Sathyanarayana Upadrashta - Academia.edu (original) (raw)

Papers by Sathyanarayana Upadrashta

Research paper thumbnail of Oestrone loaded poly(l-lactic acid) microspheres: preparation, evaluation and in vitro release kinetics

Journal of Microencapsulation, 1993

Poly(l-lactic acid) microspheres containing oestrone were prepared by the solvent evaporation met... more Poly(l-lactic acid) microspheres containing oestrone were prepared by the solvent evaporation method using methylene chloride as the casting solvent and poly(vinyl alcohol) as the emulsifier. Non-agglomerated microspheres with average diameters of 125-160 microns, containing 3-18 per cent oestrone were prepared successfully using a stirring rate of 650 rpm and a poly(vinyl alcohol) concentration as low as 0.15%. Drug loading decreased with an increase in the relative amounts of methylene chloride or emulsifier. Microspheres with 9 per cent loading released approximately 50 per cent of the drug in the first 12 h and the remainder at a much slower rate over several days. Initial examination revealed that the kinetic data followed both a first-order release pattern and the Higuchi matrix model. Differential rate treatment confirmed the Higuchi matrix model and the release mechanism was determined to be diffusion-controlled.

Research paper thumbnail of Development of Matrix Controlled Release Beads by Extrusion-Spheronization Technology Using a Statistical Screening Design

Drug Development and Industrial Pharmacy, 1994

... Sanjay R. Goskondal, Gregory A. Hileman1*2, and Sathyanarayana M. Upadrashtal~~, 1School of P... more ... Sanjay R. Goskondal, Gregory A. Hileman1*2, and Sathyanarayana M. Upadrashtal~~, 1School of Pharmacy, University of Missouri-Kansas City, Kansas City ... Several materials failed in retarding drug release 8. Carnuba wax was an exception, again at low drug concentrations. ...

Research paper thumbnail of Drug Solubility Effects on Predicting Optimum Conditions for Extrusion and Spheronization of Pellets

Pharmaceutical Development and Technology, 1997

This paper explores the utility of aqueous solubility of structurally similar drugs in predicting... more This paper explores the utility of aqueous solubility of structurally similar drugs in predicting optimum conditions for extrusion and spheronization of pellets using response surface methodology. Pharmacologically active xanthine derivatives exhibiting widely varying aqueous solubility were used to determine optimum conditions for pelletization. The amount of water added to the formulation, wet mixing time, and spheronizing time were explored in a series of central composite experimental designs to exhaustively explore and mathematically model the response surfaces for each drug. Using a marketed microcrystalline cellulose excipient, optimum extrusion and spheronization conditions for less soluble drugs required more water, a longer wet mixing time, and prolonged spheronizing times. Results were similar when a new microcrystalline cellulose was substituted, except that more water was required. When comparing results for different drugs, a strong linear relationship was observed between the aqueous solubility of the drug and the water content required for optimum pellet production. The water content range over which quality pellets could be produced was much broader for poorly soluble drugs. Aqueous solubility of the active component appears to be a good predictor for the water requirements for optimum extrusion and spheronization of pellets for pharmaceutical applications.

Research paper thumbnail of Response surface optimization of high dose pellets by extrusion and spheronization

International Journal of Pharmaceutics, 1993

... 03281 Response surface optimization of high dose pellets by extrusion and spheronization Greg... more ... 03281 Response surface optimization of high dose pellets by extrusion and spheronization Gregory A. Hileman '''b, Sanjay R. Goskonda a, Anthony J. Spalitto b and Sathyanarayana M. Upadrashta ... Pellets with roundness scores less than 1.20 ap-pear increasingly more smooth ...

