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A sensitive, selective, precise and stability indicating a high-performance thin layer chromatographic method for the analysis of rufinamide (Rf) in bulk drug and its formulations was developed and validated. The method employed thin layer chromatography aluminum plates precoated with silica gel 60 F254 as the stationary phase. The solvent system consisted of chloroform : methanol : glacial acetic acid (9 : 1 : 0.1 v/v/v). This system was found to give compact spots for Rf (Rf value of 0.68 ± 0.02). Rf was subjected to acid and alkali hydrolysis, oxidation, photodegradation and dry heat treatment. Also, the degraded products were well separated from the pure drug. Densitometric analysis of Rf was carried out in the absorbance mode at 210 nm, which is wavelength maxima for the degradant. The linear regression data for the calibration plots showed a good linear relationship with an r(2) of 0.9989 in the concentration range of 1,000-3,500 ng. The method was validated for precision, accuracy, ruggedness and recovery. The limits of detection and quantitation were 196.59 and 595.74 ng spot(-1), respectively. The drug undergoes degradation under acidic and basic conditions. All the peaks of degraded products were resolved from the standard drug with significantly different Rf values.

A simple and sensitive high-performance thin-layer chromatography (HPTLC) method has been developed for the quantitative estimation of gatifloxacin and ornidazole in its combined dosage forms. Gatifloxacin and ornidazole were chromatographed on silica Gel 60 F(254) TLC plate using n-butanol:methanol:ammonia (6 M) (8:1:1.5 v/v) as the mobile phase and scanned at 302 nm using a Camag TLC Scanner 3. The R(f) value of gatifloxacin and ornidazole was found to be 0.21 +/- 0.02 and 0.76 +/- 0.04, respectively. The linearity of gatifloxacin and ornidazole were in the range of 100 - 500 ng/spot and 250 - 1250 ng/spot, respectively. The limit of detection was found to be 40 ng/spot for gatifloxacin and 100 ng/spot for ornidazole. The proposed method was applied for the determination of gatifloxacin and ornidazole in combined dosage forms.

Developinga drug product with desirable bioavailability is a challenge for sparinglywater soluble drugs such as Fexofinadine hydrochloride. Objective: In the present investigation self microemulsifying drugdelivery system (SMEDDS) of Fexofenadine hydrochloride was developed forimproving solubility and dissolution rate of drug. Material Method: Solubility of Fexofenadine hydrochloride wasdetermined in various non-aqueous vehicles such as oils, surfactants, andco-surfactants. Psuedoternary phase diagrams were constructed to identify theself-micro emulsification region. Four formulations of SMEDDS were selected fromthe optimum concentration of oils, surfactant, and co-surfactants from psuedoternary diagrams. Resultsand Discussion: Selected formulations were evaluated for droplet size,in-vitro drug dissolution, drug content and solubility of drug. The optimumformulation was 20% oleic acid, 26.3% ACONON MC8 and 53.3% PEG 400. Self-microemulsification with the combination of oleic acid and ACONON MC8 was foundhigher. Conclusion: The resultsobtained from in vitro dissolutionindicated Fexofenadine hydrochloride in SMEDDS dissolved rapidly and completelyin phosphate buffer pH 6.8 which was used as dissolution medium.

Liquisolid technique has been widely used to enhance the dissolution of poorly water soluble drugs. The present investigation is on formulation of liquisolid tablets of fenofibrate, a lipid lowering agent. Liquisolid formulation was prepared by applying central composite design (CCD) to optimize various formulation parameters. Amounts of PEG 600 (X 1 ), Avicel PH 102 (X 2 ), and Aerosil 200 (X 3 ) were selected as independent variables while the angle of repose, hardness, disintegration time, and T 90% (time required to release 90% drug) of liquisolid tablets were selected as dependent variables. Optimization of formulation was done by multiple linear regression analysis. The results indicated amounts of PEG 600 and Aviel PH 102 show greater effect on dependant variables. In vitro dissolution of fenofibrate in liquisolid formulations was enhanced compared to the pure form. To conclude, Liquisolid technique is a promising strategy in improving dissolution of poorly water soluble fenofibrate.

