroPlus(TM) software package. A range of experimentally determined, in silico predicted or literature data were used as input parameters. Experimentally determined pH-solubility profile was used for all simulations. The human jejunum effective permeability (P (eff)) value was estimated on the basis of in vitro measured Caco-2 permeability (literature data). The required PK inputs were taken from the literature. The results of the simulations were compared with actual clinical data and revealed that the GIST-model gave accurate prediction of gliclazide oral absorption. The generated absorption model provided the target in vivo dissolution profile for in vitro-in vivo correlation and identification of biorelevant dissolution specification for GLK immediate-release (IR) tablets. A set of virtual in vitro data was used for correlation purposes. The obtained results suggest that dissolution specification of more than 85% GLK dissolved in 60 min may be considered as "biorelevant" dissolution acceptance criteria for GLK IR tablets., (© 2010 American Association of Pharmaceutical Scientists)

The low water-solubility of gliclazide (GL) leads to a low dissolution rate and variable bioavailability. The aim of this study was to investigate the effect of micronization on the absorption and pharmacokinetics of GL after oral administration in rats. GL microcrystals were prepared using solvent-change and pH-shift methods. Scanning electron microscopy showed considerable changes in the shape and size of crystals using both methods. In the optimized formulation of each method, the particle size of treated GL was reduced about 30 (from 290 to 9.9 microm) and 61 times (to 4.76 microm) by solvent-change and pH-shift methods, respectively. Recrystallized samples showed faster dissolution rate than untreated GL particles. Glucose-lowering effect, C(max), and area under the drug concentration-time profile (area under the curve (AUC)) were compared in diabetic and normal rats. AUC and C(max) were increased by microcrystals in both groups of animals. Administration of 40 mg/kg of GL in the form of untreated drug and microcrystals obtained by solvent-change and pH-shift methods caused 12.49% and 21.04% enhancement in glucose-lowering effect of GL in diabetic rats, respectively.

Background and Objective: CYP2C9 is the major contributor to gliclazide metabolic clearance in vitro, while the pharmacokinetics of gliclazide modified release are affected mainly by CYP2C19 genetic polymorphisms in vivo. This study aims to investigate the influence of CYP2C9 and CYP2C19 genetic polymorphisms on the pharmacokinetics and pharmacodynamics of gliclazide in healthy Chinese Han volunteers., Methods: Eighteen healthy Han subjects with various combinations of CYP2C9 and CYP2C19 genotypes received 80 mg gliclazide. Plasma gliclazide concentrations were measured by a liquid chromatography-tandem mass spectrometry method for 84 h and plasma glucose and insulin levels were measured up to 15 h post-dose., Results and Discussion: There was no difference in either pharmacokinetic and or pharmacodynamic parameters of gliclazide when group A (CYP2C9*1/*1, CYP2C19 extensive metabolizers) was compared with group B (CYP2C9*1/*3, CYP2C19 *1/*1). When group C (CYP2C9*1/*1 and CYP2C19 poor metabolizers) was compared with group A, the AUC(0-∞) and C(max) in group C were significantly higher [83.94 ± 40.41 vs. 16.39 ± 5.10 μg·h/mL (P = 0.000) and 1.50 ± 0.85 vs. 0.45 ± 0.18 μg/mL (P = 0.000)], and the oral clearance was significantly lower [1.17 ± 0.63 vs. 5.38 ± 1.86 L/h (P = 0.000)]. The half-life of gliclazide was also significantly prolonged in group C subjects when compared with that of group A (33.47 ± 12.39 vs. 19.34 ± 10.45 h), but the difference was not significant (P = 0.052). The increase in serum glucose level at 11 h after dosing (ΔC(glu11)) in group C was significantly higher than that of group A (-1.08 ± 0.42 vs. 0.22 ± 1.01 mmol/L, P = 0.022). The corresponding insulin levels showed no difference between the two groups., Conclusion: CYP2C9*3 was not associated with any change in the disposition of gliclazide. CYP2C19 polymorphisms appear to exert the dominant influence on the pharmacokinetics of gliclazide in healthy Chinese Han subjects, and may also affect the observed pharmacodynamics of the drug as a result.