Research paper thumbnail of Equilibrium binding studies of the interaction between anthralin and bovine serum albumin

International Journal of Pharmaceutics, 1989

Abstract The binding of the antipsoriatic drug, anthralin, to calf thymus deoxyribonucleic acid (... more Abstract The binding of the antipsoriatic drug, anthralin, to calf thymus deoxyribonucleic acid (DNA) and bovine serum albumin (BSA) was examined using fluorescence spectroscopy. Results indicated that anthralin did not bind to DNA but did bind to BSA at physiological pH. Job's method of continuous variation indicated that anthralin formed a 1:1 complex with BSA. The investigation employing BSA was conducted at 4 different temperatures, 8.0, 15.4, 25.0 and 34.7°C. Langmuir's one-site model was directly fitted to the data with an iterative non-linear regression program. The thermodynamic parameters derived from the van't Hoff plot were as follows: ΔG = −8.19 kcal/mol, ΔH = −7.85 kcal/mol, and ΔS = +1.12 e.u. On the basis of experimental evidence it is pr that anthralin binds to a tryptophan residue on BSA by a hydrogen bonding mechanism.

Research paper thumbnail of Equilibrium binding studies of the 1,8-dihydroxy-9,10-anthraquinone-bovine serum albumin interaction

International Journal of Pharmaceutics, 1989

The binding of 1,8~ihydroxy-9,10-anthraquinone (DAQ) to bovine serum albumin (BSA) was investigat... more The binding of 1,8~ihydroxy-9,10-anthraquinone (DAQ) to bovine serum albumin (BSA) was investigated using fluorescence spectroscopy. The fluorescence of BSA was quenched following interaction with DAQ and this property was used to generate binding isotherms. Binding studies were conducted at 5 different temperatures: 8.0, 15.4, 25.0, 29.7 and 34.7 o C. The thermodynamic parameters at 2S" C derived from the van't Hoff plot were as follows: AG =-8.03 kcal/mol, AH =-11.8 kcal/mol, and AS =-12.6 e.u. Based on these results it is postulated that DAQ binds to a tryptophan residue on albumin mainly by hydrogen bonding. A statistical technique employing joint confidence ellipsoids has shown that the parameter vectors for anthralin and DAQ are different at the 90% confidence level thus indicating differences in binding affinities. Competitive binding experiments were also conducted and the results indicated that DAQ competitively inhibits the albumin binding of anthralin. In~~uction Recently it has been shown (Upadrashta and Wurster, 1989) that anthrahn, an antipsoriatic agent, binds to bovine serum albumin (BSA). This drug-protein interaction exhibits a 1 : 1 stoichiometry and a binding constant of 1.01 X lo6 M-' (Upadrashta and Wurster, 1989). AnthraIin rapidly decomposes in aqueous solutions (Upadrashta and Wurster, 1988a, Melo et al., 1983) near neutral pH

Research paper thumbnail of Controlled release pellets by extrusion-spheronization

International Journal of Pharmaceutics, 1994

Research paper thumbnail of Ethylcellulose matrix controlled release tablets of a water-soluble drug

International Journal of Pharmaceutics, 1995

Research paper thumbnail of Compressibility and compactibility properties of ethylcellulose

International Journal of Pharmaceutics, 1994

Compaction characteristics of various viscosity grades of ethylcellulose were examined using an i... more Compaction characteristics of various viscosity grades of ethylcellulose were examined using an instrumented tablet press. Four different data analysis techniques were employed to characterize the compactibility and compressibility data: tablet hardness-compression force profiles, ejected tablet Heckei analysis, work calculations from force-displacement data and force-time profile analysis. The calculated parameters derived from these approaches included the following: mean yield pressure from the Heckel analysis, net work and elastic work from the force-displacement data and the area to height (A/H) ratio from force-time data. Lower viscosity grades of ethylcellulose were found to be more compactible as described by tablet hardness-compression force profiles. Lower viscosity grades also exhibited a lower mean yield pressure from the Heckel analysis, indicating greater compressibility. Higher viscosity grades exhibited a decrease in net work and an increase in elastic work. Higher viscosity grades also exhibited greater values for the A/H ratio derived from force-time analysis, indicating lower compressibility. Higher viscosity grades of ethylcellulose showed increases in true density, melting point, and heat of fusion. The variation in compactibility and compressibility properties of different viscosity grades of ethylcellulose can be attributed to changes in the polymer's degree of order.