Background Oxcarbazepine (OXZ) is an antiepileptic drug used to treat partial seizures. OXZ is available in dosage forms of tablet (150, 300, and 600 mg) and suspension (300 mg in 5 ml) in India. Children and adults complain that the suspension form has a downside in its stability (8 weeks). Aims The aim of the present investigation was to develop a microemulsion (ME) of OXZ for enhanced solubility and stability of drug in product. Materials and methods An ME comprises isopropyl myristate (oil phase), aerosol OT (a bipolar surfactant), and an aqueous phase comprising ethanol and distilled water in a ratio of 2: 8. Various ratios of oil: surfactant (1: 9 to 9: 1) were taken and the amount of aqueous phase titrated was determined using the water titration method. The data were plotted in a pseudoternary phase diagram and an optimized batch was selected. The batch was characterized by droplet size determination, zeta potential, drug content, and in-vitro dissolution studies. Results Size of the globules was found to be 53.65 and 59.15 nm in both ME 1 and ME 2, respectively; thus, it can also be termed as nanoemulsion. Zeta potential shows that the formulation is stable as it has positive zeta, giving 6.13 and 5.21 mV as zeta for ME 1 and ME 2, respectively. pH and conductance were also close to neutral, and hence the system was biocompatible. Conclusion Finally, on the basis of physicochemical characterization and stability studies, it can be concluded that water-in-oil ME for OXZ will serve as a novel drug delivery system with increased solubilization capacity and increased stability.

Hyperlipidemia is considered one of the key factors for cardiovascular diseases. Based on earlier work on a series of 5-alkyl-4-aryl-3-mercapto-(4H)-1,2,4-triazoles, for further lead modification, a series of 4-(substituted)amino-5-substituted-3-mercapto-(4H)-1,2,4-triazoles was designed. Target compounds were synthesized by the well known Hoggarth synthesis of substituted 1,2,4-triazoles. Synthesized compounds were screened for lipid lowering activity using the "Poloxamer 407 induced hyperlipidemia in rats" model at a dose of 100 mg/kg p.o. Compounds were found to alter serum lipid levels significantly. Most of the compounds significantly reduced serum cholesterol and triglyceride levels. Some of the compounds were found to reduce triglycerides and elevate high density lipoprotein (HDL) levels more than the standard drug atorvastatin (CAS 134523-03-8). Compounds with chloro substitution on aryl rings were found more active in reducing serum lipid levels than other substitutions.

A simple, precise, and accurate isocratic RP-HPLC method was developed and validated for determination of eprosartan in bulk drug and tablets. Isocratic RP-HPLC separation was achieved on a Phenomenex C18 column (250 x 4.6 mm id, 5 microm particle size) using the mobile phase 0.5% formic acid-methanol-acetonitrile (80 + 25 + 20, v/v/v, pH 2.80) at a flow rate of 1.0 mL/min. The retention time of eprosartan was 7.64 +/- 0.05 min. The detection was performed at 232 nm. The method was validated for linearity, precision, accuracy, robustness, solution stability, and specificity. The method was linear in the concentration range of 10-400 microg/mL with a correlation coefficient of 0.9999. The repeatability for six samples was 0.253% RSD; the intraday and interday precision were 0.21-0.57 and 0.33-0.71% RSD, respectively. The accuracy (recovery) was found to be in the range of 99.86-100.92%. The drug was subjected to the stress conditions hydrolysis, oxidation, photolysis, and heat. Degradation products produced as a result of the stress conditions did not interfere with detection of eprosartan; therefore, the proposed method can be considered stability-indicating.

The objective of the present investigation was to study the influence of polyethylene glycol 4000 (PEG) and polyvinylpyrrolidone K30 (PVP) on in vitro dissolution of etoricoxib from solid dispersions. Preliminary studies were carried out using a physical mixture of the drug and carriers. Solid dispersions were prepared using the solvent evaporation method. A 32 factorial design was adopted in the solvent evaporation method using the concentration of PEG and PVP as independent variables. Full and reduced models were evolved for dependant variables, such as the percentage of drug release in 10 min (Q10), percentage of drug release in 30 min (Q30), percentage of drug release in 45 min (Q45) and percent dissolution efficiency (DE). The reduced models were validated using two check points. Q1065%, Q3075%, Q4585% and DE80% were used as constraints for the selection of an optimized batch. Contour plots are presented for the selected dependant variables. PEG was found to be more effective in increasing the drug dissolution compared to PVP. Wettability study was carried out for the pure drug and optimized batch. FT-IR spectroscopy, microscopic study, differential scanning calorimetry and X-ray diffraction study were carried out in order to characterize the drug in solid dispersions. Improved dissolution was attributed to decreased crystallinity of the drug, improved wetting and solubilizing effects of carriers such as PEG and PVP from the solid dispersion of etoricoxib. In conclusion, dissolution of etoricoxib can be modulated using appropriate levels of hydrophilic carriers.

