Gul Majid Khan | Quaid-i-Azam University, Islamabad, Pakistan (original) (raw)

Papers by Gul Majid Khan

Research paper thumbnail of Formulation and evaluation of controlled release matrices of ketoprofen and influence of different co-excipients on the release mechanism

Research paper thumbnail of Dengue fever again in Pakistan: are we going in the right direction?

Public health, Jan 8, 2017

Research paper thumbnail of Controlled Release Coprecipitates of Ibuprofen and Carbopol® 934p-NF: Preparation, Characterization and in Vitro Drug Release

Journal of Medical Sciences(Faisalabad), 2001

Research paper thumbnail of Pathology of the Appendix

Journal of Clinical Pathology, 1994

Typical slender, tapering Gram negative bacilli have been reported in buffy coat preparations of ... more Typical slender, tapering Gram negative bacilli have been reported in buffy coat preparations of 12 of 13 such cases in which staining was attempted.2 In two cases of overwhelming C canimorsus septicaemia whole blood smears were reported positive.34 A further case, in a 36 year old man without a spleen, presented 36 hours after a trivial dog bite, with purpura fulminans and disseminated intracellular coagulation. The history of dog bite, asplenia, and Gram negative intracellular rods present in the whole blood smear immediately suggested the diagnosis and led to a change from the initial empirical antimicrobial treatment for Gram negative septicaemia with a successful outcome. Gram negative septicaemias generally respond to aminoglycoside treatment, but C canimorsus infections do not. The antimicrobial agents of choice for such infections are penicillin or ciprofloxacin.

Research paper thumbnail of Comparative Study of various Growth Media in Isolation of Urinary Tract Pathogens

Background: Background: Background: Background: Background: Since a wide spectrum of bacteria are... more Background: Background: Background: Background: Background: Since a wide spectrum of bacteria are responsible for causing urinary tract infections. To cover the maximum yield of isolates a study was designed in which a combination of media was used for detection of both gram positive and gram-negative bacteria.

Research paper thumbnail of GM Khan CV & List of Publications

Research paper thumbnail of Thiomers and their potential applications in drug delivery

Abstract: Introduction: Thiomers are the product of the immobilization of sulfhydryl-bearing lig... more Abstract:
Introduction: Thiomers are the product of the immobilization of sulfhydryl-bearing ligands onto the polymer backbone of a conventional polymer, which results in a significant improvement in mucoadhesion; in situ gelation and efflux inhibition compare with unchanged polymers. Because of thiol groups, thiomers have more reactivity and enhanced protection against oxidation. Since the late 1990s, extensive work has been conducted on these promising polymeric excipients in the pharmaceutical field.
Areas Covered: This review covers thiomers, their classification and their different properties. Various techniques for the synthesis, purification and characterization of thiomers are described in detail. This review also encompasses their various properties such as mucoadhesion, permeation enhancement, in situ gelation and efflux inhibition, as well as different formulations based on thiomers. In addition to the use of thiomers as multifunctional excipients, this review also encompasses their use as drugs.
Expert Opinion: The synthesis is realized by linkage of sulfhydryl-bearing ligands but reported methods give low yields. Higher degrees of modification are not necessary and would probably lead to extreme changes in properties. Nevertheless, an accurate characterization of the final product is important. The scale-up procedure for industrial manufacturing has been adapted to produce GMP materials; Lacrimera® eye drops have already entered the European market.

