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The fundamental idea underlying the use of amorphous solid dispersions (ASDs) is to make the most of the solubility advantage of the amorphous form of a drug. However, the drug stability becomes compromised due to the higher free energy and disorder of molecular packing in the amorphous phase, leading to crystallization. Polymers are used as a matrix to form a stable homogeneous amorphous system to overcome the stability concern. The present work aims to design ASD-based formulations under the umbrella of quality by design principles for improving oral drug bioavailability, using celecoxib (CXB) as a model drug. ASDs were prepared from selected polymers and tested both individually and in combinations, using various manufacturing techniques: high-shear homogenization, high-pressure homogenization, microfluidics-on-a-chip, and spray drying. The resulting dispersions were further optimized, resorting to a 32 full-factorial design, considering the drug:polymers ratio and the total solid content as variables. The formulated products were evaluated regarding analytical centrifugation and the influence of the different polymers on the intrinsic dissolution rate of the CXB-ASDs. Microfluidics-on-a-chip led to the amorphous status of the formulation. The in vitro evaluation demonstrated a remarkable 26-fold enhancement in the intrinsic dissolution rate, and the translation of this formulation into tablets as the final dosage form is consistent with the observed performance enhancement. These findings are supported by ex vivo assays, which exhibited a two-fold increase in permeability compared to pure CXB. This study tackles the bioavailability hurdles encountered with diverse active compounds, offering insights into the development of more effective drug delivery platforms. [ABSTRACT FROM AUTHOR]

Background/Objectives: This study aims to broaden the knowledge on co-amorphous phospholipid systems (CAPSs) by exploring the formation of CAPSs with a broader range of poorly water-soluble drugs, celecoxib (CCX), furosemide (FUR), nilotinib (NIL), and ritonavir (RIT), combined with amphiphilic phospholipids (PLs), including soybean phosphatidylcholine (SPC), hydrogenated phosphatidylcholine (HPC), and mono-acyl phosphatidylcholine (MAPC). Methods: The CAPSs were initially prepared at equimolar drug-to-phospholipid (PL) ratios by mechano-chemical activation-based, melt-based, and solvent-based preparation methods, i.e., ball milling (BM), quench cooling (QC), and solvent evaporation (SE), respectively. The solid state of the product was characterized by X-ray powder diffraction (XRPD), polarized light microscopy (PLM), and differential scanning calorimetry (DSC). The long-term physical stability of the CAPSs was investigated at room temperature under dry conditions (0% RH) and at 75% RH. The dissolution behavior of the CCX CAPS and RIT CAPS was studied. Results: Our findings indicate that SE consistently prepared CAPSs for CCX-PLs, FUR-PLs, and RIT-PLs, whereas the QC method could only form CAPSs for RIT-PLs, CCX-SPC, and CCX-MAPC. In contrast, the BM method failed to produce CAPSs, but all drugs alone could be fully amorphized. While the stability of each drug varied depending on the PLs used, the SE CAPS consistently demonstrated the highest stability by a significant margin. Initially, a 1:1 molar ratio was used for screening all systems, though the optimal molar ratio for drug stability remained uncertain. To address this, various molar ratios were investigated to determine the ratio yielding the highest amorphous drug stability. Our results indicate that all systems remained physically stable at a 1.5:1 ratio and with excess of PL. Furthermore, the CAPS formed by the SE significantly improves the dissolution behavior of CCX and RIT, whereas the PLs provide a slight precipitation inhibition for supersaturated CCX and RIT. Conclusions: These findings support the use of a 1:1 molar ratio in screening processes and suggest that CAPSs can be effectively prepared with relatively high drug loads compared to traditional drug–polymer systems. Furthermore, the study highlights the critical role of drug selection, the preparation method, and the PL type in developing stable and effective CAPSs. [ABSTRACT FROM AUTHOR]

Nanocomposites represent one of the most useful strategies for resolving the pharmaceutical challenge about the dissolution and delivery of poorly water-soluble drugs. Besides the compatibility between the drug and polymeric carriers, the physical shapes of materials also play their important roles on the release behaviors of a guest poorly water-soluble drug from the host polymeric matrices. In this study, three kinds of nanocomposites in the forms of homogeneous nanofibers (E1), spindles-on-a-string (E2), and beads-on-a-string (E3) were prepared using electrospinning with ketoprofen (KET) as the model drug and a mixture of ethylcellulose (EC) and polyvinylpyrrolidone (PVP) as the polymeric matrices. Controllable preparation mechanisms of these morphologies are disclosed based on the results of SEM, TEM, and processes observations. XRD and FTIR data demonstrated that KET was compatible with PVP and EC. In vitro dissolution tests verified that all the three nanocomposites were able to provide the typical bi-stage fast-sustained release profiles of KET. Whereas, the beads-on-a-string E3 had a better functional performance than the spindles-on-a-string E2, and the homogeneous nanofibers E1 in terms of the KET sustained release profiles in the second stage. The protocols reported here pioneered a new way for developing novel functional nanocomposites based on the process-shape-performance relationship. [ABSTRACT FROM AUTHOR]

Nanocomposites represent one of the most useful strategies for resolving the pharmaceutical challenge about the dissolution and delivery of poorly water-soluble drugs. Besides the compatibility between the drug and polymeric carriers, the physical shapes of materials also play their important roles on the release behaviors of a guest poorly water-soluble drug from the host polymeric matrices. In this study, three kinds of nanocomposites in the forms of homogeneous nanofibers (E1), spindles-on-a-string (E2), and beads-on-a-string (E3) were prepared using electrospinning with ketoprofen (KET) as the model drug and a mixture of ethylcellulose (EC) and polyvinylpyrrolidone (PVP) as the polymeric matrices. Controllable preparation mechanisms of these morphologies are disclosed based on the results of SEM, TEM, and processes observations. XRD and FTIR data demonstrated that KET was compatible with PVP and EC. In vitro dissolution tests verified that all the three nanocomposites were able to provide the typical bi-stage fast-sustained release profiles of KET. Whereas, the beads-on-a-string E3 had a better functional performance than the spindles-on-a-string E2, and the homogeneous nanofibers E1 in terms of the KET sustained release profiles in the second stage. The protocols reported here pioneered a new way for developing novel functional nanocomposites based on the process-shape-performance relationship.

