In recent years, researchers have been working extensively on various novel properties of polymer... more In recent years, researchers have been working extensively on various novel properties of polymers to develop increased efficiency of drug delivery and improve bioavailability of various drug molecules, especially macromolecules. Chitosan, a naturally occurring polysaccharide, because of its protonated/polymeric nature, provides effective and safe absorption of peptide and protein drugs. Its transmucosal absorption is, however, limited to acidic media because of its strong intermolecular hydrogen bonds. A new partially quaternized chitosan derivative, N-trimethyl chitosan chloride (TMC), has been synthesized with improved solubility, safety and effectiveness as an absorption enhancer at neutral pH and in aqueous environment. It enhances the absorption, especially of peptide drugs, by reversible opening of tight junctions in between epithelial cells, thereby facilitating the paracellular diffusion of peptide drugs. This derivative thus opens new perspectives as a biomaterial for various pharmaceutical applications/drug delivery systems. This review deals with the potential use of the quaternized chitosan derivative as a permeation enhancer for the mucosal delivery of macromolecular drugs along with its other biomedical applications.
A sensitive, selective, precise and stability indicating high-performance thin-layer chromatograp... more A sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-methanol-acetone (7:1.5:1.5, v/v/v). This system was found to give compact spots for nelfinavir mesylate (R f value of 0.45 ± 0.02). Nelfinavir mesylate was subjected to acid and alkali hydrolysis, oxidation, dry heat treatment and photodegradation. Also the peaks of degraded products were well resolved from the pure drug with significantly different R f values. Densitometric analysis of nelfinavir mesylate was carried out in the absorbance mode at 250 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.999 ± 0.002 in the concentration range of 1000-6000 ng per spot. The mean value of correlation coefficient, slope and intercept were 0.999 ± 0.002, 0.014 ± 0.001 and 21.73 ± 1.26, respectively. The method was validated for precision, robustness and recovery. The limits of detection and quantitation were 60 and 140 ng per spot, respectively. Statistical analysis proves that the method is repeatable and selective for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating one.
Journal of pharmaceutical and biomedical analysis, Jan 17, 2014
The analysis of highly polar (often charged) compounds which lack a strong UV absorbing chromopho... more The analysis of highly polar (often charged) compounds which lack a strong UV absorbing chromophore is really challenging. Despite the numerous analytical methods published, the demand for a simple, robust and cheap technique for their analysis still persists. Here, reversed phase (RP) liquid chromatography (LC) with capacitively coupled contactless conductivity detection (C(4)D) was explored for the first time as a possible method for separation and detection of various aminoglycoside (AMG) antibiotics which were taken as typical test compounds: tobramycin (TOB), spectinomycin, streptomycin, amikacin, kanamycin A and kanamycin B. C(4)D was performed using a commercially available as well as a laboratory made cell. As ion-pairing reagents (IPR) four perfluorinated carboxylic acids were used: pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid (NFPA) and pentadecafluorooctanoic acid (PDFOA). 0.125mM NFPA-acetonitrile (ACN) (90:10) or 0.125mM PDFOA-ACN (70:30)...