A rapid LC-MS/MS method has been developed and validated for the determination of losartan (LOS) and its metabolite losartan acid (LA) (EXP-3174) in human plasma using multiplexing technique (two HPLC units connected to one MS/MS). LOS and LA were extracted from human plasma by SPE technique using Oasis HLB cartridge without evaporation and reconstitution steps. Hydroflumethiazide (HFTZ) was used as an internal standard (IS). The analytes were separated on Zorbax SB C-18 column. The mass transition [M-H] ions used for detection were m/z 421.0 --> 127.0 for LOS, m/z 435.0 --> 157.0 for LA, and m/z 330.0 --> 239.0 for HFTZ. The proposed method was validated over the concentration range of 2.5-2000 ng/mL for LOS and 5.0-3000 ng/mL for LA with correlation coefficient > or = 0.9993. The overall recoveries for LOS, LA, and IS were 96.53, 99.86, and 94.16%, respectively. Total MS run time was 2.0 min/sample. The validated method has been successfully used to analyze human plasma samples for applications in 100 mg fasted and fed pharmacokinetic studies.

Two simple and accurate methods for the determination of pitavastatin calcium (PIT) in tablet dosage forms were developed and validated using column liquid chromatography (LC) and UV spectrophotometry. The LC separation was achieved on a Phenomenex Luna C18 column (250 mm, 4.6 mm id, 5 microm) in the isocratic mode using acetonitrile-water-triethylamine (80 + 19.8 + 0.2, v/v/v), adjusted to pH 3.5 +/- 0.05 with orthophosphoric acid, as the mobile phase at a flow rate of 1.5 mL/min. The retention time was 5.70 min. Both the methods were performed at 238 nm, the wavelength of maximum absorbance of PIT in methanol. In the LC method, quantification was achieved with a photodiode array detector over the concentration range of 0.1-2.5 microg/mL with a mean recovery of 100.26 +/- 0.75%. In the UV method, quantification was achieved over the concentration range of 2-20 microg/mL with mean recovery of 99.65 +/- 1.24%. Both methods were validated, and the results were compared statistically. They were found to be simple, specific, accurate, and precise. The methods were successfully applied for the determination of PIT in tablet dosage form without any interference from common excipients.

High density lipoprotein (HDL) has proven its role in reverse cholesterol transport and cellular cholesterol efflux thus acting as a protective factor against atherogenic cardiovascular diseases. The article focuses primarily on structure and function of genes influencing HDL metabolism. Various novel targets involve liver X receptor, retinoid X receptor, peroxisome proliferators activated receptor agonists and apoA-I mimetics. New molecules targeting these nuclear receptors are described. Phospholipid transfer protein and scavenger receptor B1 are also attractive targets in HDL metabolism. ATP-Binding Cassette transporter A1 and several lipases also play a crucial role in HDL metabolism and are very useful target for atherogenic dyslipidemia. Cholesteryl ester transfer protein inhibitors have shown great promise as possible drug candidates of future. Notably, JTT-705 (Japan Tobacco, Roche) is of great interest in spite of withdrawal of torcetrapib. Considering modest effect of currently available therapeutic options on HDL, these novel HDL elevating targets are doubtlessly the target for future atherosclerotic intervention.

Simple, sensitive high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) methods are developed for the quantitative estimation of rabeprazole and mosapride in their combined pharmaceutical dosage forms. In HPLC, rabeprazole and mosapride are chromatographed using 0.01M 6.5 pH ammonium acetate buffer-methanol-acetonitrile (40:20:40, v/v, pH 5.70+/-0.02) as the mobile phase at a flow rate of 1.0 mL/min. In TLC, the mobile phase is ethyl acetate-methanol-benzene (2:0.5:2.5, v/v). Both the drugs are scanned at 276 nm. The retention times of rabeprazole and mosapride are found to be 4.93+/-0.01 and 9.79+/-0.02, respectively. The Rf values of rabeprazole and mosapride are found to be 0.42+/-0.02 and 0.61+/-0.02, respectively. The linearities of rabeprazole and mosapride are in the range of 400-2000 ng/mL and 300-1500 ng/mL, respectively, for HPLC; in TLC, the linearities of rabeprazole and mosapride are in the range of 400-1200 ng/spot and 300-900 ng/spot, respectively. The limit of detection is found to be 97.7 ng/mL for rabeprazole and 97.6 ng/mL for mosapride in HPLC; in TLC the limit of detection is found to be 132.29 ng/spot for rabeprazole and 98.25 ng/spot for mosapride. The proposed methods can be applied to the determination of rabeprazole and mosapride in combined pharmaceutical products.