Research paper thumbnail of 2017-CV & List of Publications.docx

Research paper thumbnail of Preparation and Evaluation of Controlled Release Tablets Containing Ciprofloxacin HCl: Influence of Polymer Concentrations on In Vitro Drug Release Profiles

The aim of the presented study was to formulate and evaluate ciprofloxacin controlled release mat... more The aim of the presented study was to formulate and evaluate ciprofloxacin controlled release matrix tablets using different concentrations of polymer Eudragit in order to see their effect on drug release profiles during in vitro dissolution studies. Ciprofloxacin controlled release tablets were prepared with Eudragit by direct compression method. Several ratios of drug to polymer were used to develop optimized CR formulations having nearly constant blood plasma concentrations and to investigate the affect of polymer concentration on drug release rates during in vitro dissolution studies. The developed tablets were physically evaluated using different parameters including physical appearance, hardness, drug content, friability and dimensional tests. The in vitro drug dissolution studies were performed in phosphate buffer pH 7.4 using USP method-I (rotating basket method) with the help of Pharma Test dissolution apparatus and maintaining the temperature at 37 °C ± 0.1. The drug transport mechanism from tablets was elucidated by using various mathematical/kinetic models employed to dissolution data. Similarity factor f 2 was employed to the release profiles of formulations from the test and a reference conventional formulation to check the similarities and differences between the release profiles. Accelerated stability studies were performed on the optimized tablets under accelerated storage conditions of 40 ± 2 °C and 75 ± 5 % relative humidity for a period of 6 months.

Research paper thumbnail of Antifungal Activities of Tamarix Dioica-An In Vitro Study

Research paper thumbnail of Formulation and evaluation of directly compressed Ofloxacin-Ethocel controlled release tablets: A kinetic approach

In this study, Controlled release matrix tablets of Ofloxacin-Ethocel at different drug to polyme... more In this study, Controlled release matrix tablets of Ofloxacin-Ethocel at different drug to polymer ratios were prepared by direct compression method. Main focus of this investigative study was the release patterns and release rates of drug from the matrix tablets, the influence of several co-excipients (CMC, HPMC and Starch) on the drug release rates and the mechanism involved. Different grades of Ethocel were used in this study including (7P, 7FP, 10P, 10FP, 100P and 100FP). In vitro dissolution studies in phosphate buffer PH 7.4 showed the prolonged release of drug from the formulations containing Ethocel Premium and FP polymers, but most prominently prolonged release was from the formulations containing FP Premium polymers of Ethocel. All the co-excipients used in Ofloxacin-Ethocel CR tablets enhanced the release rate of Ofloxacin from the matrix tablets but the most rapid release of drug from the tablets was found in the formulations having CMC as co-excipient. The co-excipients enhanced the release rate in the order of CMC > HPMC > Starch. Dissimilarity factor f 1 and similarity factor f 2 were applied to the formulations for the checking of dissimilarities and similarities between the release profiles of drug from the test and the reference standard formulation.

Research paper thumbnail of The influence of different plasticizers on some physical and mechanical properties of hydroxypropyl methylcellulose free films

Pakistan journal of pharmaceutical sciences, 2005

Coating has been widely used in pharmaceutical manufacture either as non-functional or a function... more Coating has been widely used in pharmaceutical manufacture either as non-functional or a functional entity. The objectives of the present study were to investigate the effect of plasticizers such as PEG400, PEG1000 and triacetin on mechanical properties, glass transition temperature and water vapor transmission of free films prepared from HPMC and/or HPMC:PVA blends, to develop suitable coating system for tablets, and to determine the release profiles of the coated tablets. The tensile strength of plasticized HPMC films was generally lower than that of control HPMC film and could be attributed to increased crystallinity and segmental chain mobility of HPMC. This effect increased as the concentration of plasticizer increased. Generally the addition of both grades of polyethylene glycol (PEG400 & PEG1000) increased the moisture permeability of HPMC films but the films containing triacetin provided a more rigid barrier to moisture compared to unplasticized HPMC films. The dissolution p...