Research paper thumbnail of Consolidation of ethylcellulose: Effect of particle size, press speed, and lubricants

International Journal of Pharmaceutics, 1995

ABSTRACT

Research paper thumbnail of Spectroscopic Analysis of the Ionization Behavior of Anthralin

Spectroscopy Letters, 1988

Abstract The ionic equilibria of anthralin were examined at 25°C in aqueous solutions varying in ... more Abstract The ionic equilibria of anthralin were examined at 25°C in aqueous solutions varying in pH from 5.10 to 11.74. Despite the presence of three phenol groups, only one pKa was observed under a these experimental conditions and even at pH - 11.74 there was no spectroscopic evidence for the presumed second pKa Possible a causes for this result are discussed. The experimentally observed pKa was 9.06 which yielded a thermodynamic pKa estimate of 9.38. These results agreed well with one of two conflicting reports in the literature.

Research paper thumbnail of Diffusion and concentration profiles of drugs in gels

Journal of Pharmaceutical Sciences, 1993

Research paper thumbnail of A semiempirical computational investigation of the antipsoriatic drug anthralin

Journal of Pharmaceutical Sciences, 1992

Research paper thumbnail of Effect of SDS Micelles on Rhodamine-B Diffusion in Hydrogels

Journal of Chemical Education, 1996

Research paper thumbnail of Dissolution Controlled Drug Release from Agarose Beads

Drug Development and Industrial Pharmacy, 1994

ABSTRACT Abstract A simple method was used for loading ibuprofen or indomethacin into agarose bea... more ABSTRACT Abstract A simple method was used for loading ibuprofen or indomethacin into agarose beads to obtain sustained release. Placebo beads were prepared by a dropwise addition of a hot aqueous agarose solution into a beaker of chilled mineral oil and water. Prior to loading, the aqueous component in the beads was replaced by repeated soakings in ethanol. Loading was accomplished at room temperature using ethanolic drug solutions. Upon drying, the beads shrank to about a third of their original size. The surface morphology of dried placebo and loaded beads was studied using electron microscopy. The release time at 37° C and pH 7.5 increased with drug loading and at 50% loading the release time was 4 hours for indomethacin and 6 hours for ibuprofen. Release of chlorpheniramine from dried and swollen beads was examined to elucidate the release mechanism. From dissolution studies it was concluded that the delay due to swelling is less than 10 minutes, chlorpheniramine release from swollen beads was primarily diffusion controlled, and the release mechanism for indomethacin and ibuprofen has three components: i) swelling of the beads, ii) dissolution of crystallized drug, and iii) diffusion of dissolved drug from the beads.

Research paper thumbnail of Avicel RC-591/Chitosan Beads by Extrusion-Spheronization Technology

Drug Development and Industrial Pharmacy, 1993

... Gifts of different grades of chitosan by Protan Inc. (Portsmouth, NH) and GD Searle (Skokie, ... more ... Gifts of different grades of chitosan by Protan Inc. (Portsmouth, NH) and GD Searle (Skokie, IL) are also appreciated. REFERENCES 1. 2. 3. 4. ... CW Woodruff and N. 0. Nuessle, J. Pharm. Sci., 61, 787 (1972). IM Jalal, HJ Malinowski and WE Smith, J. Pharm. Sci., a, 1466 (1972). ...

Research paper thumbnail of Direct Compression Controlled Release Tablets Using Ethylcellulose Matrices

Drug Development and Industrial Pharmacy, 1993

... SUE., 10, 323 (1973). 8. NA Shaikh, SE Abidi and LH Block, Drug Dev. Ind. Pharm., 13, 1345 (1... more ... SUE., 10, 323 (1973). 8. NA Shaikh, SE Abidi and LH Block, Drug Dev. Ind. Pharm., 13, 1345 (1987). 9. NA Shaikh, SE Abidi and LH Block, Drug Dev. Ind. Pharm., 13, 2495 (1987). 10. S. I. Pather, Personal communication, 1990. 11. ...