This paper describes validated high-performance liquid chromatographic (LC) and high-performance thin-layer chromatographic (TLC) methods for the simultaneous estimation of olanzapine and fluoxetine in pure powder and tablet formulations. The LC separation was achieved on a Lichrospher 100 RP-180, C18 column (250 mm, 4.0 mm id, 5 microm) using 0.05 M potassium dihydrogen phosphate buffer (pH 5.6 adjusted with o-phosphoric acid)-acetonitrile (50 + 50, v/v) as the mobile phase at a flow rate of 1 mL/min and ambient temperature. The TLC separation was achieved on aluminum sheets coated with silica gel 60F254 using methanol-toluene (40 + 20, v/v) as the mobile phase. Quantitation was achieved by measuring ultraviolet absorption at 233 nm over the concentration range of 10-70 and 40-280 microg/mL with mean recovery of 99.54 +/- 0.89 and 99.73 +/- 0.58% for olanzapine and fluoxetine, respectively, by the LC method. Quantitation was achieved by measuring ultraviolet absorption at 233 nm over the concentration range of 100-800 and 400-3200 ng/spot with mean recovery of 101.53 +/- 0.06 and 101.45 +/- 0.35% for olanzapine and fluoxetine, respectively, by the TLC method with densitometry. These methods are simple, precise, and sensitive, and they are applicable for simultaneous determination of olanzapine and fluoxetine in tablet formulations.

This paper describes validated high-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) methods for the simultaneous estimation of pantoprazole (PANT) and domperidone (DOM) in pure powder and capsule formulations. The HPLC separation was achieved on a Phenomenex C18 column (250 mm id, 4.6 mm, 5 pm) using 0.01 M, 6.5 pH ammonium acetate buffer-methanol-acetonitrile (30 + 40 + 30, v/v/v, pH 7.20) as the mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using ethyl acetate-methanol (60 + 40, v/v) as the mobile phase. Quantification was achieved with ultraviolet (UV) detection at 287 nm over the concentration range 400-4000 and 300-3000 ng/mL with mean recovery of 99.35+/-0.80 and 99.08+/-0.57% for PANT and DOM, respectively (HPLC method). Quantification was achieved with UV detection at 287 nm over the concentration range 80-240 and 60-180 ng/spot with mean recovery of 98.40+/-0.67 and 98.75+/-0.71% for PANT and DOM, respectively (HPTLC method). These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of PANT and DOM in pure powder and capsule formulations.

A series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-one was designed on the basis of the triangular pharmacophoric requirement of histamine H1-receptor antagonists. The designed series was synthesized by cyclo-condensation of monoaryl thiourea with ethyl cyanoacetate in the presence of dry HCl gas to give N1-(substituted aryl)-2-mercaptopyrimidine-4(3H)-one, which on cyclo-condensation with acetylacetone gave the pyridopyrimidinone. Further methylation of the mercapto group at C-2 with methyl iodide followed by nucleophilic displacement of the methylmercapto group by various amines gave the targeted compounds. All the synthesized compounds were screened for histamine H1-receptor antagonistic activity by the in vitro method of inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum using cetirizine as a standard drug. All the compounds exhibited potent histamine H1-receptor antagonistic activity with pA2 values from 7.30- 9.75 (cetirizine, pA2 value 9.40). The potent compounds were screened for their in vivo antihistaminic activity by protection of animal from asphyxic shock. The sedative potential of potent compounds was checked on albino mice by photoactometer and they had comparative sedative potential to the standard drug cetirizine. None of the compound exhibited anticholinergic activity in the in vitro rat ileum model.