Research paper thumbnail of Effect of Tetrakis-µ-3,5-di-isopropylsalicylatodiaquodicopper (II) and Sodium Gold (I) Thiomalate (Myocrisin) on the Metabolism of Plasma Thiol in the Rheumatoid Arthritis Patients and Volunteer Human Blood

Journal of Medical Sciences(Faisalabad), 2001

ABSTRACT The effects of tetrakis-?-3,5-di-isopropyl Salicylatodiaquodicopper (II) (3,5-DIPS)4 (H2... more ABSTRACT The effects of tetrakis-?-3,5-di-isopropyl Salicylatodiaquodicopper (II) (3,5-DIPS)4 (H2O)2 and sodium gold (I) thiomalate (Myocrisin) Au(I) (S-CHCH2(CO2)2Na2 on the metabolism of plasma thiol in volunteer human blood and/or rheumatoid arthritis (RA) patients phase-I were compared and examined. Human blood and/or plasma was incubated with Cu (II) (3,5-DIPS)4 (H2O)2. Plasma thiol was measured by spectrophotometer using Ellman`s reagent for derivatization. Myocrisin was administered to RA patients in phase-I and blood was collected for plasma thiol determination using Ellman`s method. Both copper and gold complexes and/or drugs increased the concentrations of plasma thiol as compared to control group and/or in RA patients. Both copper and gold were found to have the potential to enhance the release of thiol from plasma by affecting the exposure of hidden thiol, contained in plasma proteins and enzymes. These results suggested that these complexes and/or drugs perhaps caused the leakage of the hidden plasma thiols present in proteins and enzymes preferably on albumin, a major thiol containing protein in plasma. This alteration in plasma thiol concentration in blood and/or plasma by copper and gold complex and/or drug may count towards their some pharmacological effects.

Research paper thumbnail of Improved Microbial Production of Lysine by Developing a New Auxotrophic Mutant of Corneybacterium glutamicum

Pakistan Journal of Biological Sciences, 2002

Research paper thumbnail of Synthesis and characterization of some novel triphenylarsenic(V) derivatives of monofunctional bidentate 2,2-disubstituted benzothiazoline ligands

Heteroatom Chemistry, 2007

Research paper thumbnail of Preparation, characterization and dissolution behavior of artemisinin microparticles

Advanced Powder Technology, 2011

In the present study, a modified 4-fluid nozzle spray drier was used to prepare microparticles of... more In the present study, a modified 4-fluid nozzle spray drier was used to prepare microparticles of a poorly water soluble drug, artemisinin with the aim of improving its solubility. We also investigated the effect of process variables on the physical properties and dissolution rate of spray dried artemisinin. A full factorial experimentally designed study was performed to investigate the following

Research paper thumbnail of Impact of Ethyl Cellulose Ether Derivative (Ethocel) on the In Vitro and In Vivo Release of Nimesulide from Matrix Tablets

Research paper thumbnail of Formulation and Evaluation of Tramadol HCl Matrix Tablets Using Carbopol 974P and 934 as Rate-Controlling Agents

To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 97... more To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 974P and 934 polymers as rate-controlling agents. Methods: The tablets were prepared by direct compression method using various drug to polymer (D:P) ratios. Co-excipients, including carboxymethylcellulose, starch and/or hydroxypropyl methylcellulose were also used to modulate the formulations. Various physical tests and in vitro dissolution studies were carried out on the formulations. The dissolution data were subjected to various release models Results: As the concentration of the polymer (rate-controlling agent) increased, dissolution rate decreased, For the formulation containing Carbopol 974P at D:P ratio of 10:7, drug release decreased to 83 % compared with the release rate of 99 % for the formulation with D:P ratio of 10:3. Kinetic analysis indicates that drug release mechanism was anomalous non-Fickian diffusion. Conclusion: Both Carbopol 974P and 934 can be used as rate-controlling agents in the formulation of tramadol HCl CR tablets. Appropriate selection of drug/polymer ratio can be applied effectively to modulate the dissolution rate of the drug.