About 40% of approved drugs and nearly 90% of drug candidates are poorly water-soluble drugs. Low solubility reduces the drugability. Effectively improving the solubility and bioavailability of poorly water-soluble drugs is a critical issue that needs to be urgently addressed in drug development and application. This review briefly introduces the conventional solubilization techniques such as solubilizers, hydrotropes, cosolvents, prodrugs, salt modification, micronization, cyclodextrin inclusion, solid dispersions, and details the crystallization strategies, ionic liquids, and polymer-based, lipid-based, and inorganic-based carriers in improving solubility and bioavailability. Some of the most commonly used approved carrier materials for solubilization techniques are presented. Several approved poorly water-soluble drugs using solubilization techniques are summarized. Furthermore, this review summarizes the solubilization mechanism of each solubilization technique, reviews the latest research advances and challenges, and evaluates the potential for clinical translation. This review could guide the selection of a solubilization approach, dosage form, and administration route for poorly water-soluble drugs. Moreover, we discuss several promising solubilization techniques attracting increasing attention worldwide. This review intends to summarize the solubilization techniques used for poorly water-soluble drugs, with a view to providing guidance to researchers to select solubilization techniques. [Display omitted] [ABSTRACT FROM AUTHOR]

Core–shell nanostructures are powerful platforms for the development of novel nanoscale drug delivery systems with sustained drug release profiles. Coaxial electrospinning is facile and convenient for creating medicated core–shell nanostructures with elaborate designs with which the sustained-release behaviors of drug molecules can be intentionally adjusted. With resveratrol (RES) as a model for a poorly water-soluble drug and cellulose acetate (CA) and PVP as polymeric carriers, a brand-new electrospun core–shell nanostructure was fabricated in this study. The guest RES and the host CA molecules were designed to have a reverse gradient distribution within the core–shell nanostructures. Scanning electron microscope and transmission electron microscope evaluations verified that these nanofibers had linear morphologies, without beads or spindles, and an obvious core–shell double-chamber structure. The X-ray diffraction patterns and Fourier transform infrared spectroscopic results indicated that the involved components were highly compatible and presented in an amorphous molecular distribution state. In vitro dissolution tests verified that the new core–shell structures were able to prevent the initial burst release, extend the continuous-release time period, and reduce the negative tailing-off release effect, thus ensuring a better sustained-release profile than the traditional blended drug-loaded nanofibers. The mechanism underlying the influence of the new core–shell structure with an RES/CA reverse gradient distribution on the behaviors of RES release is proposed. Based on this proof-of-concept demonstration, a series of advanced functional nanomaterials can be similarly developed based on the gradient distributions of functional molecules within electrospun multi-chamber nanostructures. [ABSTRACT FROM AUTHOR]

The use of animal experiments can be minimized with computational models capable of reflecting the simulated environments. One such environment is intestinal fluid and the colloids formed in it. In this study we used molecular dynamics simulations to investigate solubilization patterns for three model drugs (carvedilol, felodipine and probucol) in dog intestinal fluid, a lipid-based formulation, and a mixture of both. We observed morphological transformations that lipids undergo due to the digestion process in the intestinal environment. Further, we evaluated the effect of bile salt concentration and observed the importance of interindividual variability. We applied two methods of estimating solubility enhancement based on the simulated data, of which one was in good qualitative agreement with the experimentally observed solubility enhancement. In addition to the computational simulations, we also measured solubility in i) aspirated dog intestinal fluid samples and ii) simulated canine intestinal fluid in the fasted state, and found there was no statistical difference between the two. Hence, a simplified dissolution medium suitable for in vitro studies provided physiologically relevant data for the systems explored. The computational protocol used in this study, coupled with in vitro studies using simulated intestinal fluids, can serve as a useful prescreening tool in the process of drug delivery strategies development. Dog intestinal fluid was collected to: 1) assess the solubility of three poorly water-soluble drugs and 2) to construct a computational model of the fluid. The computational simulation results were then compared to the experimental data, and used to study the molecular interactions. [Display omitted] • In silico solubilization modeling of 3 drugs agrees with solubility measurements. • Dog intestinal fluid and lipid-based formulation synergistically solubilize drugs. • Simplified dissolution media enables physiologically relevant data generation. • In silico-in vitro approach can facilitate better understanding of LBF performance. [ABSTRACT FROM AUTHOR]

Increasing influx of poorly water-soluble drugs poses a significant challenge to oral drug delivery. Conventional solubilization techniques such as solid dispersion and cyclodextrin inclusion, while capable of improving drug dissolution, suffer from a great predicament in subsequent formulation processing. A novel “powder solution technology,” the liquisolid technique, has come to the forefront in dealing with drug solubilization and formulation of oral “problem” drugs. The liquisolid technique involves the adsorption of liquid medications onto suitable carrier and coating materials, followed by conversion into free-flowing, dry-looking, and compressible powders. In the liquisolid system, the drug is dispersed in an almost molecular state, which greatly contributes to drug dissolution and absorption. This review aims to present the fundamentals of liquisolid technology and update the concept of liquisolid processing to expand its applications. The trend of modern drug discovery, drug solubilization approaches, application of liquisolid technology in formulation innovation, formulation composition, and design of liquisolid systems were discussed in detail. Special emphasis was placed on the application of liquisolid technology to improve the dissolution and bioavailability of poorly water-soluble drugs. Accumulating evidence shows that the liquisolid technology has immense potential to improve oral delivery and facilitate the secondary development of insoluble drugs.

In this study, three kinds of electrohydrodynamic atomization (EHDA) processes (electrospraying, electrospinning, and coaxial electrospinning) are implemented to create hydroxypropyl methylcellulose (HPMC) based ultra‐thin products for providing the fast dissolution of a poorly water‐soluble drug ketoprofen (KET). An EHDA apparatus, characterized by a novel spinneret, is homemade for conducting the three processes. The three types of products are electrospun nanofibers E1, electrosprayed microparticles E2, and core‐shell nanofibers E3. SEM and TEM results indicate that they have the anticipated morphologies and inner structures. X‐ray diffraction and Fourier Transform Infrared results verify that KET is mainly amorphous in all the composites due to its fine compatibility with HPMC. In vitro dissolution tests demonstrate that the drug rapid release performances has an order of E3>E1>E2≫KET powders. The fast dissolution mechanisms are suggested and the advantages of the three products are compared. The super performance of E3 in furnishing the rapid release is attributed to a synergistic action of small size (of the shell thickness), high porosity, amorphous state of drug, and the solubility of HPMC. EHDA nanostructures can support the development of nano drug delivery systems (DDSs) through tailoring the spatial distribution of drug molecules within the nano products. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the drug loading capacity of phosphatidylcholine-based formulations for four poorly water-soluble drug substances (clofazimine, fenofibrate, artemether, cannabidiol). Two self-dispersing lipid formulations were investigated, which consisted of soybean phospholipids, medium-chain triglycerides and ethanol with a different phospholipid–oil ratio. The direct loading of the bulk formulation was conducted with dual centrifugation, which proved to be a suitable method for screening experiments with the highly viscous formulations. To estimate possible precipitation after dispersion in the gastrointestinal fluids, the solubility of the drugs was investigated in the dispersed formulations. For this purpose, nanodispersions were prepared from the bulk formulations via high pressure homogenization and subsequently subjected to passive loading. A newly developed HPLC method with Charged Aerosol Detection allowed a simultaneous evaluation of the content of soybean lecithin and medium-chain triglycerides in the nanodispersions. When comparing the two phosphatidylcholine-based formulations, a high content of oil was advantageous with regard to a high loading capacity. Drug substances with melting points below 150 °C exhibited a high solubility in the phospholipid-based formulations. A surprisingly high solubility was observed for artemether and cannabidiol with up to 13.0% and 33.3% drug loaded to the formulations, respectively. In the dispersions, a similar solubility as in the bulk formulations was obtained for fenofibrate and cannabidiol. Clofazimine yielded a higher loading result in the nanodispersions than in the bulk formulation. [ABSTRACT FROM AUTHOR]