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2007
Simple, accurate, reproducible, selective, sensitive and cost effective UV-spectrophotometric met... more Simple, accurate, reproducible, selective, sensitive and cost effective UV-spectrophotometric methods were developed and validated for the estimation of trigonelline in bulk and pharmaceutical formulations. Trigonelline was estimated at 265 nm in deionised water and at 264 nm in phosphate buffer (pH 4.5). Beer's law was obeyed in the concentration ranges of 1-20microg mL(-1) (r2=0.9999) in deionised water and 1-24 microg mL(-1) (r2=0.9999) in the phosphate buffer medium. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 4.04 x 10(3)L mol(-1)cm(-1) and 0.0422 microg cm(-2)/0.001A in deionised water; and 3.05 x 10(3)L mol(-1)cm(-1) and 0.0567 microg cm(-2)/0.001A in phosphate buffer media, respectively. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.12 and 0.37 microg mL(-1) in deionised water and 0.13 and 0.40 microg mL(-1) in phosphate buffer medium, respectively. The proposed methods were successfully applied for the determination of trigonelline in pharmaceutical formulations (vaginal tablets and bioadhesive vaginal gels). The results demonstrated that the procedure is accurate, precise, specific and reproducible (percent relative standard deviation <2%), while being simple and less time consuming and hence can be suitably applied for the estimation of trigonelline in different dosage forms and dissolution studies.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2007
New, simple, cost effective, accurate and reproducible UV-spectrophotometric methods were develop... more New, simple, cost effective, accurate and reproducible UV-spectrophotometric methods were developed and validated for the estimation of moxifloxacin in bulk and pharmaceutical formulations. Moxifloxacin was estimated at 296 nm in 0.1N hydrochloric acid (pH 1.2) and at 289 nm in phosphate buffer (pH 7.4). Beer's law was obeyed in the concentration range of 1-12 microg ml(-1) (r2=0.9999) in hydrochloric acid and 1-14 microg ml(-1) (r2=0.9998) in the phosphate buffer medium. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 4.63 x 10(4) l mol(-1) cm(-1) and 9.5 ng cm(-2)/0.001 A in hydrochloric acid; and 4.08 x 10(4) l mol(-1) cm(-1) and 10.8 ng cm(-2)/0.001 A in phosphate buffer media, respectively indicating the high sensitivity of the proposed methods. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.0402, 0.1217 microg ml(-1) in hydrochloric acid and 0.0384, 0.1163 microg ml(-1) in phosphate buffer medium, respectively. The proposed methods were successfully applied for the determination of moxifloxacin in pharmaceutical formulations (tablets, i.v. infusions, eye drops and polymeric nanoparticles). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation <2%), while being simple, cheap and less time consuming and hence can be suitably applied for the estimation of moxifloxacin in different dosage forms and dissolution studies.
In recent years, researchers have been working extensively on various novel properties of polymer... more In recent years, researchers have been working extensively on various novel properties of polymers to develop increased efficiency of drug delivery and improve bioavailability of various drug molecules, especially macromolecules. Chitosan, a naturally occurring polysaccharide, because of its protonated/polymeric nature, provides effective and safe absorption of peptide and protein drugs. Its transmucosal absorption is, however, limited to acidic media because of its strong intermolecular hydrogen bonds. A new partially quaternized chitosan derivative, N-trimethyl chitosan chloride (TMC), has been synthesized with improved solubility, safety and effectiveness as an absorption enhancer at neutral pH and in aqueous environment. It enhances the absorption, especially of peptide drugs, by reversible opening of tight junctions in between epithelial cells, thereby facilitating the paracellular diffusion of peptide drugs. This derivative thus opens new perspectives as a biomaterial for various pharmaceutical applications/drug delivery systems. This review deals with the potential use of the quaternized chitosan derivative as a permeation enhancer for the mucosal delivery of macromolecular drugs along with its other biomedical applications.
Pharmaceutical technologists have been working extensively on various mucoadhesive polymeric syst... more Pharmaceutical technologists have been working extensively on various mucoadhesive polymeric systems to create an intimate and prolonged contact at the site of administration. Chitosan is one of the most promising polymers because of its non-toxic, polycationic biocompatible, biodegradable nature, and particularly due to its mucoadhesive and permeation enhancing properties. Due to its potential importance in controlled drug delivery applications, pharmaceutical scientists have exploited this mucoadhesive polymer. However, chitosan suffers from limited solubility at physiological pH and causes presystemic metabolism of drugs in intestinal and gastric fluids in the presence of proteolytic enzymes. These inherent drawbacks of chitosan have been overcome by forming derivatives such as carboxylated, various conjugates, thiolated, and acylated chitosan, thus providing a platform for sustained release formulations at a controlled rate, prolonged residence time, improved patient compliance by reducing dosing frequency, enhanced bioavailability and a significant improvement in therapeutic efficacy. We have explored the potential benefits of these improved chitosan derivatives in modern drug delivery.