The binary system of etoricoxib with beta-cyklodextrin (beta-CD) was prepared by the kneading method. Drug-cyclodextrin interactions in solution were investigated by the phase solubility analysis. Differential scanning calorimetry, infrared spectroscopy, powder X-ray diffractometry and microscopic study were used to characterize the solid state of all binary systems, whereas their dissolution properties were evaluated according to the USP XXIII paddle method. The results indicate partial interaction of the drug with beta-CD in the physical mixture and complete interaction in the kneaded complex. The dissolution of etoricoxib was notably increased as compared to pure drug as well as its physical mixture. The complex showed more than 75% drug released in 30 min.

The binary system of etoricoxib with β-cyclodextrin (β-CD) was prepared by the kneading method. Drug-cyclodextrin interactions in solution were investigated by the phase solubility analysis. Differential scanning calorimetry, infrared spectroscopy, powder X-ray diffractometry and microscopic study were used to characterize the solid state of all binary systems, whereas their dissolution properties were evaluated according to the USP XXIII paddle method. The results indicate partial interaction of the drug with β-CD in the physical mixture and complete interaction in the kneaded complex. The dissolution of etoricoxib was notably increased as compared to pure drug as well as its physical mixture. The complex showed more than 75% drug released in 30 min., Metodom gnječenja pripravljen je binarni sustav etorikoksiba s β-ciklodekstrinom (β-CD). Tijekom 30 minuta iz kompleksa se oslobodilo više od 75% ljekovite tvari, što je značajno više u odnosu na fizičku smjesu etorikoksiba i β-CD ili na čistu ljekovitu tvar. Interakcije lijeka i ciklodekstrina u otopini ispitivane su analizom fazne topljivosti. Za karakterizaciju čvrstog stanja svih binarnih sustava korišteni su diferencijalna pretražna kalorimetrija, infracrvena spektroskopija, difrakcija rentgenskih zraka na praškastom uzorku i mikroskopija. Oslobađanje je praćeno metodom lopatice prema USP XXIII. Rezultati ukazuju na djelomičnu interakciju ljekovite tvari s β-CD u fizičkoj smjesi i potpunu interakciju u kompleksu.

Background Traditionally, fruits of Opuntia elatior Mill. were used for their immunomodulatory and antiasthmatic action. The presence of potentially active nutrients and their multifunctional properties make prickly pear a perfect candidate for the production of phytopharmaceutical products. Objective The objective of the present study was to evaluate the bronchodilatory properties of fruits of O. elatior Mill. Materials and methods The bronchodilatory properties were evaluated using bronchospasm induced by acetylcholine and histamine, anticholinergic action on isolated rat ileum, and antihistaminic action on isolated guinea pig ileum. Result and discussion Bronchodilating effect of fruit juice was dose dependent against spasm induced by acetylcholine and histamine. O. elatior Mill. fruits possess a significant inhibitory effect on rat and guinea pig ileum contraction through antihistaminic and antimuscarinic action. Conclusion This study suggested that fruits of O. elatior Mill. possess a significant inhibitory effect on rat and guinea pig ileum, and betacyanin, an active principle compound in prickly pear, may be responsible for the action.