In this study, bile acid-based vesicles and nanoparticles (i.e., bilosomes and biloparticles) are studied to improve the water solubility of lipophilic drugs. Ursodeoxycholic acid, sodium cholate, sodium taurocholate and budesonide were used as bile acids and model drugs, respectively. Bilosomes and biloparticles were prepared following standard protocols with minor changes, after a preformulation study. The obtained systems showed good encapsulation efficiency and dimensional stability. Particularly, for biloparticles, the increase in encapsulation efficiency followed the order ursodeoxycholic acid < sodium cholate < sodium taurocholate. The in vitro release of budesonide from both bilosytems was performed by means of dialysis using either a nylon membrane or a portion of Wistar rat small intestine and two receiving solutions (i.e., simulated gastric and intestinal fluids). Both in gastric and intestinal fluid, budesonide was released from bilosystems more slowly than the reference solution, while biloparticles showed a significant improvement in the passage of budesonide into aqueous solution. Immunofluorescence experiments indicated that ursodeoxycholic acid bilosomes containing budesonide are effective in reducing the inflammatory response induced by glucose oxidase stimuli and counteract ox-inflammatory damage within intestinal cells. [ABSTRACT FROM AUTHOR]

Cellulose beads emerge as carriers for poorly water-soluble drugs due to their eco-friendly raw materials and favorable porous structure. However, drug dissolution may be limited by their poor swelling ability and the presence of closed pores caused by shrinkage of the pristine cellulose beads. In this study, novel cellulose beads that can swell in acidic environment were prepared by introducing ethylenediamine (EDA) on dialdehyde cellulose (DAC), thereby addressing the shrinkage and closed pore problem of cellulose beads. The effect of the ratio of EDA on the swelling behavior and amine content of beads was studied. Three model drugs with different physicochemical properties were selected to study the physical state of loaded drugs and their release behavior. According to the results of XRPD and DSC, indomethacin and itraconazole loaded in the beads were amorphous at a drug loading of 20%, but fenofibrate was partially crystalline. Both bead size and the ratio of amine groups influenced the release behavior of the model drugs. The in vitro dissolution results showed that the cationic beads greatly improved the solubility and dissolution rate of the drug compared with the crystalline drug. Beads with a small size and high ratio of EDA tend to achieve a better drug dissolution rate and cumulative release percentage. Physical stability studies of the itraconazole-loaded beads were also implemented under four different temperature/humidity conditions for up to two months. The results showed that crystallization only appeared after two months of storage at 40°/75% RH, and the drug maintained a non-crystalline state in the other three storage conditions (0 °C/0 %RH, 0 °C/32 %RH, 25 °C/32 %RH). In conclusion, the novel pH-responsive cationic cellulose beads show great potential as a carrier for improving the rate and extent of dissolution of poorly soluble drugs and maintaining supersaturation.

The toxicity of local anesthetics is a serious problem, given their widespread use. One of the main causes of the side effects of local anesthetics is their non-selectivity of action in the body. A possible way to increase the selectivity of the action of drugs is to use the photopharmacology approach. Previously, we described the light-controlled local anesthetic ethercaine, the biological effect of which can be controlled using light, thereby increasing its selectivity of action. An important limitation of ethercaine was its low solubility in water, limiting the potential of this compound. In this work, we developed a dosage form of ethercaine, which allowed us to increase its solubility from 0.6% to 2% or more. The resulting 1% solution of ethercaine hydrochloride in 4% Kolliphor ELP had high biological activity on the surface anesthesia model, while demonstrating low acute toxicity in mice with intravenous administration (4–5 times less than that of lidocaine). [ABSTRACT FROM AUTHOR]

The prevalence of active pharmaceutical ingredients (APIs) with low water solubility has experienced a significant increase in recent years. These APIs present challenges in formulation, particularly for oral dosage forms, despite their considerable therapeutic potential. Therefore, the improvement of solubility has become a major concern for pharmaceutical enterprises to increase the bioavailability of APIs. A promising formulation approach that can effectively improve the dissolution profile and the bioavailability of poorly water-soluble drugs is the utilization of amorphous systems. Numerous formulation methods have been developed to enhance poorly water-soluble drugs through amorphization systems, including co-amorphous formulations, amorphous solid dispersions (ASDs), and the use of mesoporous silica as a carrier. Furthermore, the successful enhancement of certain drugs with poor aqueous solubility through amorphization has led to their incorporation into various commercially available preparations, such as ASDs, where the crystalline structure of APIs is transformed into an amorphous state within a hydrophilic matrix. A novel approach, known as ternary solid dispersions (TSDs), has emerged to address the solubility and bioavailability challenges associated with amorphous drugs. Meanwhile, the introduction of a third component in the ASD and co-amorphous systems has demonstrated the potential to improve performance in terms of solubility, physical stability, and processability. This comprehensive review discusses the preparation and characterization of poorly water-soluble drugs in ternary solid dispersions and their mechanisms of drug release and physical stability. [ABSTRACT FROM AUTHOR]

Drug solubility limits intravenous dosing for poorly water-soluble medicines, which misrepresents their bioavailability estimation. The current study explored a method using a stable isotope tracer to assess the bioavailability of drugs that are poorly water-soluble. HGR4113 and its deuterated analog, HGR4113-d7, were tested as model drugs. To determine the level of HGR4113 and HGR4113-d7 in rat plasma, a bioanalytical method using LC-MS/MS was developed. The HGR4113-d7 was intravenously administered to rats that were orally pre-administered HGR4113 at different doses; subsequently, the plasma samples were collected. HGR4113 and HGR4113-d7 were simultaneously determined in the plasma samples, and bioavailability was calculated using plasma drug concentration values. The bioavailability of HGR4113 was 53.3% ± 19.5%, 56.9% ± 14.0%, and 67.8% ± 16.7% after oral dosages of 40, 80, and 160 mg/kg, respectively. By eliminating the differences in clearance between intravenous and oral dosages at different levels, acquired data showed that the current method reduced measurement errors in bioavailability when compared to the conventional approach. The present study suggests a prominent method for evaluating the bioavailability of drugs with poor aqueous solubility in preclinical studies. [ABSTRACT FROM AUTHOR]