To evaluate by simulation the statistical properties of normalized prediction distribution errors (NPDE), prediction discrepancies (pd), standardized prediction errors (SPE), numerical predictive check (NPC) and decorrelated NPC (NPC(dec)) for the external evaluation of a population pharmacokinetic analysis, and to illustrate the use of NPDE for the evaluation of covariate models. We assume that a model M(B) has been built using a building dataset B, and that a separate validation dataset, V is available. Our null hypothesis H(0) is that the data in V can be described by M(B). We use several methods to test this hypothesis: NPDE, pd, SPE, NPC and NPC(dec). First, we evaluated by simulation the type I error under H(0) of different tests applied to the four methods. We also propose and evaluate a single global test combining normality, mean and variance tests applied to NPDE, pd and SPE. We perform tests on NPC and NPC(dec), after a decorrelation. M(B) was a one compartment model with first order absorption (without covariate), previously developed from two phase II and one phase III studies of the antidiabetic drug, gliclazide. We simulated 500 external datasets according to the design of a phase III study. Second, we investigated the application of NPDE to covariate models. We propose two approaches: the first approach uses correlation tests or mean comparisons to test the relationship between NPDE and covariates; the second evaluates NPDE split by category for discrete covariates or quantiles for continuous covariates. We generated several validation datasets under H(0) and under alternative assumptions with a model without covariate, with one continuous covariate (weight), or one categorical covariate (sex). We calculated the powers of the different tests using simulations, where the covariates of the phase III study were used. The simulations under H(0) show a high type I error for the different tests applied to SPE and an increased type I error for pd. The different tests present a type I error close to 5% for the global test appied to NPDE. We find a type I error higher than 5% for the test applied to classical NPC but this test becomes close to 5% for NPC(dec). For covariate models, when model and validation dataset are consistent, type I error of the tests are close to 5% for both effects. When validation datasets and models are not consistent, the tests detect the correlation between NPDE and the covariate. We recommend to use NPDE over SPE for external model evaluation, since they do not depend on an approximation of the model and have good statistical properties. NPDE represent a better approach than NPC, since in order to perform tests on NPC, a decorrelation step must be applied before. NPDE, in this illustration, is also a good tool to evaluate model with or without covariates.

Objective: To evaluate the bioequivalence of a gliclazide/metformin combination tablet (at dose of 80/500 mg) with co-administration of metformin (500 mg) and gliclazide (80 mg) as individual tablets in healthy male Korean volunteers., Subjects, Materials and Methods: The study was conducted as an open-label, randomized, 2-period crossover design in 32 healthy male Korean volunteers who received a combination tablet of gliclazide/metformin at a dose of 80/500 mg or co-administration of gliclazide and metformin as individual tablets in each study period. There was a 7-day washout period between doses. Serum concentrations of gliclazide and metformin up to 32 hours after administration were determined using a validated HPLC method with UV detection. The pharmacokinetic parameters such as AUC0-t (the area under the curve from zero to the time), AUC0- yen (the area under the curve from zero to infinity), Cmax (maximum serum concentration), tmax (time to reach Cmax) and t1/2 (terminal half-life), were analyzed by non-compartmental analysis. Analysis of variance (ANOVA) was carried out using logarithmically transformed AUC0-t, AUC0- yen and Cmax, and untransformed tmax. In addition, blood glucose concentration was also logarithmically transformed and analyzed. Tolerability and safety profiles were also investigated., Results: There were no significant differences between the single combination tablet and the individual tablets in AUC0-t, AUC0- yen, Cmax and blood glucose concentration. The point estimates (90% confidence intervals) for AUC0-t, AUC0- yen and Cmax were 1.0293 (0.9476 - 1.1178), 1.0253 (0.9185 - 1.1443) and 1.0425 (0.9986 - 1.0883) for gliclazide, and 0.9887 (0.9137 - 1.0697), 0.9915 (0.9189 - 1.0697) and 0.9882 (0.9295 - 1.0505) for metformin, respectively, satisfying the bioequivalence criteria of 80 - 125% as proposed by the US FDA and the Korean legislation. Significant F test values were found between the subjects and subject nested sequence (SEQ) for AUC0-t and Cmax, indicating substantial inter-subject variation in the pharmacokinetics of gliclazide and metformin. However, a SEQ effect in the two-way crossover design did not impair the bioequivalence conclusion. No statistically significant differences were found for tmax and blood glucose concentration between two treatments., Conclusion: The combination tablet of gliclazide/metformin is bioequivalent to co-administration of individual tablets. As a result, the combination tablets are regarded therapeutically equivalent and exchangeable to the co-administration of individual tablets in clinical practice. Moreover, the combination tablets are expected to improve convenience and adherence to prescribed therapy and to contribute to better blood glucose control for patients with Type 2 diabetes.