Journal of Liquid Chromatography & Related Technologies, 2007
Page 1. Quantitative Determination and Stress Degradation Studies on a Biomarker Trigonelline by ... more Page 1. Quantitative Determination and Stress Degradation Studies on a Biomarker Trigonelline by a Validated Stability-Indicating HPTLC Method Shruti Chopra, Sanjay K. Motwani, Zeenat Iqbal, Farhan J. Ahmad, and Roop ...
European Journal of Pharmaceutics and Biopharmaceutics, 2007
The present research work aimed at development and optimisation of mucoadhesive polyherbal gels (... more The present research work aimed at development and optimisation of mucoadhesive polyherbal gels (MPG) for vaginal drug delivery. As the rheological and mucoadhesive properties of the gels correlate well to each other the prepared MPGs were optimised for maximum mucoadhesion using a relationship between the storage modulus (G 0 ) and Gel Index (GI), by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the polymer concentration (X 1 ), honey concentration (X 2 ) and aerosil concentration (X 3 ). Aerosil has been investigated for the first time to improve the consistency of gels. The dependent variables studied were the elastic modulus, G 0 (Y 1 ), gel index (Y 2 ), and maximum detachment force (Y 3 ) with applied constraints of 500 6 Y 1 6 700 and 4 6 Y 2 6 5. Response surface plots were drawn, statistical validity of the polynomials was established and optimised formulations was selected by feasibility and grid search. Three types of Carbopol studied were Carbopol 934P, Carbopol 974P and Polycarbophil. In vitro release studies were carried out for the optimised formulations and the data were fitted to release kinetics equations. Validation of the optimisation study with 8 confirmatory runs indicated high degree of prognostic ability of response surface methodology. Gels showed a gradual sustained release by a non-Fickian diffusion process. Incorporation of aerosil to gels was found to improve the rheological and mucoadhesion properties by about 50-54% and 7-11%, respectively. The Box-Behnken design facilitated the optimisation of polyherbal gel formulations for enhanced vaginal drug delivery by optimum mucoadhesion and longer retention.
European Journal of Pharmaceutics and Biopharmaceutics, 2007
The aim of the present research work was to systemically device a model of factors that would yie... more The aim of the present research work was to systemically device a model of factors that would yield an optimized sustained release dosage form of an anti-hypertensive agent, losartan potassium, using response surface methodology by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the amount of the release retardant polymers -HPMC K15M (X 1 ), HPMC K100M (X 2 ) and sodium carboxymethyl cellulose (X 3 ). The dependent variables were the burst release in 15 min (Y 1 ), cumulative percentage release of drug after 60 min (Y 2 ) and hardness (Y 3 ) of the tablets with constraints on the Y 2 = 31-35%. Statistical validity of the polynomials was established. In vitro release and swelling studies were carried out for the optimized formulation and the data were fitted to kinetic equations. The polynomial mathematical relationship obtained Y 2 ¼ 32:91 À 2:30X 1 À 5:69X 2 À 0:97X 3 À 0:41X 1 X 2 þ 0:21X 1 X 3 À 0:92X 2 1 À 1:89X 2 2 ðr 2 ¼ 0:9944Þ explained the main and quadratic effects, and the interactions of factors influencing the drug release from matrix tablets. The adjusted (0.9842) and predicted values (0.9893) of r 2 for Y 2 were in close agreement. Validation of the optimization study indicated high degree of prognostic ability of response surface methodology. Tablets showed an initial burst release preceding a more gradual sustained release phase following a non-fickian diffusion process. The Box-Behnken experimental design facilitated the formulation and optimization of sustained release hydrophilic matrix systems of losartan potassium.
A stability-indicating reversed-phase high-performance liquid chromatographic method was develope... more A stability-indicating reversed-phase high-performance liquid chromatographic method was developed and validated as per the International Conference on Harmonization (ICH) guidelines to evaluate the reproducibility of batches of synthetic peptides included in a stability program, in particular cholecystokinin (CCK-4) peptide.