Research paper thumbnail of Formulation and Evaluation of Tramadol HCl Matrix Tablets Using Carbopol 974P and 934 as Rate-Controlling Agents

To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 97... more To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 974P and 934 polymers as rate-controlling agents. Methods: The tablets were prepared by direct compression method using various drug to polymer (D:P) ratios. Co-excipients, including carboxymethylcellulose, starch and/or hydroxypropyl methylcellulose were also used to modulate the formulations. Various physical tests and in vitro dissolution studies were carried out on the formulations. The dissolution data were subjected to various release models Results: As the concentration of the polymer (rate-controlling agent) increased, dissolution rate decreased, For the formulation containing Carbopol 974P at D:P ratio of 10:7, drug release decreased to 83 % compared with the release rate of 99 % for the formulation with D:P ratio of 10:3. Kinetic analysis indicates that drug release mechanism was anomalous non-Fickian diffusion. Conclusion: Both Carbopol 974P and 934 can be used as rate-controlling agents in the formulation of tramadol HCl CR tablets. Appropriate selection of drug/polymer ratio can be applied effectively to modulate the dissolution rate of the drug.

Research paper thumbnail of Controlled Release Drug Delivery Systems Containing Diltiazem HCl: Effect of Polymer Concentration on In Vitro Drug Release Profiles

In this study, controlled release matrix tablets of diltiazem HCl were prepared by direct compres... more In this study, controlled release matrix tablets of diltiazem HCl were prepared by direct compression method using Ethocel as rate controlling polymer. The CR tablets of diltiazem HCl were formulated at different drug to polymer ratios to see the effect of polymer concentration on the release of drug during in vitro drug dissolution studies. Different physico-chemical tests were performed on matrix tablets to evaluate their suitability for in vitro and in vivo drug release performance. In vitro dissolution studies were performed in phosphate buffer pH 7.4 with PharmaTest Dissolution Apparatus, using USP method-I (rotating basket method) at a rotation speed of 100 rpm by maintaining the temperature constant at 37 ± 0.1 °C. Several kinetic models were used for evaluating the dissolution data to find out the drug transport mechanism from the polymeric tablets into dissolution medium which were found to be occurred both by swelling controlled mechanism as well as diffusion mechanism, exhibiting nearly zero order kinetics. In vivo evaluation of diltiazem HCl CR tablets was determined in rabbit serum according to randomized twoway crossover study design. Several pharmacokinetic parameters including plasma concentration time curve (AUC 0-∞ ), maximum plasma concentration (C max ), time to reach peak plasma concentration (T max ), elimination half life (T 1/2 ), and apparent volume of distribution (Vd/f) were estimated from the plasma concentration-time profile of individual rabbit. An optimized C max and extended T max were produced and a good correlation of in vivo and in vitro drug absorption (R 2 = 0.952) was observed.

Research paper thumbnail of Formulation and evaluation of controlled release matrices of ketoprofen and influence of different co-excipients on the release mechanism

Research paper thumbnail of Dengue fever again in Pakistan: are we going in the right direction?

Public health, Jan 8, 2017

Research paper thumbnail of Controlled Release Coprecipitates of Ibuprofen and Carbopol® 934p-NF: Preparation, Characterization and in Vitro Drug Release

Journal of Medical Sciences(Faisalabad), 2001

Research paper thumbnail of Pathology of the Appendix

Journal of Clinical Pathology, 1994

Typical slender, tapering Gram negative bacilli have been reported in buffy coat preparations of ... more Typical slender, tapering Gram negative bacilli have been reported in buffy coat preparations of 12 of 13 such cases in which staining was attempted.2 In two cases of overwhelming C canimorsus septicaemia whole blood smears were reported positive.34 A further case, in a 36 year old man without a spleen, presented 36 hours after a trivial dog bite, with purpura fulminans and disseminated intracellular coagulation. The history of dog bite, asplenia, and Gram negative intracellular rods present in the whole blood smear immediately suggested the diagnosis and led to a change from the initial empirical antimicrobial treatment for Gram negative septicaemia with a successful outcome. Gram negative septicaemias generally respond to aminoglycoside treatment, but C canimorsus infections do not. The antimicrobial agents of choice for such infections are penicillin or ciprofloxacin.