The aim of this study is to investigate how the semisynthetic bile acid; 3alpha,7alpha-dihydroxy-12-keto-5beta-cholanate, also known as 12-monoketocholic acid (MKC) influences the ileal permeation of the antidiabetic drug gliclazide in healthy and diabetic rats. Male Wistar rats were divided into 10 groups (n = 32), of which 5 comprised healthy rats (1 to 5) and 5 diabetic rats (6 to 10). Group 1 was used to measure the permeation of gliclazide (200 microg/ml) alone (control) while in groups 2 to 5 gliclazide permeation was measured in the presence of MKC (50 microg/ml), glibenclamide (100 mug/ml), rifampicin (100 mug/ml) and verapamil (30 microg/ml), respectively, using Ussing chambers. Groups 6 to 10 were treated in the same way, after the induction of type 1 diabetes with alloxan (iv 30 mg/kg). In tissues from healthy rats, there was a 9-fold reduction in the mucosal to serosal permeation of gliclazide in the presence of MKC (p < 0.001) while glibenclamide and rifampicin reduced the permeation of gliclazide in both directions; mucosal to serosal and serosal to mucosal and verapamil had no effect. In contrast, in diabetic rats, there was no net transport of gliclazide alone or after the addition of MKC, glibenclamide, rifampicin or verapamil. The lack of any net flux of gliclazide in diabetic rats suggests the lack of action of drug transporters involved or the suppression of their expression. Furthermore, MKC-induced inhibition of mucosal to serosal unidirectional flux of gliclazide, in healthy rats, can be the result of the selective inhibition of Mrp3.

The aim of this study was to investigate the pharmacokinetics and glucose-lowering activity of gliclazide alone and in combination with the bile acid salt, sodium 3alpha,7alpha-dihydroxy-12-keto-5beta-cholanate (MKC), in a rat model of type I diabetes. Eighty male Wistar rats were divided into eight groups (n=10). Four groups were treated with alloxan (30 mg/kg) to induce diabetes. One group of healthy and one group of diabetic rats were administered gliclazide (20 mg/kg), MKC (4 mg/kg) or a combination of gliclazide (20 mg/kg) and MKC (4 mg/kg). One group of healthy and one group of diabetic rats were used as controls. Blood samples were collected from the tail vein 6 hours post-dose and the plasma was analyzed for glucose concentrations. It was found that gliclazide bioavailability was increased in healthy rats when coadministered with MKC, but there was no difference in glucose levels. Gliclazide bioavailability was much lower in diabetic rats and was not altered by MKC. However, the hypoglycemic effect of the combination of gliclazide and MKC was significantly greater in diabetic rats than that of gliclazide alone. It was demonstrated that the combination of MKC and gliclazide produced a significant hypoglycemic effect in a rat model of Type I diabetes. As gliclazide alone does not have a hypoglycemic effect on Type I diabetic rats, it can be concluded that gliclazide potentiates hypoglycemic effect of MKC in Type I diabetic rats.

The action of gliclazide, a sulphonylurea with beneficial extrapancreatic effects in diabetes, may be enhanced by administering probiotics. The aim of this study was to investigate the influence of probiotics on gliclazide pharmacokinetics and the effect of both probiotics and gliclazide on blood glucose levels in healthy and diabetic rats. Male Wistar rats (2 to 3 months, weight 350 +/- 50 g) were randomly allocated to 4 groups (n =10), two of which were treated with alloxan i.v. 30 mg/kg to induce diabetes. One group of healthy and one group of diabetic rats were then gavaged with probiotics (75 mg/kg) for three days after which a gliclazide suspension (20 mg/kg) was administered by gavage to all groups. Blood samples were collected from the tail vein at various time points for 10 hours post-administration for the determination of blood glucose and gliclazide serum concentrations. It was found that probiotic treatment had no effect on blood glucose levels in healthy rats, but it reduced them (up to 2-fold; p < 0.01) in diabetic rats. Probiotic treatment reduced gliclazide bioavailability in healthy rats (3-fold) whereas it increased gliclazide bioavailability in diabetic rats (2-fold; p < 0.01). Gliclazide had no effect on blood glucose levels in either healthy or diabetic rats despite the changes in its bioavailability. In conclusion, the probiotic treatment of diabetic rats increases gliclazide bioavailability and lowers blood glucose levels by insulin-independent mechanisms, suggesting that the administration of probiotics may be beneficial as adjunct therapy in the treatment of diabetes.