Introduction -The surge of interest in naturally occurring phytochemicals with anticancer potenti... more Introduction -The surge of interest in naturally occurring phytochemicals with anticancer potential has led to the discovery of many molecules, one of them being thymoquinone (TQ) the bioactive constituent of the volatile oil of black seed, Nigella sativa L. (NS). Objective -The aim of the present work was to develop and validate an HPTLC method for determination of TQ in NS extracts, commercially available marketed oils, polyherbal formulations and in lipid-based oral and parenteral formulations prepared in-house. Methodology -Analysis of TQ was performed on TLC aluminium plates pre-coated with silica gel 60F-254. Linear ascending development was carried out in twin trough glass chamber, saturated with mobile phase consisting of toluene-cyclohexane (8 : 2, v/v) at ambient temperature. Camag TLC scanner III was used for the spectrodensitometric scanning and analysis in absorbance mode at 254 nm. Results -The method was found to give compact spots for TQ (Rf value of 0.28 Ϯ 0.05) and was linear over the range 100-1400 ng/spot (r 2 = 0.9921 Ϯ 0.0020). Accuracy, precision and repeatability were all within the required limits. The mean recoveries measured at three concentrations were higher than 95% with RSD Յ 3%. Conclusion -The HPTLC method developed was found to be relatively simple, rapid and accurate for the routine analysis of TQ in extracts, marketed oils, polyherbal and in-house formulations.
A sensitive, selective, precise and stability indicating high-performance thin-layer chromatograp... more A sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-methanol-acetone (7:1.5:1.5, v/v/v). This system was found to give compact spots for nelfinavir mesylate (R f value of 0.45 ± 0.02). Nelfinavir mesylate was subjected to acid and alkali hydrolysis, oxidation, dry heat treatment and photodegradation. Also the peaks of degraded products were well resolved from the pure drug with significantly different R f values. Densitometric analysis of nelfinavir mesylate was carried out in the absorbance mode at 250 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.999 ± 0.002 in the concentration range of 1000-6000 ng per spot. The mean value of correlation coefficient, slope and intercept were 0.999 ± 0.002, 0.014 ± 0.001 and 21.73 ± 1.26, respectively. The method was validated for precision, robustness and recovery. The limits of detection and quantitation were 60 and 140 ng per spot, respectively. Statistical analysis proves that the method is repeatable and selective for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating one.
European Journal of Pharmaceutics and Biopharmaceutics, 2007
Management of extraocular disease is mainly limited by the inability to provide long-term extraoc... more Management of extraocular disease is mainly limited by the inability to provide long-term extraocular drug delivery without avoiding the systemic drug exposure and/or affecting the intraocular structures and poor availability of drugs, which may be overcome by prolonging the contact time with the ocular surface, for instance with bioadhesive polymers. In the present study, mucoadhesive chitosan (CS)-sodium alginate (ALG) nanoparticles were investigated as a new vehicle for the prolonged topical ophthalmic delivery of antibiotic, gatifloxacin. A modified coacervation or ionotropic gelation method was used to produce gatifloxacin-loaded submicroscopic nanoreservoir systems. It was optimised using design of experiments by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the amount of the bioadhesive polymers: CS, ALG and the amount of drug in the formulation. The dependent variables were the particle size, zetapotential, encapsulation efficiency and burst release. Response surface plots were drawn, statistical validity of the polynomials was established and optimised formulations were selected by feasibility and grid search. Nanoparticles were characterised by FT-IR, DSC, TEM and atomic force microscopy. Drug content, encapsulation efficiency and particle properties such as size, size distribution (polydispersity index) and zetapotential were determined. The designed nanoparticles have average particle size from 205 to 572 nm (polydispersity from 0.325 to 0.489) and zetapotential from 17.6 to 47.8 mV. Nanoparticles revealed a fast release during the first hour followed by a more gradual drug release during a 24-h period following a non-Fickian diffusion process. Box-Behnken experimental design thus facilitated the optimisation of mucoadhesive nanoparticulate carrier systems for prolonged ocular delivery of the drug.