Drug amorphization is one of the major approaches in pharmaceutical sciences to improve the solubility and dissolution rate of poorly water-soluble drugs. Amorphous solid dispersions are widely discussed approach to convert the drug into an amorphous state but due to its high energy state, the system tends to recrystallize upon storage. Co-amorphous system is a single-phase low energy system that falls under the glass solution, a type of solid dispersion. Being low-energy state and single-phase, co-amorphous dispersions are more stable than amorphous solid dispersions. In co-amorphous dispersions, the homogeneous single phase is formed only with low molecular weight co-formers, so the amount of co-former required is relatively low and this reduces the bulk of the system. This aspect of co-amorphous dispersions makes it popular over the amorphous solid dispersions in the area of solid dispersion researchers. This review provides an overview of co-amorphous dispersions and their recent advances. Particularly, this review will discuss various factors (physical and chemical) that affect and provide the stability of the co-amorphous dispersions formulation. [ABSTRACT FROM AUTHOR]

A high percentage of marketed drugs suffer from poor water solubility and require an appropriate technique to increase their solubility. This study aims to compare physically modified and unmodified gum polymers extracted from Ziziphus spina-christi fruits as solid dispersion carriers for some drugs. Taguchi Orthogonal Design (L9) was chosen for the screening and optimization of the solid dispersions. The design has four factors: type of drug, type of polymer, type of solid dispersion process, and drug to polymer ratio. Each factor was varied in three stages and the total number of runs was 9 in triplicate. The polymer was physically modified by heating (M1ZG) or freeze-drying (M2ZG). The drugs were selected according to the biopharmaceutical classification system, namely loratadine and glimepiride (class II) and furosemide (class IV). Drugs were dispersed in the polymer in three different ratios 1: 1, 1: 2, and 1: 3. Solid dispersions were made by co-grinding, solvent evaporation, and kneading methods. Modified and unmodified polymers were characterized in terms of their organoleptic properties, solubility, powder flowability, density, viscosity, swelling index, and water retention capacity. Solid dispersions were characterized in terms of percentage practical yield, solubility improvement, and drug compatibility. The results showed that the organoleptic properties of polymers were not changed by the gum modification. The swelling index of the polymer was doubled in M1ZG. The viscosity and water retention capacity of the polymer was increased in both modified polymers. All solid dispersions showed a high practical percentage yield of more than 93%, the higher values ​​being more associated with loratadine and furosemide than with glimepiride. The improvement in solubility was observed in all solid dispersions prepared, the values ​​varying with the pH of the medium and the method of modification. The FTIR results indicated that there was no chemical interaction between these drugs and the polymer used. Analysis of the results according to the Taguchi orthogonal design indicated 51 folds aqueous solubility enhancement for loratadine using M2ZG polymer at a ratio of 1: 3 of Drug: polymer. This study showed the possibility of improving the solubility of other poorly soluble drugs.

Abstract Chagas disease is a neglected parasitic disease caused by Trypanosoma cruzi, whose treatment has remained unsatisfactory for over 50 years, given that it is limited to two drugs. Benznidazole (BZN) is an efficient antichagasic drug used as the first choice, although its poor water-solubility, irregular oral absorption, low efficacy in the chronic phase, and various associated adverse effects are limiting factors for treatment. Incorporating drugs with such characteristics into nanostructured lipid carriers (NLC) is a promising alternative to overcome these limiting obstacles, enhancing drug efficacy and bioavailability while reducing toxicity. Therefore, this study proposed NLC-BZN formulations in different compositions prepared by hot-melt homogenization followed by ultrasound, and the optimized formulation was characterized by FTIR, DRX, DSC, and thermogravimetry. Biological activities included in vitro membrane toxicity (red blood cells), fibroblast cell cytotoxicity, and trypanocidal activity against epimastigotes of the Colombian strain of T. cruzi. The optimized NLC-BZN had a small size (110 nm), negative zeta potential (-18.0 mV), and high encapsulation (1.64% of drug loading), as shown by infrared spectroscopy, X-ray diffraction, and thermal analysis. The NLC-BZN also promoted lower in vitro membrane toxicity (

The biopharmaceutical classification system groups low-solubility drugs into two groups: II and IV, with high and low permeability, respectively. Most of the new drugs developed for common pathologies present solubility issues. This is the case of lurasidone hydrochloride—a drug used for the treatment of schizophrenia and bipolar depression. Likewise, the stability problems of some drugs limit the possibility of preparing them in liquid pharmaceutical forms where hydrolysis and oxidation reactions can be favored. Lurasidone hydrochloride presents the isoindole-1,3-dione ring, which is highly susceptible to alkaline hydrolysis, and the benzisothiazole ring, which is susceptible to a lesser extent to oxidation. Herein, we propose to study the increase in the solubility and stability of lurasidone hydrochloride by the formation of higher-order inclusion complexes with hydroxypropyl-β-cyclodextrin. Several stoichiometric relationships were studied at between 0.5 and 3 hydroxypropyl-β-cyclodextrin molecules per drug molecule. The obtained products were characterized, and their solubility and stability were assessed. According to the obtained results, the formation of inclusion complexes dramatically increased the solubility of the drug, and this increased with the increase in the inclusion ratio. This was associated with the loss of crystalline state of the drug, which was in an amorphous state according to infrared spectroscopy, calorimetry, and X-ray analysis. This was also correlated with the stabilization of lurasidone by the cyclodextrin inhibiting its recrystallization. Phase solubility,1H-NMR, and docking computational characterization suggested that the main stoichiometric ratio was 1:1; however, we cannot rule out a 1:2 ratio, where a second cyclodextrin molecule could bind through the isoindole-1,3-dione ring, improving its stability as well. Finally, we can conclude that the formation of higher-order inclusion complexes of lurasidone with hydroxypropyl-β-cyclodextrin is a successful strategy to increase the solubility and stability of the drug. [ABSTRACT FROM AUTHOR]

In non-strongly interacting co-amorphous systems, addition of a polymer, to further stabilize the co-amorphous systems, may influence the phase behavior between the components. In this study, the evolution of the composition of the amorphous phase in the ternary system carvedilol (CAR)-tryptophan (TRP)-hydroxypropylmethyl cellulose (HPMC) was investigated, based upon previously formed and characterized binary systems to which the third component was added (CAR − TRP + HPMC, CAR − HPMC + TRP and TRP − HPMC + CAR). Ball milling was used as the preparation method for all binary and ternary systems. The influence of the milling time on the co-amorphous systems was monitored by DSC and XRPD. Addition of HPMC reduced the miscibility of CAR with TRP due to hydrogen bond formation between CAR and polymer. These bonds became dominant for the interaction pattern. In addition, when CAR or TRP exceeded the miscibility limit in HPMC, phase separation and eventually crystallization of CAR and TRP was observed. All ternary co-amorphous systems eventually reached the same composition, albeit following different paths depending on the initially used binary system. [ABSTRACT FROM AUTHOR]