Background and Purpose: Patients commonly take complementary medicines in conjunction with conventional drugs without clear evidence of safety or the risk of herb-drug interactions. The aim of this study was to assess potential pharmacokinetic (PK) and pharmacodynamic (PD) interactions between St John's wort and gliclazide in healthy subjects with different cytochrome P450 2C9 (CYP2C9) genotypes., Experimental Approach: A crossover controlled study was conducted in 21 healthy subjects. Each received gliclazide (80 mg) either alone or during 15 days treatment with St John's wort. The area under the plasma concentration-time curve (AUC(0-infinity)), apparent clearance (CL/F) and elimination half-life (t 1/2) of gliclazide and incremental changes in glucose and insulin AUC(0-4) were compared. CYP2C9*2 and CYP2C9*3 alleles were identified using PCR followed by restriction enzyme digestion analysis., Key Results: St John's wort significantly altered gliclazide pharmacokinetics in all except for four healthy subjects. The mean ratio and 90% confidence interval (CI) of gliclazide AUC(0-infinity) and CL/F were 0.67 (0.55-0.81) and 1.50 (1.24-1.81), respectively, after St John's wort treatment. St John's wort decreased gliclazide t (1/2), with mean ratio and 90% CI of 0.85 (0.74-0.93). There were no significant changes in glucose or insulin AUC(0-4) after St John's wort treatment and no significant differences according to CYP2C9 genotype., Conclusions and Implications: Treatment with St John's wort significantly increases the apparent clearance of gliclazide which is independent of CYP2C9 genotype. People with diabetes receiving this combination should be closely monitored to evaluate possible signs of reduced efficacy.

The aim of this study was to investigate the influence of sodium 3alpha,7alpha-dihydroxy-12-keto-5beta-cholanate (MKC) on the ileal permeation of gliclazide in healthy and diabetic rats treated with probiotics. Male Wistar rats (2-3 months, 350 +/- 50 g) were randomly allocated into four groups (n = 32); Groups 1 and 2 were healthy controls and Groups 3 and 4 were diabetic rats (alloxan 30 mg/kg was administered i.v.), which were administered probiotics for three days after the rats became diabetics. The rats were sacrificed and tissues were mounted on Ussing chambers. Then, gliclazide (200 microg/ml) was added to all the groups, while MKC (50 microg/ml) was given to Groups 2 and 4, for the measurement of the mucosal to serosal absorption Jss(MtoS) and serosal to mucosal secretion Jss(StoM) of gliclazide. In the tissues of healthy rats treated with probiotics, MKC stimulated the net absorption of gliclazide by stimulating the absorptive and reducing the secretory unidirectional fluxes, while in tissues from diabetic rats treated with probiotics, MKC had no effect. In healthy rats treated with probiotics, the degradation of MKC by bacterial polypeptides produced divalent bile salts that inhibited Mrp2, which resulted in reducing secretion and stimulating the absorption of gliclazide. In contrast, in diabetic rats treated with probiotics, MKC had no effect possibly due to a difference in the metabolic profile and resulting in no net flux., (Copyright 2008 Prous Science, S.A.U. or its licensors. All rights reserved.)

A sensitive and selective liquid chromatographic--mass spectrometric (LC-MS) method for the determination of gliclazide (CAS 21187-98-4) in human plasma has been developed. Sample treatment was based on protein precipitation with acetonitrile. Analytical determination was carried out on a C18 column interfaced with a triple quadrupole mass spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase was acetonitrile-water containing 10 mmol/l ammonium acetate, pH 3.5 adjusted with acetic acid (75:25) at the flow rate of 1.0 ml/min. Both the analyte and the internal standard glipizide (CAS 29094-61-9) were detected by use of selected ion monitoring mode. The method was linear in the concentration range of 0.025-2.5 microg/mL. The lower limit of quantification (LLOQ) was 0.025 microg/mL. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range was less than 9.8%. The accuracy determined at three concentrations (0.05, 0.2 and 1.5 microg/mL for gliclazide) was within +/- 10.11% in terms of relative error (RE). The method herein described was successfully applied for the evaluation of pharmacokinetic profiles of gliclazide sustained release tablets in 18 healthy volunteers. The results show that AUC, Tmax, Cmax and T1/2 between the test formulation and reference formulation have no significant difference (P > 0.05). Relative bioavailability is 96.7.4 +/- 12.9%.