Research paper thumbnail of A Factorial Approach to High Dose Product Development by an Extrusion/Spheronization Process

Drug Development and Industrial Pharmacy, 1993

AbstractExtrusion/spheronization technology has been used for preparing high drug-loaded pellets.... more AbstractExtrusion/spheronization technology has been used for preparing high drug-loaded pellets. Typical formulations include 40-60% microcrystalline cellulose (MCC) to impart the plastic characteristics required for this process. Studies have suggested that pellets containing greater than 80% drug are difficult to process and require special grades of MCC. Most of these studies focused on either the process or formulation aspects of the product and failed to explore the interactions of process and product. Statistical experimental designs are well suited for exploring both process and product variables and their interactions with each other. This study addresses pelletization of a high dose drug with low density. A Nica® radial (basket-type) extruder was used in extrudate preparation, followed by spheronization on a serrated plate spheronizer. A Plackett-Burman screening design was employed to investigate product and process parameters affecting final pellet drug content, density and roundness. MCC type...

Research paper thumbnail of Chitosan as a tablet binder

Drug Development and Industrial Pharmacy, 1992

AbstractChitosan was evaluated as a binder for chlorpheniramine maleate tablets in comparison wit... more AbstractChitosan was evaluated as a binder for chlorpheniramine maleate tablets in comparison with other cellulose binders such as sodium carboxymethylcellulose, hydroxypropylmethylcellulose and methylcellulose. The effects of binder concentration on the mechanical properties of granules and tablets as well as on disintegration time and dissolution profiles were studied. Results showed that granules prepared with methylcellulose had lowest percentage of fines and friability. Chitosan tablets showed best dissolution profiles. The rank order correlation for binder efficiency was: hydroxypropylmethylcellulose > chitosan > methylcellulose > sodium carboxymethylcellulose.

Research paper thumbnail of Decomposition of Anthralin in Alkaline Solutions

Drug Development and Industrial Pharmacy, 1988

... DECOMPOSITION OF ANTHRALIN IN ALKALINE SOLUTIONS Sathyanarayana M. Upadrashta and Dale Eric W... more ... DECOMPOSITION OF ANTHRALIN IN ALKALINE SOLUTIONS Sathyanarayana M. Upadrashta and Dale Eric Wurster'i College of Pharmacy, The University of Iowa, Iowa City, IA 52242 ABSTRACT ... The CHEMET tube contained an indigo-carmine color forming reagent in acid ...

Research paper thumbnail of Oestrone loaded poly(l-lactic acid) microspheres: preparation, evaluation and in vitro release kinetics

Journal of Microencapsulation, 1993

Poly(l-lactic acid) microspheres containing oestrone were prepared by the solvent evaporation met... more Poly(l-lactic acid) microspheres containing oestrone were prepared by the solvent evaporation method using methylene chloride as the casting solvent and poly(vinyl alcohol) as the emulsifier. Non-agglomerated microspheres with average diameters of 125-160 microns, containing 3-18 per cent oestrone were prepared successfully using a stirring rate of 650 rpm and a poly(vinyl alcohol) concentration as low as 0.15%. Drug loading decreased with an increase in the relative amounts of methylene chloride or emulsifier. Microspheres with 9 per cent loading released approximately 50 per cent of the drug in the first 12 h and the remainder at a much slower rate over several days. Initial examination revealed that the kinetic data followed both a first-order release pattern and the Higuchi matrix model. Differential rate treatment confirmed the Higuchi matrix model and the release mechanism was determined to be diffusion-controlled.

Research paper thumbnail of Development of Matrix Controlled Release Beads by Extrusion-Spheronization Technology Using a Statistical Screening Design

Drug Development and Industrial Pharmacy, 1994

... Sanjay R. Goskondal, Gregory A. Hileman1*2, and Sathyanarayana M. Upadrashtal~~, 1School of P... more ... Sanjay R. Goskondal, Gregory A. Hileman1*2, and Sathyanarayana M. Upadrashtal~~, 1School of Pharmacy, University of Missouri-Kansas City, Kansas City ... Several materials failed in retarding drug release 8. Carnuba wax was an exception, again at low drug concentrations. ...