The objective of the present investigation was to study the influence of polyethylene glycol 4000 (PEG) and polyvinylpyrrolidone K30 (PVP) on in vitro dissolution of etoricoxib from solid dispersions. The preliminary studies were carried out using physical mixture of drug and carriers. The solid dispersions were prepared using the solvent evaporation method. A 32 factorial design was adopted in the solvent evaporation method using the concentration of PEG and PVP as independent variables. Full and reduced models were evolved for dependant variables, such as the percentage of drug release in 10 min (Q10), percentage of drug release in 30 min (Q30), percentage of drug release in 45 min (Q45) and percent dissolution efficiency (DE). The reduced models were validated using two check points. Q10 > 65%, Q30 > 75%, Q45 > 85% and DE > 80% were used as constraints for the selection of an optimized batch. Contour plots are presented for the selected dependant variables. PEG was found to be more effective in increasing the drug dissolution compared to PVP. Wettability study was carried out for pure drug and optimized batch. FT-IR spectroscopy, microscopic study, differential scanning calorimetry and X-ray diffraction study were carried out in order to characterize drug in the solid dispersions. Improved dissolution was attributed to decreased crystallinity of the drug, improved wetting and solubilizing effects of carriers such as PEG and PVP from the solid dispersion of etoricoxib. In conclusion, dissolution of etoricoxib can be modulated using appropriate levels of hydrophilic carriers., U radu je proučavan utjecaj polietilenglikola 4000 (PEG) i polivinilpirolidona K30 (PVP) na in vitro oslobađanje etorikoksiba iz čvrstih disperzija. Preliminarni pokusi provedeni su sa smjesom ljekovite tvari i polimernih nosača. Čvrste disperzije pripravljene su metodom uparavanja otapala. Za ovu metodu razvijen je 32 faktorijalni dizajn koristeći koncentraciju PEG i PVP kao nezavisne varijable. Za zavisne varijable razvijeni su potpuni i reducirani modeli, kao što su postotak oslobođene ljekovite tvari u 10 (Q10), 30 (Q30) ili 45 minuta (Q45) i postotak učinkovitosti oslobađanja (DE). Reducirani modeli su validirani pomoću dviju kontrolnih točaka. Q10 > 65%, Q30 > 80%, Q45 > 85% i DE > 80% su upotrebljeni kao ograničenja za izbor optimirane serije. Prikazane su konturne linije za pojedine zavisne varijable. Oslobađanje lijeka bilo je učinkovitije iz pripravaka s PEG-om. Vlaženje je proučavano za čistu ljekovitu supstanciju i omptimiranu seriju. Za karakterizaciju ljekovite tvari u čvrstim disperzijama korištene su FT-IR spektroskopija, mikroskopske studije, diferencijalna pretražna kalorimetrija i difrakcija rentgenskim zrakama. Povećano oslobađanje posljedica je smanjene kristaliničnosti ljekovite tvari, pojačanog vlaženja i solubilizacijskog učinka polimernih nosača u disperzijama. Može se zaključiti da se oslobađanje etorikoksiba može modulirati promjenom količine hidrofilnih nosača.

A rapid and sensitive high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the quantitative estimation of boswellic acids in formulation containing Boswellia serrata extract (BSE) and 11-keto β-boswellic acid in human plasma. Simple extraction method was used for isolation of boswellic acid from formulation sample and acidified plasma sample. The isolated samples were chromatographed on silica gel 60F254-TLC plates, developed using ternary-solvent system (hexane–chloroform–methanol, 5:5:0.5, v/v) and scanned at 260 nm. The linearity range for 11-KBA spiked in 1 ml of plasma was 29.15–145.75 ng with average recovery of 91.66%. The limit of detection and limit of quantification for 11-KBA in human plasma were found to be 8.75 ng/ml and 29.15 ng/ml. The developed method was successfully applied for the assay of market formulations containing BSE and to determine plasma level of 11-keto β-boswellic acid in a clinical pilot study.

Senna is a well-known drug, used in the Ayurvedic and Allopathic systems of medicine, and is a treatment for constipation. The purgative action of senna and its formulations is due to the presence of sennosides A and B. An HPTLC method has been developed for the determination of individual sennosides (A, B, C, D) without any derivatization in marketed formulations (three tablet formulations, two granule formulations and one liquid formulation) and plant materials (senna leaf and pod). The methanolic solution of a sample was applied on a pre-coated silica gel G60 F254 TLC plate (E. Merck.) and was developed using n-propanol: ethyl acetate: water: glacial acetic acid (3:3:2:0.1 v/v) as the mobile phase. The relative band speeds (Rf values) obtained were 0.35, 0.25, 0.61, 0.46 for sennosides A, B, C and D, respectively. The densitometric response was monitored at 366 nm. Calibration curves were found to be linear in the concentration ranges 193–1356, 402–2817, 71–497 and 132–927 ng per spot for sennosides A, B, C, and D, respectively. The correlation coefficients were found to be 0.9978, 0.9987, 0.9939 and 0.9983 respectively for sennosides A, B, C and D. The result obtained with the HPTLC method for total sennoside content was compared with the results using the pharmacopoeial methods (spectrophotometric (British Pharmacopoeia) and spectrofluorimetric (United States Pharmacopeia) using the ‘F’ test). The results revealed no significant difference in the three different methods for estimation of total sennoside. The proposed HPTLC method was found to be simple, specific, precise, accurate and rapid. It can be used for routine quality control of sennosides or senna-containing formulations for individual sennosides.