The poor bioavailability of many newly developed active pharmaceutical ingredients (APIs) poses a major challenge in formulation development. To overcome this issue, strategies such as the preparation of amorphous solid dispersions (ASDs), and the application of the APIs in lipid nanocarriers or the wet-milling of the substances into nanoparticles have been introduced. In addition to an efficient formulation strategy, a dosage form that is accepted by all patients is also of great importance. To enable a simple application of the oral dosage form for all patients, orodispersible films (ODFs) are a very promising delivery platform for the APIs because the films directly disintegrate in the mouth. In this study, two poorly water-soluble APIs, fenofibrate and naproxen, were formulated using five different formulation strategies and then embedded in ODFs. It was found that the deliverable amount of API with one ODF highly depends on the formulation strategy as well as the physicochemical properties of the formulated API. The most promising film formulations were ASD-ODFs as well as films with API-loaded lipid nanoemulsions. Both showed a reduction of the dissolution time of the APIs from the ODF compared to an ODF with unformulated API micro particles. In addition, short disintegration times were achieved, although the mechanical film properties were slightly worse compared to the API-free film formulation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The poorly water-soluble drug was successfully entrapped into SLNs for oral delivery. • In vitro release data was able to predict the rank order of the oral bioavailability. • The SLN formulations enhanced the bioavailability by 2.5 and 1.8 fold. • Lipid concentration and particle size had an impact on the bioavailability. • In vitro-in vivo correlation was achieved using numerical deconvolution. The present study investigated the oral bioavailability of celecoxib when incorporated into solid lipid nanoparticles either dissolved or suspended. In vitro drug release in different media, in vivo performance, and in vitro-in vivo correlation were conducted. The results revealed that the compound was successfully encapsulated into the nanocarriers with good physicochemical properties for oral administration. The in vitro release profiles followed the Weibull model, with significant differences between the formulations containing the solubilized and the suspended compound. Furthermore, in vitro release data could be used to rank the observed in vivo bioavailability. The relative bioavailability of celecoxib from the solid lipid nanoparticles was 2.5- and 1.8-fold higher for the drug solubilized and suspended solid lipid nanoparticle formulation, respectively, when compared to the celecoxib reference. A significant difference was observed between the plasma concentration–time profiles and pharmacokinetic parameters for the three investigated formulations. Finally, this investigation displayed promising outcomes that both solubilized and suspended celecoxib in the lipid core of the solid lipid nanoparticles offers the potential to improve the compound's oral bioavailability and thereby reduce the dosing frequency. [ABSTRACT FROM AUTHOR]

Solid dispersion particles were prepared using an indomethacin (IND) as a model insoluble drug, poly- (vinylpyrrolidone-co-vinyl acetate) (VA64) as a water-soluble polymer and mannitol (Man) as an excipient. In case of hot-melt extrusion (HME) preparation, dissolution profile of every composition without Man was the same as others. The dissolution profile of composition including Man was much improved than others without Man. By contrast, the effect of Man addition was not recognized in case of spray drying (SD) preparation. Surface energy of the solid dispersion particles was measured by using an inverse gas chromatography surface analyzer (iGC-SEA). The surface energy of solid dispersion particles including Man prepared by the HME is much smaller than that without Man. However, in the SD preparation, there was no clear difference in the surface energy of solid dispersion particles with and without Man. The characteristic of the solid dispersion particles by the different manufacturing methods implied the difference of the dissolution improvement, in spite of the same composition. [ABSTRACT FROM AUTHOR]

Formulation-induced microbiota changes were linked with pro-inflammatory response. [Display omitted] • Amorphous solid dispersion and lipid nanoemulsion improve lurasidone bioavailability. • Lipid nanoemulsion triggered reductions in gut microbiota diversity and abundance. • The PVP-based amorphous solid dispersion was 'gut neutral'. Increasing attention is being afforded to understanding the bidirectional relationship that exists between oral drugs and the gut microbiota. Often overlooked, however, is the impact that pharmaceutical excipients exert on the gut microbiota. Subsequently, in this study, we contrasted the pharmacokinetic performance and gut microbiota interactions between two commonly employed formulations for poorly soluble compounds, namely 1) an amorphous solid dispersion (ASD) stabilised by poly(vinyl pyrrolidone) K-30, and 2) a lipid nanoemulsion (LNE) comprised of medium chain glycerides and lecithin. The poorly soluble antipsychotic, lurasidone, was formulated with ASD and LNE due to its rate-limiting dissolution, poor oral bioavailability, and significant food effect. Both the ASD and LNE were shown to facilitate lurasidone supersaturation within in vitro dissolution studies simulating the gastrointestinal environment. This translated into profound improvements in oral pharmacokinetics in rats, with the ASD and LNE exerting comparable ∼ 2.5-fold improvements in lurasidone bioavailability, compared to the pure drug. The oral formulations imparted contrasting effects on the gut microbiota, with the LNE depleting the richness and abundance of the microbial ecosystem, as evidenced through reductions in alpha diversity (Chao1 index) and operational taxonomical units (OTUs). In contrast, the ASD exerted a 'gut neutral' effect, whereby a mild enrichment of alpha diversity and OTUs was observed. Importantly, this suggests that ASDs are effective solubility-enhancing formulations that can be used without comprising the integrity of the gut microbiota – an integral consideration in the treatment of mental health disorders, such as schizophrenia, due to the role of the gut microbiota in regulating mood and cognition. [ABSTRACT FROM AUTHOR]

[Display omitted] The nanoparticle albumin bound™ (nab™) technology generally offers great potential for the formulation of poorly water-soluble drugs as albumin-stabilized nanosuspensions for intravenous use while avoiding solubilizers and cross-linking agents. The nab™ technology is a three-step process consisting of emulsification, high-pressure homogenization and solvent evaporation. Within this work, a screening approach was developed to predict whether active pharmaceutical ingredients are suitable for nab™ formulations. A design of experiments approach was used to investigate the effects of ultrasonic homogenization on an albumin-stabilized itraconazole nanosuspension. Based on this, a screening platform was developed, and subsequently evaluated and applied to a selection of poorly water-soluble drugs. The screening process to produce albumin-stabilized nanosuspensions consists of two process steps: Ultrasonic treatment, which combined emulsification and homogenization, followed by solvent evaporation. The results of the screening process were fully transferable to the standard three-step process of nab™ technology. In addition, based on drug screening, drug properties were highlighted that are important for the development of nab™ formulations. All in all, the nab™ technology is a promising but not universal formulation platform for poorly water-soluble drugs. Nevertheless, for some poorly soluble drugs it offers a valuable approach for the formulation of nanosuspensions for intravenous use. [ABSTRACT FROM AUTHOR]