In recent years, researchers have been working extensively on various novel properties of polymer... more In recent years, researchers have been working extensively on various novel properties of polymers to develop increased efficiency of drug delivery and improve bioavailability of various drug molecules, especially macromolecules. Chitosan, a naturally occurring polysaccharide, because of its protonated/polymeric nature, provides effective and safe absorption of peptide and protein drugs. Its transmucosal absorption is, however, limited to acidic media because of its strong intermolecular hydrogen bonds. A new partially quaternized chitosan derivative, N-trimethyl chitosan chloride (TMC), has been synthesized with improved solubility, safety and effectiveness as an absorption enhancer at neutral pH and in aqueous environment. It enhances the absorption, especially of peptide drugs, by reversible opening of tight junctions in between epithelial cells, thereby facilitating the paracellular diffusion of peptide drugs. This derivative thus opens new perspectives as a biomaterial for various pharmaceutical applications/drug delivery systems. This review deals with the potential use of the quaternized chitosan derivative as a permeation enhancer for the mucosal delivery of macromolecular drugs along with its other biomedical applications.
A sensitive, selective, precise and stability indicating high-performance thin-layer chromatograp... more A sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-methanol-acetone (7:1.5:1.5, v/v/v). This system was found to give compact spots for nelfinavir mesylate (R f value of 0.45 ± 0.02). Nelfinavir mesylate was subjected to acid and alkali hydrolysis, oxidation, dry heat treatment and photodegradation. Also the peaks of degraded products were well resolved from the pure drug with significantly different R f values. Densitometric analysis of nelfinavir mesylate was carried out in the absorbance mode at 250 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.999 ± 0.002 in the concentration range of 1000-6000 ng per spot. The mean value of correlation coefficient, slope and intercept were 0.999 ± 0.002, 0.014 ± 0.001 and 21.73 ± 1.26, respectively. The method was validated for precision, robustness and recovery. The limits of detection and quantitation were 60 and 140 ng per spot, respectively. Statistical analysis proves that the method is repeatable and selective for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating one.
Journal of pharmaceutical and biomedical analysis, Jan 17, 2014
The analysis of highly polar (often charged) compounds which lack a strong UV absorbing chromopho... more The analysis of highly polar (often charged) compounds which lack a strong UV absorbing chromophore is really challenging. Despite the numerous analytical methods published, the demand for a simple, robust and cheap technique for their analysis still persists. Here, reversed phase (RP) liquid chromatography (LC) with capacitively coupled contactless conductivity detection (C(4)D) was explored for the first time as a possible method for separation and detection of various aminoglycoside (AMG) antibiotics which were taken as typical test compounds: tobramycin (TOB), spectinomycin, streptomycin, amikacin, kanamycin A and kanamycin B. C(4)D was performed using a commercially available as well as a laboratory made cell. As ion-pairing reagents (IPR) four perfluorinated carboxylic acids were used: pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid (NFPA) and pentadecafluorooctanoic acid (PDFOA). 0.125mM NFPA-acetonitrile (ACN) (90:10) or 0.125mM PDFOA-ACN (70:30)...