Research paper thumbnail of Comparative Study of various Growth Media in Isolation of Urinary Tract Pathogens

Background: Background: Background: Background: Background: Since a wide spectrum of bacteria are... more Background: Background: Background: Background: Background: Since a wide spectrum of bacteria are responsible for causing urinary tract infections. To cover the maximum yield of isolates a study was designed in which a combination of media was used for detection of both gram positive and gram-negative bacteria.

Research paper thumbnail of GM Khan CV & List of Publications

Research paper thumbnail of Thiomers and their potential applications in drug delivery

Abstract: Introduction: Thiomers are the product of the immobilization of sulfhydryl-bearing lig... more Abstract:
Introduction: Thiomers are the product of the immobilization of sulfhydryl-bearing ligands onto the polymer backbone of a conventional polymer, which results in a significant improvement in mucoadhesion; in situ gelation and efflux inhibition compare with unchanged polymers. Because of thiol groups, thiomers have more reactivity and enhanced protection against oxidation. Since the late 1990s, extensive work has been conducted on these promising polymeric excipients in the pharmaceutical field.
Areas Covered: This review covers thiomers, their classification and their different properties. Various techniques for the synthesis, purification and characterization of thiomers are described in detail. This review also encompasses their various properties such as mucoadhesion, permeation enhancement, in situ gelation and efflux inhibition, as well as different formulations based on thiomers. In addition to the use of thiomers as multifunctional excipients, this review also encompasses their use as drugs.
Expert Opinion: The synthesis is realized by linkage of sulfhydryl-bearing ligands but reported methods give low yields. Higher degrees of modification are not necessary and would probably lead to extreme changes in properties. Nevertheless, an accurate characterization of the final product is important. The scale-up procedure for industrial manufacturing has been adapted to produce GMP materials; Lacrimera® eye drops have already entered the European market.

Research paper thumbnail of 2017-CV & List of Publications.docx

Research paper thumbnail of Preparation and Evaluation of Controlled Release Tablets Containing Ciprofloxacin HCl: Influence of Polymer Concentrations on In Vitro Drug Release Profiles

The aim of the presented study was to formulate and evaluate ciprofloxacin controlled release mat... more The aim of the presented study was to formulate and evaluate ciprofloxacin controlled release matrix tablets using different concentrations of polymer Eudragit in order to see their effect on drug release profiles during in vitro dissolution studies. Ciprofloxacin controlled release tablets were prepared with Eudragit by direct compression method. Several ratios of drug to polymer were used to develop optimized CR formulations having nearly constant blood plasma concentrations and to investigate the affect of polymer concentration on drug release rates during in vitro dissolution studies. The developed tablets were physically evaluated using different parameters including physical appearance, hardness, drug content, friability and dimensional tests. The in vitro drug dissolution studies were performed in phosphate buffer pH 7.4 using USP method-I (rotating basket method) with the help of Pharma Test dissolution apparatus and maintaining the temperature at 37 °C ± 0.1. The drug transport mechanism from tablets was elucidated by using various mathematical/kinetic models employed to dissolution data. Similarity factor f 2 was employed to the release profiles of formulations from the test and a reference conventional formulation to check the similarities and differences between the release profiles. Accelerated stability studies were performed on the optimized tablets under accelerated storage conditions of 40 ± 2 °C and 75 ± 5 % relative humidity for a period of 6 months.