Objective: Gliclazide is a potent antidiabetic agent because of its capability to decrease blood glucose level via stimulating endogenous insulin secretion from beta-pancreas cells. Gliclazide is insoluble in water and has low dissolution rate. In this study, polyethylene glycol (PEG) 6000 was used as a matrix to disperse gliclazide in the solid state, and the pharmacokinetic profile of this solid dispersion was studied in rats., Design: The solid dispersion of Gliclazide:PEG 6000 (1:4) was prepared by solvent evaporation method., Main Outcome Measures: Samples characterization included differential scanning calorimetry (DSC), infrared spectroscopy (IR), X-ray diffraction (XRD), and solubility and dissolution test. In vivo study was carried out in healthy rats, randomly. After a single dose of oral administration, blood samples were collected pre-dose (15 min before) and 1, 2, 3, 4, 5, 6, 8, 10, and 12 h post-dose. Plasma concentration of gliclazide was determined by high pressure liquid chromatography method using C-18 column, with mobile phase KH2PO4 (pH 4.6)-acetonitril (40:60 v/v) and UV detection at 229 nm., Results: Results showed that there were no differences in DSC, IR spectroscopy, XRD, and dissolution test between the solid dispersion and physical mixture. In vivo data showed that the Tmax of gliclazide in solid dispersion and physical mixture was significantly decreased, while the Cmax, AUC(0-12), and AUC(0-infinity) were significantly increased compared to gliclazide alone. These results indicate that the rapid Tmax was due to rapid absorption of gliclazid across the GI tract membrane. Increased Cmax, AUC(0-12), and AUC(0-infinity) indicate a better absorption of gliclazide in solid dispersion and physical mixture than of gliclazide alone., Conclusion: Increased in gliclazide dissolution in the presence of PEG 6000 was followed by improved in vivo data.

This work investigates preparation of biodegradable beads with alginate polymer by ionotropic gelation method to take the advantages of the swelling and mucoadhesive properties of alginate beads for improving the oral delivery of the antidiabetic agent gliclazide. It demonstrates that the ionic gelation of alginate molecules offers a flexible and easily controllable process for manipulating the characteristics of the beads which are important in controlling the release rate and consequently the absorption of gliclazide from the gastrointestinal tract. Variations in polymer concentration, stirring speed, internal phase volume and the type of surfactant in the external phase were examined systemically for their effects on the particle size, incorporation efficiency and flow properties of the beads. The swelling behavior was strongly dependent on the polymer concentration in the formulations and the pH of the medium. The in vitro release experiments revealed that the swelling is the main parameter controlling the release rate of gliclazide from the beads. In vivo studies on diabetic rabbits showed that the hypoglycemic effect induced by the gliclazide loaded alginate beads was significantly greater and more prolonged than that induced by the marketed conventional gliclazide tablet (Gliclazide). The results clearly demonstrated the ability of the system to maintain tight blood glucose level and improved the patient compliance by enhancing, controlling and prolonging the systemic absorption of gliclazide.

The relationship between the pharmacokinetics of gliclazide and its antidiabetic efficacy were evaluated on the basis of experimental determination of changes with time in the plasma levels of this antidiabetic agent and those of glucose. The experiment included rats with both initial normal glycaemia and alloxan-induced hyperglycaemia (glycaemia increased by a minimum of 30%). Pharmacokinetic and pharmacodynamic parameters were examined in the interval of 30 to 180 min after p.o. administration of a single dose of 25 mg/kg of gliclazide. The drug was administered on day 4, following a single i.v. dose of either 50 mg/kg of alloxan (hyperglycaemic group) or the injection vehicle (control group). Even though the biological availability of gliclazide was similar in both normoglycaemic and hyperglycaemic animals, the gliclazide-induced hypoglycaemizing response was not uniform: until 60 min, the decrease of glycaemia was smaller in animals with alloxan hyperglycaemia (23% decrease at 60 min) in contrast to the normoglycaemic animals (36% decrease at 60 min), at later times, the intensity of this hypoglycaemizing effect of gliclazide persisted in the hyperglycaemic animals, while in the normoglycaemic ones, a reversal of the hypoglycaemizing effect occurred., (Copyright (c) 2007 John Wiley & Sons, Ltd.)