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2007
Simple, accurate, reproducible, selective, sensitive and cost effective UV-spectrophotometric met... more Simple, accurate, reproducible, selective, sensitive and cost effective UV-spectrophotometric methods were developed and validated for the estimation of trigonelline in bulk and pharmaceutical formulations. Trigonelline was estimated at 265 nm in deionised water and at 264 nm in phosphate buffer (pH 4.5). Beer's law was obeyed in the concentration ranges of 1-20microg mL(-1) (r2=0.9999) in deionised water and 1-24 microg mL(-1) (r2=0.9999) in the phosphate buffer medium. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 4.04 x 10(3)L mol(-1)cm(-1) and 0.0422 microg cm(-2)/0.001A in deionised water; and 3.05 x 10(3)L mol(-1)cm(-1) and 0.0567 microg cm(-2)/0.001A in phosphate buffer media, respectively. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.12 and 0.37 microg mL(-1) in deionised water and 0.13 and 0.40 microg mL(-1) in phosphate buffer medium, respectively. The proposed methods were successfully applied for the determination of trigonelline in pharmaceutical formulations (vaginal tablets and bioadhesive vaginal gels). The results demonstrated that the procedure is accurate, precise, specific and reproducible (percent relative standard deviation <2%), while being simple and less time consuming and hence can be suitably applied for the estimation of trigonelline in different dosage forms and dissolution studies.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2007
New, simple, cost effective, accurate and reproducible UV-spectrophotometric methods were develop... more New, simple, cost effective, accurate and reproducible UV-spectrophotometric methods were developed and validated for the estimation of moxifloxacin in bulk and pharmaceutical formulations. Moxifloxacin was estimated at 296 nm in 0.1N hydrochloric acid (pH 1.2) and at 289 nm in phosphate buffer (pH 7.4). Beer's law was obeyed in the concentration range of 1-12 microg ml(-1) (r2=0.9999) in hydrochloric acid and 1-14 microg ml(-1) (r2=0.9998) in the phosphate buffer medium. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 4.63 x 10(4) l mol(-1) cm(-1) and 9.5 ng cm(-2)/0.001 A in hydrochloric acid; and 4.08 x 10(4) l mol(-1) cm(-1) and 10.8 ng cm(-2)/0.001 A in phosphate buffer media, respectively indicating the high sensitivity of the proposed methods. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.0402, 0.1217 microg ml(-1) in hydrochloric acid and 0.0384, 0.1163 microg ml(-1) in phosphate buffer medium, respectively. The proposed methods were successfully applied for the determination of moxifloxacin in pharmaceutical formulations (tablets, i.v. infusions, eye drops and polymeric nanoparticles). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation <2%), while being simple, cheap and less time consuming and hence can be suitably applied for the estimation of moxifloxacin in different dosage forms and dissolution studies.
In recent years, researchers have been working extensively on various novel properties of polymer... more In recent years, researchers have been working extensively on various novel properties of polymers to develop increased efficiency of drug delivery and improve bioavailability of various drug molecules, especially macromolecules. Chitosan, a naturally occurring polysaccharide, because of its protonated/polymeric nature, provides effective and safe absorption of peptide and protein drugs. Its transmucosal absorption is, however, limited to acidic media because of its strong intermolecular hydrogen bonds. A new partially quaternized chitosan derivative, N-trimethyl chitosan chloride (TMC), has been synthesized with improved solubility, safety and effectiveness as an absorption enhancer at neutral pH and in aqueous environment. It enhances the absorption, especially of peptide drugs, by reversible opening of tight junctions in between epithelial cells, thereby facilitating the paracellular diffusion of peptide drugs. This derivative thus opens new perspectives as a biomaterial for various pharmaceutical applications/drug delivery systems. This review deals with the potential use of the quaternized chitosan derivative as a permeation enhancer for the mucosal delivery of macromolecular drugs along with its other biomedical applications.
Pharmaceutical technologists have been working extensively on various mucoadhesive polymeric syst... more Pharmaceutical technologists have been working extensively on various mucoadhesive polymeric systems to create an intimate and prolonged contact at the site of administration. Chitosan is one of the most promising polymers because of its non-toxic, polycationic biocompatible, biodegradable nature, and particularly due to its mucoadhesive and permeation enhancing properties. Due to its potential importance in controlled drug delivery applications, pharmaceutical scientists have exploited this mucoadhesive polymer. However, chitosan suffers from limited solubility at physiological pH and causes presystemic metabolism of drugs in intestinal and gastric fluids in the presence of proteolytic enzymes. These inherent drawbacks of chitosan have been overcome by forming derivatives such as carboxylated, various conjugates, thiolated, and acylated chitosan, thus providing a platform for sustained release formulations at a controlled rate, prolonged residence time, improved patient compliance by reducing dosing frequency, enhanced bioavailability and a significant improvement in therapeutic efficacy. We have explored the potential benefits of these improved chitosan derivatives in modern drug delivery.