Research paper thumbnail of Drug Solubility Effects on Predicting Optimum Conditions for Extrusion and Spheronization of Pellets

Pharmaceutical Development and Technology, 1997

This paper explores the utility of aqueous solubility of structurally similar drugs in predicting... more This paper explores the utility of aqueous solubility of structurally similar drugs in predicting optimum conditions for extrusion and spheronization of pellets using response surface methodology. Pharmacologically active xanthine derivatives exhibiting widely varying aqueous solubility were used to determine optimum conditions for pelletization. The amount of water added to the formulation, wet mixing time, and spheronizing time were explored in a series of central composite experimental designs to exhaustively explore and mathematically model the response surfaces for each drug. Using a marketed microcrystalline cellulose excipient, optimum extrusion and spheronization conditions for less soluble drugs required more water, a longer wet mixing time, and prolonged spheronizing times. Results were similar when a new microcrystalline cellulose was substituted, except that more water was required. When comparing results for different drugs, a strong linear relationship was observed between the aqueous solubility of the drug and the water content required for optimum pellet production. The water content range over which quality pellets could be produced was much broader for poorly soluble drugs. Aqueous solubility of the active component appears to be a good predictor for the water requirements for optimum extrusion and spheronization of pellets for pharmaceutical applications.

Research paper thumbnail of Response surface optimization of high dose pellets by extrusion and spheronization

International Journal of Pharmaceutics, 1993

... 03281 Response surface optimization of high dose pellets by extrusion and spheronization Greg... more ... 03281 Response surface optimization of high dose pellets by extrusion and spheronization Gregory A. Hileman '''b, Sanjay R. Goskonda a, Anthony J. Spalitto b and Sathyanarayana M. Upadrashta ... Pellets with roundness scores less than 1.20 ap-pear increasingly more smooth ...

Research paper thumbnail of Equilibrium binding studies of the interaction between anthralin and bovine serum albumin

International Journal of Pharmaceutics, 1989

Abstract The binding of the antipsoriatic drug, anthralin, to calf thymus deoxyribonucleic acid (... more Abstract The binding of the antipsoriatic drug, anthralin, to calf thymus deoxyribonucleic acid (DNA) and bovine serum albumin (BSA) was examined using fluorescence spectroscopy. Results indicated that anthralin did not bind to DNA but did bind to BSA at physiological pH. Job's method of continuous variation indicated that anthralin formed a 1:1 complex with BSA. The investigation employing BSA was conducted at 4 different temperatures, 8.0, 15.4, 25.0 and 34.7°C. Langmuir's one-site model was directly fitted to the data with an iterative non-linear regression program. The thermodynamic parameters derived from the van't Hoff plot were as follows: ΔG = −8.19 kcal/mol, ΔH = −7.85 kcal/mol, and ΔS = +1.12 e.u. On the basis of experimental evidence it is pr that anthralin binds to a tryptophan residue on BSA by a hydrogen bonding mechanism.

Research paper thumbnail of Equilibrium binding studies of the 1,8-dihydroxy-9,10-anthraquinone-bovine serum albumin interaction

International Journal of Pharmaceutics, 1989

The binding of 1,8~ihydroxy-9,10-anthraquinone (DAQ) to bovine serum albumin (BSA) was investigat... more The binding of 1,8~ihydroxy-9,10-anthraquinone (DAQ) to bovine serum albumin (BSA) was investigated using fluorescence spectroscopy. The fluorescence of BSA was quenched following interaction with DAQ and this property was used to generate binding isotherms. Binding studies were conducted at 5 different temperatures: 8.0, 15.4, 25.0, 29.7 and 34.7 o C. The thermodynamic parameters at 2S" C derived from the van't Hoff plot were as follows: AG =-8.03 kcal/mol, AH =-11.8 kcal/mol, and AS =-12.6 e.u. Based on these results it is postulated that DAQ binds to a tryptophan residue on albumin mainly by hydrogen bonding. A statistical technique employing joint confidence ellipsoids has shown that the parameter vectors for anthralin and DAQ are different at the 90% confidence level thus indicating differences in binding affinities. Competitive binding experiments were also conducted and the results indicated that DAQ competitively inhibits the albumin binding of anthralin. In~~uction Recently it has been shown (Upadrashta and Wurster, 1989) that anthrahn, an antipsoriatic agent, binds to bovine serum albumin (BSA). This drug-protein interaction exhibits a 1 : 1 stoichiometry and a binding constant of 1.01 X lo6 M-' (Upadrashta and Wurster, 1989). AnthraIin rapidly decomposes in aqueous solutions (Upadrashta and Wurster, 1988a, Melo et al., 1983) near neutral pH