Poor aqueous solubility is a common characteristic of new drug candidates, which leads to low or inconsistent oral bioavailability. This has sparked an interest in material efficient testing of solubility and dissolution rate. The aim was to develop a microgram scale video-microscopic method to screen the dissolution rates of poorly water-soluble drugs. This method was applied to six drugs (carvedilol, diazepam, dipyridamole, felodipine, fenofibrate, and indomethacin) in fasted state simulated intestinal fluid (FaSSIF), of indomethacin in buffer with varying pH, and of diazepam and dipyridamole in customized media. An additional aim was to track phase transformations for carbamazepine in FaSSIF. The dissolution rates and particle behavior of the drugs were investigated by tracking particle surface area over time using optical video-microscopy. Applying miniaturized UV spectroscopic dissolution resulted in a similar grouping of dissolution rates and pH effects, as for the video-microscopic setup. Using customized media showed that lysophospholipid enhanced the dissolution rate of diazepam and dipyridamole. The video-microscopic setup allowed for the nucleation of transparent particles on dissolving carbamazepine particles to be tracked over time. The developed setup offers a material efficient screening approach to group drugs according to dissolution rate, where the use of optical microscopy helps to achieve a high sample throughput. [ABSTRACT FROM AUTHOR]

Mirtazapine is a tetracyclic anti-depressant with poor water solubility. The aim of this study was to improve the dissolution rate of mirtazapine by delivering the drug as a liquisolid compact. Central composite design (CCD) was employed for the preparation of mirtazapine liquisolid compacts. In this, the impacts of two independent factors, i.e., excipient ratio (carrier:coating) and different drug concentration on the response of liquisolid system were optimized. Liquisolid compacts were prepared using propylene glycol as a solvent, microcrystalline cellulose as a carrier, and silicon dioxide (Aerosil) as the coating material. The crystallinity of the formulated drug and the interactions between the excipients were examined using X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR), respectively. The dissolution study for the liquisolid compact was carried out as per FDA guidelines. The results showed loss of crystallinity of the mirtazapine in the formulation and was completely solubilized in non-volatile solvent and equally dispersed throughout the powder system. Moreover, drug dissolution was found to be higher in liquisolid compacts than the direct compressed conventional tablets (of mirtazapine). The liquisolid technique appears to be a promising approach for improving the dissolution of poorly soluble drugs like mirtazapine. [ABSTRACT FROM AUTHOR]

Dissolution is a pivotal tool for oral formulations. Dissolution could be used to either reduce the risk of product failure through quality control or predict and understand in vivo performance of drug formulations. The latter is always challenging because multiple factors such as selection of media, gastrointestinal components, physiological factors, consideration of fasted and fed state are involved. Previously published dissolution methods such as one-step dissolution in individual simulated gastric fluid, simulated intestinal fluid, or phosphate buffer saline did not signify the realistic gastrointestinal transit effect. Docetaxel (DTX), a poorly water-soluble drug, is commercially available only as injectable dosage forms, and thus many publications studied the development of oral DTX formulations. In our previous report, we developed oral lipid-based DTX granules that showed higher oral absorption in rats compared to DTX powder. However, one-step dissolution in simulated gastric fluid showed no difference between DTX granules and DTX powder. Therefore, the present study aimed to develop new two-step biorelevant dissolution methods for DTX oral formulations. In the study, new two-step biorelevant dissolution methods in fasted or fed states with pancreatin were developed and compared with other previously reported dissolution methods. The new two-step biorelevant dissolution methods successfully discriminated the difference of dissolution between DTX granules and DTX powder, which reflected the in vivo difference of absorption of these two formulations. Moreover, food effects were confirmed for DTX. The new dissolution methods have the potential to be used to predict and understand in vivo performance of oral solid dosage forms. [ABSTRACT FROM AUTHOR]

Solid dispersion is a common useful technique which makes a crystal drug into amorphous. It improves the dissolution of the insoluble drug by using a rise in solubility, to increase the gastrointestinal tract absorption. In this study, dissolution characteristics of solid dispersion were improved by adding mannitol to the solid dispersion. The effect of mannitol addition to the solid dispersion formulation including PVP-K30 on the dissolution property was investigated. A large difference was observed between two manufacturing methods, a solvent distillation by an evaporator and a spray drying. The different effect of the mannitol addition appeared in the influence of the particle size of solid dispersion particles, although the composition of solid dispersion manufactured by both methods was the same. [ABSTRACT FROM AUTHOR]

A high percentage of marketed drugs suffer from poor water solubility and require an appropriate technique to increase their solubility. This study aims to compare physically modified and unmodified gum polymers extracted from Ziziphus spina-christi fruits as solid dispersion carriers for some drugs. Taguchi Orthogonal Design (L9) was chosen for the screening and optimization of the solid dispersions. The design has four factors: type of drug, type of polymer, type of solid dispersion process, and drug to polymer ratio. Each factor was varied in three stages and the total number of runs was 9 in triplicate. The polymer was physically modified by heating (M1ZG) or freeze-drying (M2ZG). The drugs were selected according to the biopharmaceutical classification system, namely loratadine and glimepiride (class II) and furosemide (class IV). Drugs were dispersed in the polymer in three different ratios 1: 1, 1: 2, and 1: 3. Solid dispersions were made by co-grinding, solvent evaporation, and kneading methods. Modified and unmodified polymers were characterized in terms of their organoleptic properties, solubility, powder flowability, density, viscosity, swelling index, and water retention capacity. Solid dispersions were characterized in terms of percentage practical yield, solubility improvement, and drug compatibility. The results showed that the organoleptic properties of polymers were not changed by the gum modification. The swelling index of the polymer was doubled in M1ZG. The viscosity and water retention capacity of the polymer was increased in both modified polymers. All solid dispersions showed a high practical percentage yield of more than 93%, the higher values ​​being more associated with loratadine and furosemide than with glimepiride. The improvement in solubility was observed in all solid dispersions prepared, the values ​​varying with the pH of the medium and the method of modification. The FTIR results indicated that there was no chemical interaction between these drugs and the polymer used. Analysis of the results according to the Taguchi orthogonal design indicated 51 folds aqueous solubility enhancement for loratadine using M2ZG polymer at a ratio of 1: 3 of Drug: polymer. This study showed the possibility of improving the solubility of other poorly soluble drugs. [ABSTRACT FROM AUTHOR]