Journal of Liquid Chromatography & Related Technologies, 2007
Page 1. Quantitative Determination and Stress Degradation Studies on a Biomarker Trigonelline by ... more Page 1. Quantitative Determination and Stress Degradation Studies on a Biomarker Trigonelline by a Validated Stability-Indicating HPTLC Method Shruti Chopra, Sanjay K. Motwani, Zeenat Iqbal, Farhan J. Ahmad, and Roop ...
European Journal of Pharmaceutics and Biopharmaceutics, 2007
The present research work aimed at development and optimisation of mucoadhesive polyherbal gels (... more The present research work aimed at development and optimisation of mucoadhesive polyherbal gels (MPG) for vaginal drug delivery. As the rheological and mucoadhesive properties of the gels correlate well to each other the prepared MPGs were optimised for maximum mucoadhesion using a relationship between the storage modulus (G 0 ) and Gel Index (GI), by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the polymer concentration (X 1 ), honey concentration (X 2 ) and aerosil concentration (X 3 ). Aerosil has been investigated for the first time to improve the consistency of gels. The dependent variables studied were the elastic modulus, G 0 (Y 1 ), gel index (Y 2 ), and maximum detachment force (Y 3 ) with applied constraints of 500 6 Y 1 6 700 and 4 6 Y 2 6 5. Response surface plots were drawn, statistical validity of the polynomials was established and optimised formulations was selected by feasibility and grid search. Three types of Carbopol studied were Carbopol 934P, Carbopol 974P and Polycarbophil. In vitro release studies were carried out for the optimised formulations and the data were fitted to release kinetics equations. Validation of the optimisation study with 8 confirmatory runs indicated high degree of prognostic ability of response surface methodology. Gels showed a gradual sustained release by a non-Fickian diffusion process. Incorporation of aerosil to gels was found to improve the rheological and mucoadhesion properties by about 50-54% and 7-11%, respectively. The Box-Behnken design facilitated the optimisation of polyherbal gel formulations for enhanced vaginal drug delivery by optimum mucoadhesion and longer retention.
European Journal of Pharmaceutics and Biopharmaceutics, 2007
The aim of the present research work was to systemically device a model of factors that would yie... more The aim of the present research work was to systemically device a model of factors that would yield an optimized sustained release dosage form of an anti-hypertensive agent, losartan potassium, using response surface methodology by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the amount of the release retardant polymers -HPMC K15M (X 1 ), HPMC K100M (X 2 ) and sodium carboxymethyl cellulose (X 3 ). The dependent variables were the burst release in 15 min (Y 1 ), cumulative percentage release of drug after 60 min (Y 2 ) and hardness (Y 3 ) of the tablets with constraints on the Y 2 = 31-35%. Statistical validity of the polynomials was established. In vitro release and swelling studies were carried out for the optimized formulation and the data were fitted to kinetic equations. The polynomial mathematical relationship obtained Y 2 ¼ 32:91 À 2:30X 1 À 5:69X 2 À 0:97X 3 À 0:41X 1 X 2 þ 0:21X 1 X 3 À 0:92X 2 1 À 1:89X 2 2 ðr 2 ¼ 0:9944Þ explained the main and quadratic effects, and the interactions of factors influencing the drug release from matrix tablets. The adjusted (0.9842) and predicted values (0.9893) of r 2 for Y 2 were in close agreement. Validation of the optimization study indicated high degree of prognostic ability of response surface methodology. Tablets showed an initial burst release preceding a more gradual sustained release phase following a non-fickian diffusion process. The Box-Behnken experimental design facilitated the formulation and optimization of sustained release hydrophilic matrix systems of losartan potassium.
A stability-indicating reversed-phase high-performance liquid chromatographic method was develope... more A stability-indicating reversed-phase high-performance liquid chromatographic method was developed and validated as per the International Conference on Harmonization (ICH) guidelines to evaluate the reproducibility of batches of synthetic peptides included in a stability program, in particular cholecystokinin (CCK-4) peptide.