Research paper thumbnail of Controlled release pellets by extrusion-spheronization

International Journal of Pharmaceutics, 1994

Research paper thumbnail of Ethylcellulose matrix controlled release tablets of a water-soluble drug

International Journal of Pharmaceutics, 1995

Research paper thumbnail of Compressibility and compactibility properties of ethylcellulose

International Journal of Pharmaceutics, 1994

Compaction characteristics of various viscosity grades of ethylcellulose were examined using an i... more Compaction characteristics of various viscosity grades of ethylcellulose were examined using an instrumented tablet press. Four different data analysis techniques were employed to characterize the compactibility and compressibility data: tablet hardness-compression force profiles, ejected tablet Heckei analysis, work calculations from force-displacement data and force-time profile analysis. The calculated parameters derived from these approaches included the following: mean yield pressure from the Heckel analysis, net work and elastic work from the force-displacement data and the area to height (A/H) ratio from force-time data. Lower viscosity grades of ethylcellulose were found to be more compactible as described by tablet hardness-compression force profiles. Lower viscosity grades also exhibited a lower mean yield pressure from the Heckel analysis, indicating greater compressibility. Higher viscosity grades exhibited a decrease in net work and an increase in elastic work. Higher viscosity grades also exhibited greater values for the A/H ratio derived from force-time analysis, indicating lower compressibility. Higher viscosity grades of ethylcellulose showed increases in true density, melting point, and heat of fusion. The variation in compactibility and compressibility properties of different viscosity grades of ethylcellulose can be attributed to changes in the polymer's degree of order.

Research paper thumbnail of Consolidation of ethylcellulose: Effect of particle size, press speed, and lubricants

International Journal of Pharmaceutics, 1995

ABSTRACT

Research paper thumbnail of Spectroscopic Analysis of the Ionization Behavior of Anthralin

Spectroscopy Letters, 1988

Abstract The ionic equilibria of anthralin were examined at 25°C in aqueous solutions varying in ... more Abstract The ionic equilibria of anthralin were examined at 25°C in aqueous solutions varying in pH from 5.10 to 11.74. Despite the presence of three phenol groups, only one pKa was observed under a these experimental conditions and even at pH - 11.74 there was no spectroscopic evidence for the presumed second pKa Possible a causes for this result are discussed. The experimentally observed pKa was 9.06 which yielded a thermodynamic pKa estimate of 9.38. These results agreed well with one of two conflicting reports in the literature.

Research paper thumbnail of Diffusion and concentration profiles of drugs in gels

Journal of Pharmaceutical Sciences, 1993

Research paper thumbnail of A semiempirical computational investigation of the antipsoriatic drug anthralin

Journal of Pharmaceutical Sciences, 1992

Research paper thumbnail of Effect of SDS Micelles on Rhodamine-B Diffusion in Hydrogels

Journal of Chemical Education, 1996

Research paper thumbnail of Dissolution Controlled Drug Release from Agarose Beads

Drug Development and Industrial Pharmacy, 1994

ABSTRACT Abstract A simple method was used for loading ibuprofen or indomethacin into agarose bea... more ABSTRACT Abstract A simple method was used for loading ibuprofen or indomethacin into agarose beads to obtain sustained release. Placebo beads were prepared by a dropwise addition of a hot aqueous agarose solution into a beaker of chilled mineral oil and water. Prior to loading, the aqueous component in the beads was replaced by repeated soakings in ethanol. Loading was accomplished at room temperature using ethanolic drug solutions. Upon drying, the beads shrank to about a third of their original size. The surface morphology of dried placebo and loaded beads was studied using electron microscopy. The release time at 37° C and pH 7.5 increased with drug loading and at 50% loading the release time was 4 hours for indomethacin and 6 hours for ibuprofen. Release of chlorpheniramine from dried and swollen beads was examined to elucidate the release mechanism. From dissolution studies it was concluded that the delay due to swelling is less than 10 minutes, chlorpheniramine release from swollen beads was primarily diffusion controlled, and the release mechanism for indomethacin and ibuprofen has three components: i) swelling of the beads, ii) dissolution of crystallized drug, and iii) diffusion of dissolved drug from the beads.