A rapid, selective and stability-indicating high performance thin layer chromatographic method was developed and validated for the simultaneous estimation of olanzapine and fluoxetine in combined tablet dosage form. Olanzapine and fluoxetine were chromatographed on silica gel 60 F(254) TLC plate using methanol:toluene (4:2 v/v) as the mobile phase and spectrodensitometric scanning-integration was performed at a wavelength of 233 nm using a Camag TLC Scanner III. This system was found to give compact spots for both olanzapine (R(f) value of 0.63+/-0.01) and fluoxetine (R(f) value of 0.31+/-0.01). The polynomial regression data for the calibration plots showed good linear relationship with r(2)=0.9995 in the concentration range of 100-800 ng/spot for olanzapine and 1000-8000 ng/spot for fluoxetine with r(2)=0.9991. The method was validated in terms of linearity, accuracy, precision, recovery and specificity. The limit of detection and the limit of quantification for the olanzapine were found to be 30 and 100 ng/spot, respectively and for fluoxetine 300 and 1000 ng/spot, respectively. Olanzapine and fluoxetine were degraded under acidic, basic and oxidation degradation conditions which showed all the peaks of degraded product were well resolved from the active pharmaceutical ingredient. Both drugs were not further degraded after thermal and photochemical degradation. The method was found to be reproducible and selective for the simultaneous estimation of olanzapine and fluoxetine. As the method could effectively separate the drugs from their degradation products, it can be employed as a stability-indicating method.

A simple, precise and rapid RP-HPLC method was developed for the estimation of etoricoxib in pharmaceutical dosage forms. The method was carried out on a Kromasil 100, RP-C18 column using a mixture of acetonitrile: methanol: 10mM potassium dihydrogen phosphate (pH 3.0 adjusted with orthophosphoric acid). The detection was carried out at 234 nm using rofecoxib as an internal standard. The linearity was found to be 25 to 400 ng/injection with correlation coefficient of 0.9996. The intra-day and inter-day precision (% RSD) were in the range of 0.28 to1.26 and 0.35 to 1.39, respectively. The percentage recovery was found to be 99.52±1.51 to 100.59±1.16. The result of analysis of marketed formulation was found to be 100.32±0.96 to100.95±0.69. The proposed method was successfully applied for the estimation of etoricoxib in pharmaceutical dosage forms.

Two simple, specific, accurate and precise methods, namely, reverse phase high performance liquid chromatography and high performance thin layer chromatography were developed for estimation of nebivolol hydrochloride in tablet dosage form. For the HPLC method, Lichrospher 100 C-18, 5 µm column consisting of 200×4.6 mm i.d. in isocratic mode, with mobile phase containing 50 mM KH 2 PO 4 buffer (pH 3.0±0.1):acetonitrile: (45:55 v/v) was used. The flow rate was 1.0 ml/min and effluent was monitored at 282 nm. The retention time was found to be 3.76±0.02 min. For the high performance thin layer chromatographic method a Camag system comprising of Linnomat V automatic sample applicator, Hamilton syringe, Camag TLC Scanner-3, Camag Win CAT software with stationary phase precoated silica gel 60F 254 and mobile phase consisting of ethyl acetate:toluene:methanol: ammonium hydroxide (1:6:2:0.1 v/v/v/v) were used. The detection of spot was carried out at 282 nm. The R f value was found to be 0.33±0.02. The methods were validated in terms of linearity, accuracy and precision. The linearity curves were found to be linear over 10-150 µg/ml for high performance thin layer chromatography and 100-600 ng/spot for high performance thin layer chromatography. The limit of detection and limit of quantification for high performance thin layer chromatography were found to be 2.0 and 10 µg/ml, respectively, and for the high performance thin layer chromatography, 30 and 100 ng/spot, respectively. The proposed methods were successfully used for estimation of nebivolol hydrochloride in tablet dosage form.

Two simple, rapid, accurate and economical methods have been developed for the simultaneous estimation of metformin and repaglinide in the synthetic mixture. The linearity was observed in the concentration range of 4-24 µg/ml for the both metformin and repaglinide. First method is based on the simultaneous equations, absorbances of both the drugs were determined at 240 nm (λ max of metformin) and at 291.5 nm (λ max of repaglinide). Metformin does not show any absorbance at 291.5 nm, hence its absorptivity was taken zero in the calculation. The method was validated in terms of accuracy (99.24±0.99, 100.98±0.89) and precision (intra-day variations 0.58-1.21, 2.12-3.12 and inter-day variations 0.62-1.42, 2.20-3.08). Second method is based on Q-absorbance ratio; absorbances of both the drugs were determined at 240 nm (l max of metformin) and at isoabsorptive point (254.8 nm). Q-absorption ratio method was validated in terms of accuracy (98.57±1.05, 98.62±1.2402) and precision (intra-day variations 0.58-1.21, 1.01-3.53 and inter-day variations 0.62-1.42, 1.15-3.74). The proposed methods were found accurate, reproducible and economical for the routine analysis of both the drugs in the synthetic mixture.