[Display omitted] Developing co-amorphous systems is an attractive strategy to improve the dissolution rate of poorly water-soluble drugs. Various co-formers have been investigated. However, previous studies revealed that it is a challenge to develop satisfied acidic co-formers, e.g., acidic amino acids showed much poorer co-former properties than neutral and basic amino acids. Only a few acidic co-formers have been reported, such as aspartic acid, glutamic acid, and some other organic acids. Thus, this study aims to explore the possibility of adenosine monophosphate and adenosine diphosphate used as acidic co-formers. Mebendazole, celecoxib and tadalafil were used as the model drugs. The drug-co-former co-amorphous systems were prepared via ball milling and confirmed using XRPD. The dissolution study suggested that the solubility and dissolution rate of the drug-co-formers systems were increased significantly compared to the corresponding crystalline and amorphous drugs. The stability study revealed that using the two nucleotides as co-formers enhanced the physical stability of pure amorphous drugs. Molecular interactions were observed in MEB-co-former and TAD-co-former systems and positively affected the pharmaceutical performance of the investigated co-amorphous systems. In conclusion, the two nucleotides could be promising potential acidic co-formers for co-amorphous systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new structural amorphous solid dispersion of icariin. • A new side-by-side electrospinning process for combining polymeric excipients. • A co-shell solvent was utilized to ensure integrated Janus fibers for drug delivery. • Improved dissolution and permeation rates. • Clear preparation and action mechanisms. During the past several decades, nanostructures have played their increasing influences on the developments of novel nano drug delivery systems, among which, double-chamber Janus nanostructure is a popular one. In this study, a new tri-channel spinneret was developed, in which two parallel metal capillaries were nested into another metal capillary in a core–shell manner. A tri-fluid electrospinning was conducted with a solvent mixture as the shell working fluid for ensuring the formation of an integrated Janus nanostructure. The scanning electronic microscopic results demonstrated that the resultant nanofibers had a linear morphology and two distinct compartments within them, as indicated by the image of a cross-section. Fourier Transformation Infra-Red spectra and X-Ray Diffraction patterns verified that the loaded poorly water-soluble drug, i.e. icariin, presented in the Janus medicated nanofibers in an amorphous state, which should be attributed to the favorable secondary interactions between icariin and the two soluble polymeric matrices, i.e. hydroxypropyl methyl cellulose (HPMC) and polyvinylpyrrolidone (PVP). The in vitro dissolution tests revealed that icariin, when encapsulated within the Janus nanofibers, exhibited complete release within a duration of 5 min, which was over 11 times faster compared to the raw drug particles. Furthermore, the ex vivo permeation tests demonstrated that the permeation rate of icariin was 16.2 times higher than that of the drug powders. This improvement was attributed to both the rapid dissolution of the drug and the pre-release of the trans -membrane enhancer sodium lauryl sulfate from the PVP side of the nanofibers. Mechanisms for microformation, drug release, and permeation were proposed. Based on the methodologies outlined in this study, numerous novel Janus nanostructure-based nano drug delivery systems can be developed for poorly water-soluble drugs in the future. [ABSTRACT FROM AUTHOR]

In medicine, bioavailability is the percentage of a drug that enters the bloodstream and can be used to treat a patient. It has proven challenging throughout time to develop techniques that allow oral administration of most drugs, regardless of their properties, to achieve therapeutic systemic availability. This will be an impressive feat, considering that over 90% of pharmaceuticals are known to have limitations on their oral bioavailability. Improving bioavailability is crucial for optimizing the efficacy and safety of drugs. This review covers a wide range of techniques, including physical, chemical, and formulation approaches, highlighting their mechanisms, advantages, and limitations. Inhibitions of efflux pumps, inhibition of presystemic metabolism, and innovative drug delivery systems that capitalize on the gastrointestinal regionality of medicines are some of the new techniques that have drawn increased interest. Nanotechnology in pharmaceuticals is also being used in this field. We have collected the literature data from 2009 to 2024 using Science Direct, PubMed/Medline, Scopus, and Google Scholar., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Cancer is one of the leading causes of death worldwide. In the available treatments, chemotherapy is one of the most used, but has several associated problems, namely the high toxicity to normal cells and the resistance acquired by cancer cells to the therapeutic agents. The scientific community has been battling against this disease, developing new strategies and new potential chemotherapeutic agents. However, new drugs often exhibit poor solubility in water, which led researchers to develop functionalized nanosystems to carry and, specifically deliver, the drugs to cancer cells, targeting overexpressed receptors, proteins, and organelles. Thus, this review is focused on the recent developments of functionalized nanosystems used to carry poorly water-soluble drugs, with special emphasis on liposomes and albumin-based nanosystems, two major classes of organic nanocarriers with formulations already approved by the U.S. Food and Drug Administration (FDA) for cancer therapeutics.

• Physical stability of BLG-stabilized ASD was evaluated for five drugs. • Ketoconazole and rifaximin remained stable at 90 % loading for 12 months. • Stabilization mechanisms: steric confinement, hydrogen bonds, and others. • Crystal-patterned cluster search was introduced in molecular dynamics simulations. • In silico approach proved promising for prediction of long-term stability of ASDs. Our previous work shows that β-lactoglobulin-stabilized amorphous solid dispersion (ASD) loaded with 70 % indomethacin remains stable for more than 12 months. The stability is probably due to hydrogen bond networks spread throughout the ASD, facilitated by the indomethacin which has both hydrogen donors and acceptors. To investigate the stabilization mechanisms further, here we tested five other drug molecules, including two without any hydrogen bond donors. A combination of experimental techniques (differential scanning calorimetry, X-ray power diffraction) and molecular dynamics simulations was used to find the maximum drug loadings for ASDs with furosemide, griseofulvin, ibuprofen, ketoconazole and rifaximin. This approach revealed the underlying stabilization factors and the capacity of computer simulations to predict ASD stability. We searched the ASD models for crystalline patterns, and analyzed diffusivity of the drug molecules and hydrogen bond formation. ASDs loaded with rifaximin and ketoconazole remained stable for at least 12 months, even at 90 % drug loading, whereas stable drug loadings for furosemide, griseofulvin and ibuprofen were at a maximum of 70, 50 and 40 %, respectively. Steric confinement and hydrogen bonding to the proteins were the most important stabilization mechanisms at low drug loadings (≤ 40 %). Inter-drug hydrogen bond networks (including those with induced donors), ionic interactions, and a high T g of the drug molecule were additional factors stabilizing the ASDs at drug loading greater than 40 %. [Display omitted] [ABSTRACT FROM AUTHOR]