Research paper thumbnail of Antifungal Activities of Tamarix Dioica-An In Vitro Study

Research paper thumbnail of Formulation and evaluation of directly compressed Ofloxacin-Ethocel controlled release tablets: A kinetic approach

In this study, Controlled release matrix tablets of Ofloxacin-Ethocel at different drug to polyme... more In this study, Controlled release matrix tablets of Ofloxacin-Ethocel at different drug to polymer ratios were prepared by direct compression method. Main focus of this investigative study was the release patterns and release rates of drug from the matrix tablets, the influence of several co-excipients (CMC, HPMC and Starch) on the drug release rates and the mechanism involved. Different grades of Ethocel were used in this study including (7P, 7FP, 10P, 10FP, 100P and 100FP). In vitro dissolution studies in phosphate buffer PH 7.4 showed the prolonged release of drug from the formulations containing Ethocel Premium and FP polymers, but most prominently prolonged release was from the formulations containing FP Premium polymers of Ethocel. All the co-excipients used in Ofloxacin-Ethocel CR tablets enhanced the release rate of Ofloxacin from the matrix tablets but the most rapid release of drug from the tablets was found in the formulations having CMC as co-excipient. The co-excipients enhanced the release rate in the order of CMC > HPMC > Starch. Dissimilarity factor f 1 and similarity factor f 2 were applied to the formulations for the checking of dissimilarities and similarities between the release profiles of drug from the test and the reference standard formulation.

Research paper thumbnail of The influence of different plasticizers on some physical and mechanical properties of hydroxypropyl methylcellulose free films

Pakistan journal of pharmaceutical sciences, 2005

Coating has been widely used in pharmaceutical manufacture either as non-functional or a function... more Coating has been widely used in pharmaceutical manufacture either as non-functional or a functional entity. The objectives of the present study were to investigate the effect of plasticizers such as PEG400, PEG1000 and triacetin on mechanical properties, glass transition temperature and water vapor transmission of free films prepared from HPMC and/or HPMC:PVA blends, to develop suitable coating system for tablets, and to determine the release profiles of the coated tablets. The tensile strength of plasticized HPMC films was generally lower than that of control HPMC film and could be attributed to increased crystallinity and segmental chain mobility of HPMC. This effect increased as the concentration of plasticizer increased. Generally the addition of both grades of polyethylene glycol (PEG400 & PEG1000) increased the moisture permeability of HPMC films but the films containing triacetin provided a more rigid barrier to moisture compared to unplasticized HPMC films. The dissolution p...

Research paper thumbnail of Effect of Tetrakis-µ-3,5-di-isopropylsalicylatodiaquodicopper (II) and Sodium Gold (I) Thiomalate (Myocrisin) on the Metabolism of Plasma Thiol in the Rheumatoid Arthritis Patients and Volunteer Human Blood

Journal of Medical Sciences(Faisalabad), 2001

ABSTRACT The effects of tetrakis-?-3,5-di-isopropyl Salicylatodiaquodicopper (II) (3,5-DIPS)4 (H2... more ABSTRACT The effects of tetrakis-?-3,5-di-isopropyl Salicylatodiaquodicopper (II) (3,5-DIPS)4 (H2O)2 and sodium gold (I) thiomalate (Myocrisin) Au(I) (S-CHCH2(CO2)2Na2 on the metabolism of plasma thiol in volunteer human blood and/or rheumatoid arthritis (RA) patients phase-I were compared and examined. Human blood and/or plasma was incubated with Cu (II) (3,5-DIPS)4 (H2O)2. Plasma thiol was measured by spectrophotometer using Ellman`s reagent for derivatization. Myocrisin was administered to RA patients in phase-I and blood was collected for plasma thiol determination using Ellman`s method. Both copper and gold complexes and/or drugs increased the concentrations of plasma thiol as compared to control group and/or in RA patients. Both copper and gold were found to have the potential to enhance the release of thiol from plasma by affecting the exposure of hidden thiol, contained in plasma proteins and enzymes. These results suggested that these complexes and/or drugs perhaps caused the leakage of the hidden plasma thiols present in proteins and enzymes preferably on albumin, a major thiol containing protein in plasma. This alteration in plasma thiol concentration in blood and/or plasma by copper and gold complex and/or drug may count towards their some pharmacological effects.