Introduction -The surge of interest in naturally occurring phytochemicals with anticancer potenti... more Introduction -The surge of interest in naturally occurring phytochemicals with anticancer potential has led to the discovery of many molecules, one of them being thymoquinone (TQ) the bioactive constituent of the volatile oil of black seed, Nigella sativa L. (NS). Objective -The aim of the present work was to develop and validate an HPTLC method for determination of TQ in NS extracts, commercially available marketed oils, polyherbal formulations and in lipid-based oral and parenteral formulations prepared in-house. Methodology -Analysis of TQ was performed on TLC aluminium plates pre-coated with silica gel 60F-254. Linear ascending development was carried out in twin trough glass chamber, saturated with mobile phase consisting of toluene-cyclohexane (8 : 2, v/v) at ambient temperature. Camag TLC scanner III was used for the spectrodensitometric scanning and analysis in absorbance mode at 254 nm. Results -The method was found to give compact spots for TQ (Rf value of 0.28 Ϯ 0.05) and was linear over the range 100-1400 ng/spot (r 2 = 0.9921 Ϯ 0.0020). Accuracy, precision and repeatability were all within the required limits. The mean recoveries measured at three concentrations were higher than 95% with RSD Յ 3%. Conclusion -The HPTLC method developed was found to be relatively simple, rapid and accurate for the routine analysis of TQ in extracts, marketed oils, polyherbal and in-house formulations.
A sensitive, selective, precise and stability indicating high-performance thin-layer chromatograp... more A sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-methanol-acetone (7:1.5:1.5, v/v/v). This system was found to give compact spots for nelfinavir mesylate (R f value of 0.45 ± 0.02). Nelfinavir mesylate was subjected to acid and alkali hydrolysis, oxidation, dry heat treatment and photodegradation. Also the peaks of degraded products were well resolved from the pure drug with significantly different R f values. Densitometric analysis of nelfinavir mesylate was carried out in the absorbance mode at 250 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.999 ± 0.002 in the concentration range of 1000-6000 ng per spot. The mean value of correlation coefficient, slope and intercept were 0.999 ± 0.002, 0.014 ± 0.001 and 21.73 ± 1.26, respectively. The method was validated for precision, robustness and recovery. The limits of detection and quantitation were 60 and 140 ng per spot, respectively. Statistical analysis proves that the method is repeatable and selective for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating one.
European Journal of Pharmaceutics and Biopharmaceutics, 2007
Management of extraocular disease is mainly limited by the inability to provide long-term extraoc... more Management of extraocular disease is mainly limited by the inability to provide long-term extraocular drug delivery without avoiding the systemic drug exposure and/or affecting the intraocular structures and poor availability of drugs, which may be overcome by prolonging the contact time with the ocular surface, for instance with bioadhesive polymers. In the present study, mucoadhesive chitosan (CS)-sodium alginate (ALG) nanoparticles were investigated as a new vehicle for the prolonged topical ophthalmic delivery of antibiotic, gatifloxacin. A modified coacervation or ionotropic gelation method was used to produce gatifloxacin-loaded submicroscopic nanoreservoir systems. It was optimised using design of experiments by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the amount of the bioadhesive polymers: CS, ALG and the amount of drug in the formulation. The dependent variables were the particle size, zetapotential, encapsulation efficiency and burst release. Response surface plots were drawn, statistical validity of the polynomials was established and optimised formulations were selected by feasibility and grid search. Nanoparticles were characterised by FT-IR, DSC, TEM and atomic force microscopy. Drug content, encapsulation efficiency and particle properties such as size, size distribution (polydispersity index) and zetapotential were determined. The designed nanoparticles have average particle size from 205 to 572 nm (polydispersity from 0.325 to 0.489) and zetapotential from 17.6 to 47.8 mV. Nanoparticles revealed a fast release during the first hour followed by a more gradual drug release during a 24-h period following a non-Fickian diffusion process. Box-Behnken experimental design thus facilitated the optimisation of mucoadhesive nanoparticulate carrier systems for prolonged ocular delivery of the drug.
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Papers by Shruti Chopra