A simple and sensitive spectrophotometric method has been developed for determination of azithromycin in its pharmaceutical dosage forms. In the proposed method, azithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone, in the presence of ammonium acetate. A yellow coloured chromogen was obtained, having an absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml, with regression coefficient of 0.9978. Various reaction parameters such as concentration of potassium permanganate and reagent, time required for oxidation, and maximum colour intensity were optimized. The method was validated, and can be used successfully to assay azithromycin in its pharmaceutical dosage forms viz. tablets, capsules, and injections.

A simple and sensitive spectrophotometric method has been developed for the estimation of lomefloxacin hydrochloride in its marketed formulations. The method is based on the reaction between the drug and the dichlone, in the presence of crotonaldehyde in dimethylsulfoxide, which produces a blue chromogen with absorption maximum at 645 nm. The good agreement with Beer's law was found in the concentration range of 5-100 µg/ml. The optimum reaction conditions and other analytical parameters are evaluated. Statistical comparison of the results with those of reported method shows good agreement, and indicated no significant difference in precision. The proposed method was found to be simple, accurate, and reproducible for the routine analysis of the drug in pharmaceutical dosage forms.

Two simple, specific, accurate and precise methods, namely, reverse phase high performance liquid chromatography and high performance thin layer chromatography were developed for estimation of carvedilol in bulk drug and pharmaceutical formulations. For the high performance liquid chromatography method, Lichrospher 100 C-18, 5 µm column consisting of 200×4.6 mm i.d. in isocratic mode, with mobile phase containing 50 mM KH2PO4 buffer (pH 3.0±0.1): acetonitrile: methanol (60:50:10 v/v/v) was used. The flow rate was 1.0 ml/min and effluent was monitored at 242 nm. The retention time was 4.56±0.03 min. For the high performance thin layer chromatography method a Camag high performance thin layer chromatography system comprising of Linnomat V automatic sample applicator, Hamilton Syringe, Camag TLC Scanner-3, Camag Win CAT software with stationary phase precoated silica gel 60F254 and mobile phase consisting of ethyl acetate: toluene: methanol (1:4:3.5 v/v/v). The detection of spot was carried out at 242 nm. The Rf value was 0.65±0.02. The methods were validated in terms of linearity, accuracy and precision. The linearity curves were found to be linear over 1-35 µg/ml for high performance liquid chromatography and 50-300 ng/spot for high performance thin layer chromatography. The limit of detection and limit of quantification for high performance liquid chromatography were found to be 0.2 and 0.85 µg/ml, respectively, and for high performance thin layer chromatography, 10 and 35 ng/spot, respectively. The proposed methods were successfully used to determine the drug content of marketed formulations.

A simple and sensitive spectrophotometric method has been developed for determination of betaxolol hydrochloride in bulk powder, and its pharmaceutical dosage forms. In the proposed method, betaxolol is oxidized with sodium periodate, to liberate formaldehyde, which is determined in situ, using acetyl acetone in the presence of ammonium acetate. A yellow coloured chromogen was obtained having absorption maxima at 405 nm. The method is found to be linear in the concentration range of 5-30 µg/ml, with a regression co-efficient of 0.9997. No significant difference was found between the proposed method and official method, when one tailed and two tailed t-test are applied. Various reaction parameters such as concentration of sodium hydroxide and sodium periodate, time required for oxidation, reagent concentration, and time for maximum colour intensity were optimized. The method was validated, and can be used successfully to assay betaxolol in bulk powder, and its pharmaceutical dosage forms viz. ophthalmic solutions.

A simple and sensitive spectrophotometric method has been developed for determination of roxithromycin in its pharmaceutical dosage forms. In the proposed method, roxithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone in the presence of ammonium acetate to give a yellow-coloured chromogen with absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml with regression coefficient of 0.9987. No significant difference was found between the proposed method and the reported method when two-tailed t-tests are applied. Various reaction parameters, such as concentration of potassium permanganate and reagent, time required for oxidation and maximum colour intensity, were optimized. The method was validated and can be used successfully to assay roxithromycin in its pharmaceutical dosage form, viz, tablets.