Research paper thumbnail of Avicel RC-591/Chitosan Beads by Extrusion-Spheronization Technology

Drug Development and Industrial Pharmacy, 1993

... Gifts of different grades of chitosan by Protan Inc. (Portsmouth, NH) and GD Searle (Skokie, ... more ... Gifts of different grades of chitosan by Protan Inc. (Portsmouth, NH) and GD Searle (Skokie, IL) are also appreciated. REFERENCES 1. 2. 3. 4. ... CW Woodruff and N. 0. Nuessle, J. Pharm. Sci., 61, 787 (1972). IM Jalal, HJ Malinowski and WE Smith, J. Pharm. Sci., a, 1466 (1972). ...

Research paper thumbnail of Direct Compression Controlled Release Tablets Using Ethylcellulose Matrices

Drug Development and Industrial Pharmacy, 1993

... SUE., 10, 323 (1973). 8. NA Shaikh, SE Abidi and LH Block, Drug Dev. Ind. Pharm., 13, 1345 (1... more ... SUE., 10, 323 (1973). 8. NA Shaikh, SE Abidi and LH Block, Drug Dev. Ind. Pharm., 13, 1345 (1987). 9. NA Shaikh, SE Abidi and LH Block, Drug Dev. Ind. Pharm., 13, 2495 (1987). 10. S. I. Pather, Personal communication, 1990. 11. ...

Research paper thumbnail of A Factorial Approach to High Dose Product Development by an Extrusion/Spheronization Process

Drug Development and Industrial Pharmacy, 1993

AbstractExtrusion/spheronization technology has been used for preparing high drug-loaded pellets.... more AbstractExtrusion/spheronization technology has been used for preparing high drug-loaded pellets. Typical formulations include 40-60% microcrystalline cellulose (MCC) to impart the plastic characteristics required for this process. Studies have suggested that pellets containing greater than 80% drug are difficult to process and require special grades of MCC. Most of these studies focused on either the process or formulation aspects of the product and failed to explore the interactions of process and product. Statistical experimental designs are well suited for exploring both process and product variables and their interactions with each other. This study addresses pelletization of a high dose drug with low density. A Nica® radial (basket-type) extruder was used in extrudate preparation, followed by spheronization on a serrated plate spheronizer. A Plackett-Burman screening design was employed to investigate product and process parameters affecting final pellet drug content, density and roundness. MCC type...

Research paper thumbnail of Chitosan as a tablet binder

Drug Development and Industrial Pharmacy, 1992

AbstractChitosan was evaluated as a binder for chlorpheniramine maleate tablets in comparison wit... more AbstractChitosan was evaluated as a binder for chlorpheniramine maleate tablets in comparison with other cellulose binders such as sodium carboxymethylcellulose, hydroxypropylmethylcellulose and methylcellulose. The effects of binder concentration on the mechanical properties of granules and tablets as well as on disintegration time and dissolution profiles were studied. Results showed that granules prepared with methylcellulose had lowest percentage of fines and friability. Chitosan tablets showed best dissolution profiles. The rank order correlation for binder efficiency was: hydroxypropylmethylcellulose > chitosan > methylcellulose > sodium carboxymethylcellulose.

Research paper thumbnail of Decomposition of Anthralin in Alkaline Solutions

Drug Development and Industrial Pharmacy, 1988

... DECOMPOSITION OF ANTHRALIN IN ALKALINE SOLUTIONS Sathyanarayana M. Upadrashta and Dale Eric W... more ... DECOMPOSITION OF ANTHRALIN IN ALKALINE SOLUTIONS Sathyanarayana M. Upadrashta and Dale Eric Wurster'i College of Pharmacy, The University of Iowa, Iowa City, IA 52242 ABSTRACT ... The CHEMET tube contained an indigo-carmine color forming reagent in acid ...