Aims: To investigate the influence of CYP2C9 and CYP2C19 genetic polymorphisms on the pharmacokinetics of gliclazide modified release (MR) in healthy Chinese subjects., Methods: In a single-dose pharmacokinetic study, 24 healthy male subjects with various CYP2C9 and CYP2C19 genotypes received an oral dose of 30 mg gliclazide MR and plasma was sampled for 72 h postdose. In a multiple-dose pharmacokinetic study, 17 other CYP2C9*1 homozygotes with various CYP2C19 genotypes received 30 mg gliclazide MR once daily for 6 days and plasma was sampled after the last dose. The plasma concentrations of gliclazide were measured using a validated LC/MS/MS method. CYP2C9 and CYP2C19 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism analysis., Results: In the single-dose study, no significant difference in any pharmacokinetic parameters was found in CYP2C9*1/*1, *1/*3 and *1/*13 subjects. In contrast, the AUC(0-infinity) of gliclazide was significantly increased by 3.4-fold [95% confidence interval (CI) 2.5, 4.7; P < 0.01] in CYP2C19 poor metabolizer (PM) subjects compared with CYP2C19*1 homozygotes. The half-life (t(1/2)) was prolonged from 15.1 to 44.5 h (P < 0.01). Similar differences were found in the multiple-dose study. The parameters of gliclazide AUC(ss), AUC(0-infinity) and C(max) were 3.4-fold (95% CI 2.9, 4.0), 4.5-fold (95% CI 3.8, 5.4) and 2.9-fold (95% CI 2.4, 3.4) increased (P < 0.01) in CYP2C19 PM subjects, respectively, compared with CYP2C19*1 homozygotes, and t(1/2) was increased from 13.5 to 24.6 h (P < 0.01)., Conclusions: The pharmacokinetics of gliclazide MR are affected mainly by CYP2C19 genetic polymorphism instead of CYP2C9 genetic polymorphism.

The aim of this study was to perform an in-vitro-in-vivo correlation (IVIVC) for two 60-mg gliclazide extended-release formulations (Fast and Slow release) given once a day and to compare their plasma concentrations over time. In-vitro release rate data were obtained for each formulation using the USP apparatus II, paddle stirrer at 50 and 100 rev min(-1) in 0.1 M HCl and pH 7.4 phosphate buffer. The similarity factor (f2) was used to analyse the dissolution data. Eighteen healthy subjects participated in the study, conducted according to a completely randomized, two-way crossover design. The formulations were compared using area under the plasma concentration-time curve, AUC(0-infinity), time to reach peak plasma concentration, Tmax, and peak plasma concentration Cmax, while correlation was determined between in-vitro release and in-vivo absorption. A linear correlation model was developed using percent absorbed data versus percent dissolved data from the two formulations. Predicted gliclazide concentrations were obtained by use of a curve fitting equation. Prediction errors were estimated for Cmax and area under the curve AUC(0-infinity) to determine the validity of the correlation. 0.1 M HCl at 50 rev min(-1) was found to be the most discriminating dissolution method. Linear regression analysis of the mean percentage of dose absorbed versus the mean percentage of in-vitro release resulted in a significant correlation (r2 > 0.98) for the two formulations. An average percent prediction error for Cmax was 4.15% for Fast release and 3.99% for Slow release formulation whereas for AUC(0-infinity) it was 6.36% and 4.66% for Fast release and Slow release formulation, respectively.

To be able to estimate accurately parameters entering a non-linear mixed effects model taking into account that one or more subpopulations of patients can exist rather than assuming that the entire population is best described by unimodal distributions for the random effects, we proposed a methodology based on the likelihood approximation using the Gauss-Hermite quadrature. The idea is to combine the estimation of the model parameters and the detection of homogeneous subgroups of patients in a given population using a Gaussian mixture for the distribution of the random effects. As the accuracy of the likelihood approximation is likely to govern the quality of the estimation of the different parameters entering the non-linear mixed effects model, we based this approximation on the use of an adjustable Gauss-Hermite quadrature. Moreover, to complete this methodology, we propose a strategy allowing the detection and explanation of heterogeneity based on the Kullback-Leibler test, which was used to estimate the number of components in the Gaussian mixture. In order to evaluate the capability of the method to take into account heterogeneity, this strategy was performed in a PK/PD analysis using the database and the structural model selected in a previous analysis. In this analysis, non-responders were found out using NONMEM [Beal and Sheiner. NONMEM Users Guides. NONMEM Project Group, University of California, San Francisio, 1992] in a population of diabetic patients treated with a once-a-day new formulation of an antidiabetic drug. The authors looked for a subpopulation of patients for whom the therapeutic effect would vanish. In this paper, we looked for subpopulations of patients exhibiting specificities with respect to different parameters entering the description of the effect. The results obtained with our approach are compared in terms of parameter estimation and heterogeneity detection to those obtained in the previous analysis.