Co-amorphous systems have been proven to be a promising strategy to address the poor water solubility of poorly water-soluble drugs. Generally, the initial dissolution behaviors after co-amorphous system preparation and the potential recrystallization during storage are used to evaluate the performance of co-amorphous systems. However, this study reveals that decreased dissolution and unexpected increased dissolution were observed during storage though the co-amorphous systems maintained amorphous form. Three drugs (valsartan, tadalafil, mebendazole) and three co-formers (arginine, tryptophan, biotin) were used to prepare co-amorphous systems and the samples were stored for different times. After stored for 80 d, most of the co-amorphous systems maintained amorphous form, however, decreased and increased intrinsic dissolution rates (IDRs) were both observed in these non-recrystallized co-amorphous systems. The moisture changes of the systems during storage and the possible drug-co-former molecular interactions showed no effect on the dissolution changes, while phase separation might play a role in it. In conclusion, more attention should be paid to the dissolution changes of co-amorphous systems during storage. Focusing on the initial dissolution behaviors after sample preparation and the physical recrystallization during storage is not enough for the development of co-amorphous systems in future. [Display omitted] [ABSTRACT FROM AUTHOR]

This study aimed to develop microspheres using water-soluble carriers and surfactants to improve the solubility, dissolution, and oral bioavailability of rivaroxaban (RXB). RXB-loaded microspheres with optimal carrier (poly(vinylpyrrolidone) K30, PVP) and surfactant (sodium lauryl sulfate (SLS)) ratios were prepared. 1 H NMR and Fourier transform infrared (FTIR) analyses showed that drug-excipient and excipient-excipient interactions affected RXB solubility, dissolution, and oral absorption. Therefore, molecular interactions between RXB, PVP, and SLS played an important role in improving RXB solubility, dissolution, and oral bioavailability. Formulations IV and VIII, containing optimized RXB/PVP/SLS ratios (1:0.25:2 and 1:1:2, w/w/w), had significantly improved solubility by approximately 160- and 86-fold, respectively, compared to RXB powder, with the final dissolution rates improved by approximately 4.5- and 3.4-fold, respectively, compared to those of RXB powder at 120 min. Moreover, the oral bioavailability of RXB was improved by 2.4- and 1.7-fold, respectively, compared to that of RXB powder. Formulation IV showed the highest improvement in oral bioavailability compared to RXB powder (AUC, 2400.8 ± 237.1 vs 1002.0 ± 82.3 h·ng/mL). Finally, the microspheres developed in this study successfully improved the solubility, dissolution rate, and bioavailability of RXB, suggesting that formulation optimization with the optimal drug-to-excipient ratio can lead to successful formulation development.

The purpose of this study was to elucidate the lack of supersaturation behavior in the dissolution profile of prazosin hydrochloride (PRZ-HCl) in the compendial dissolution test. The equilibrium solubility was measured by a shake-flask method. Dissolution tests were performed by a compendial paddle method with a phosphate buffer solution (pH 6.8, 50 mM phosphate). The solid form of the residual particles was identified by Raman spectroscopy. In the pH range below 6.5, the equilibrium solubility in phosphate buffer was lower than that in the unbuffered solutions (pH adjusted by HCl and NaOH). Raman spectra showed that the residual solid was a phosphate salt of PRZ. In the pH range above 6.5, the pH-solubility profiles in the phosphate buffer solutions and the unbuffered solutions were the same. The residual solid was a PRZ freebase (PRZ-FB). In the dissolution test, PRZ-HCl particles first changed to a phosphate salt within 5 min, then gradually changed to PRZ-FB after several hours. Since the intestinal fluid is buffered by the bicarbonate system in vivo, the dissolution behavior in vivo may not be properly evaluated using a phosphate buffer solution. For drugs with a low phosphate solubility product, it is necessary to consider this aspect., (Copyright © 2023 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.)

• Measurement of solubility data for PCM, salicylic acid and 5-ASA in PEGDME 250 + water mixtures. • Surveying the effect of temperature and cosolvent mass fraction on the drug solubility. • Observing a 1057-fold increase in solubility of salicylic acid in neat PEGDME 250 at 313.15 K. • Correlation of drug solubility data by some cosolvency and activity coefficients models. • Identification of two dominant entropy and enthalpy mechanisms depending on type of drug. The present study reports the solubilization power of polyethylene glycol dimethyl ether 250 (PEGDME 250) for three poorly water-soluble drugs including 5-aminosalicylic acid, salicylic acid and paracetamol in water medium at 293.15 K to 313.15 K under atmospheric pressure (≈85 kPa) by shake-flask technique followed by spectroscopy. The descending order of the mole fraction solubility of drugs in PEGDME 250 + water solutions as follow: 5-aminosalicylic acid < paracetamol < salicylic acid. It was also found that the solubility of 5-aminosalicylic acid, salicylic acid and paracetamol in this system enhanced with raising temperature and PEGDME 250 mass fraction. The obtained data were fitted using Jouyban-Acree based models, the modified Wilson-van't Hoff, NRTL, Wilson and UNIQUAC models. The average relative deviations for the back-calculated solubility data were calculated for reporting the accuracy of each model. Moreover, the apparent thermodynamic properties of dissolution and mixing of drugs in PEGDME 250 + water mixtures such as Gibbs free energy, entropy and enthalpy were determined by the help of solubility data, van't Hoff and Gibbs equations. An endothermic and entropy-driven dissolution process was observed for paracetamol and salicylic acid in PEGDME 250 + water mixtures whereas it was endothermic and enthalpy-driven for the mesalazine in the investigated mixtures. [ABSTRACT FROM AUTHOR]

Formulating poorly soluble drugs with polymers in the form of solid dispersions has been widely used for improving drug dissolution. Endogenous surface-active species present in the gut, such as bile salts, lecithin and other phospholipids, have been shown to play a key role in facilitating lipids and poorly soluble drugs solubilisation in the gut. In this study, we examined the possible occurrence of interactions between a model bile salt, sodium taurocholate (NaTC), and model spray dried solid dispersions comprising piroxicam and Hydroxypropyl Methylcellulose (HPMC), a commonly used hydrophilic polymer for solid dispersion preparation. Solubility measurements revealed the good solubilisation effect of NaTC on the crystalline drug, which was enhanced by the addition of HPMC, and further boosted by the drug formulation into solid dispersion. The colloidal behaviour of the solid dispersions upon dissolution in biorelevant media, with and without NaTC, revealed the formation of NaTC-HPMC complexes and other mixed colloidal species. Cellular level drug absorption studies obtained using Caco-2 monolayers confirmed that the combination of drug being delivered by solid dispersion and the presence of bile salt and lecithin significantly contributed to the improved drug absorption. Together with the role of NaTC-HPMC complexes in assisting the drug solubilisation, our results also highlight the complex interplay between bile salts, excipients and drug absorption. [Display omitted] • The impact of NaTC-HPMC interaction on drug solubilisation and uptake is studied. • Interaction and competition among solubilizing species control drug solubilisation. • NaTC-HPMC and other nanoaggregates are probed by light scattering and Cryo-EM. • Caco-2 uptake studies show nanoaggregates impact on drug absorption. [ABSTRACT FROM AUTHOR]