Objective: The aim of this study was to evaluate, in human volunteers, the performance of one gliclazide tablet formulation (gliclazide 80 mg tablet from EMS Indústria Farmacêutica Ltda.) against two reference gliclazide tablet formulations (Diamicron 80 mg tablet from Servier do Brazil Ltda. and Diamicron 80 mg tablet from Servier (Ireland) Industries Limited)., Methods: The study had an open, randomized, three-period crossover design with a one-week washout interval between doses. The samples were obtained over a 48-h interval after each oral administration of gliclazide. The samples were extracted from plasma using diethylether : hexane (80 : 20, v/v) and the extracts were analyzed by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-MS/ MS). Chromatography was performed isocratically using a Jones Chromatography Genesis C8 120A 4u. The method had a chromatographic run-time of 2.5 min and a calibration curve of the range of 0.02- 10 microg x ml(-1) (r(2) > 0.9993). The limit of quantification was 0.02 microg x ml(-1)., Results: The geometric mean and 90% confidence intervals (CI) for the Gliclazide/Diamicron (Ireland) ratio were 588.68% (90% CI= 491.16, 705.58%) for AUClast, 423.50% (90% CI = 338.25, 530.23%) for AUCinf, and 1395.77% (90% CI= 1116.62, 1744.72%) for Cmax. The geometric mean and 90% confidence intervals (CI) for the Gliclazide/Diamicron (Brazil) ratio were 249.16% (90% CI = 207.96, 298.54%) for AUCiast, 249.16% (90% CI = 207.96 - 298.54%) for AUCinf, and 188.04% (90% CI - 151.72, 233.05%) for Cmax., Conclusion: Since the 90% CI for Cmax, AUClast and AUC(0-infinity) ratios were all outside the 125% interval proposed by the US Food and Drug Administration, we concluded that the gliclazide test formulation were not bioequivalent to either reference formulation. Interestingly, the pharmacokinetic parameters such as Cmax, AUClast of both reference formulations are compatible with neither the literature nor the profile of an immediate release formulation. In addition, both reference formulations were not bioequivalent in themselves, indicating significant differences in reference product formulation.

The aim of this study was to formulate and optimize gliclazide-loaded Eudragit nanoparticles (Eudragit L100 and Eudragit RS) as a sustained release carrier with enhanced efficacy. Eudragit L 100 nanoparticles (ELNP) were prepared by controlled precipitation method whereas Eudragit RSPO nanoparticles (ERSNP) were prepared by solvent evaporation method. The influence of various formulation factors (stirring speed, drug:polymer ratio, homogenization, and addition of surfactants) on particle size, drug loading, and encapsulation efficiency were investigated. The developed Eudragit nanoparticles (L100 and RS) showed high drug loading and encapsulation efficiencies with nanosize. Mean particle size altered by changing the drug:polymer ratio and stirring speed. Addition of surfactants showed a promise to increase drug loading, encapsulation efficiency, and decreased particle size of ELNP as well as ERSNP. Dissolution study revealed sustained release of gliclazide from Eudragit L100 as well as Eudragit RSPO NP. SEM study revealed spherical morphology of the developed Eudragit (L100 and RS) NP. FT-IR and DSC studies showed no interaction of gliclazide with polymers. Stability studies revealed that the gliclazide-loaded nanoparticles were stable at the end of 6 months. Developed Eudragit NPs revealed a decreased t(min) (ELNP), and enhanced bioavailability and sustained activity (ELNP and ERSNP) and hence superior activity as compared to plain gliclazide in streptozotocin induced diabetic rat model and glucose-loaded diabetic rat model. The developed Eudragit (L100 and RSPO) NP could reduce dose frequency, decrease side effects, and improve patient compliance.