Research paper thumbnail of Improved Microbial Production of Lysine by Developing a New Auxotrophic Mutant of Corneybacterium glutamicum

Pakistan Journal of Biological Sciences, 2002

Research paper thumbnail of Synthesis and characterization of some novel triphenylarsenic(V) derivatives of monofunctional bidentate 2,2-disubstituted benzothiazoline ligands

Heteroatom Chemistry, 2007

Research paper thumbnail of Preparation, characterization and dissolution behavior of artemisinin microparticles

Advanced Powder Technology, 2011

In the present study, a modified 4-fluid nozzle spray drier was used to prepare microparticles of... more In the present study, a modified 4-fluid nozzle spray drier was used to prepare microparticles of a poorly water soluble drug, artemisinin with the aim of improving its solubility. We also investigated the effect of process variables on the physical properties and dissolution rate of spray dried artemisinin. A full factorial experimentally designed study was performed to investigate the following

Research paper thumbnail of Impact of Ethyl Cellulose Ether Derivative (Ethocel) on the In Vitro and In Vivo Release of Nimesulide from Matrix Tablets

Research paper thumbnail of Formulation and Evaluation of Tramadol HCl Matrix Tablets Using Carbopol 974P and 934 as Rate-Controlling Agents

To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 97... more To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 974P and 934 polymers as rate-controlling agents. Methods: The tablets were prepared by direct compression method using various drug to polymer (D:P) ratios. Co-excipients, including carboxymethylcellulose, starch and/or hydroxypropyl methylcellulose were also used to modulate the formulations. Various physical tests and in vitro dissolution studies were carried out on the formulations. The dissolution data were subjected to various release models Results: As the concentration of the polymer (rate-controlling agent) increased, dissolution rate decreased, For the formulation containing Carbopol 974P at D:P ratio of 10:7, drug release decreased to 83 % compared with the release rate of 99 % for the formulation with D:P ratio of 10:3. Kinetic analysis indicates that drug release mechanism was anomalous non-Fickian diffusion. Conclusion: Both Carbopol 974P and 934 can be used as rate-controlling agents in the formulation of tramadol HCl CR tablets. Appropriate selection of drug/polymer ratio can be applied effectively to modulate the dissolution rate of the drug.

Research paper thumbnail of Formulation and Evaluation of Tramadol HCl Matrix Tablets Using Carbopol 974P and 934 as Rate-Controlling Agents

To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 97... more To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 974P and 934 polymers as rate-controlling agents. Methods: The tablets were prepared by direct compression method using various drug to polymer (D:P) ratios. Co-excipients, including carboxymethylcellulose, starch and/or hydroxypropyl methylcellulose were also used to modulate the formulations. Various physical tests and in vitro dissolution studies were carried out on the formulations. The dissolution data were subjected to various release models Results: As the concentration of the polymer (rate-controlling agent) increased, dissolution rate decreased, For the formulation containing Carbopol 974P at D:P ratio of 10:7, drug release decreased to 83 % compared with the release rate of 99 % for the formulation with D:P ratio of 10:3. Kinetic analysis indicates that drug release mechanism was anomalous non-Fickian diffusion. Conclusion: Both Carbopol 974P and 934 can be used as rate-controlling agents in the formulation of tramadol HCl CR tablets. Appropriate selection of drug/polymer ratio can be applied effectively to modulate the dissolution rate of the drug.

Research paper thumbnail of Controlled Release Drug Delivery Systems Containing Diltiazem HCl: Effect of Polymer Concentration on In Vitro Drug Release Profiles

In this study, controlled release matrix tablets of diltiazem HCl were prepared by direct compres... more In this study, controlled release matrix tablets of diltiazem HCl were prepared by direct compression method using Ethocel as rate controlling polymer. The CR tablets of diltiazem HCl were formulated at different drug to polymer ratios to see the effect of polymer concentration on the release of drug during in vitro drug dissolution studies. Different physico-chemical tests were performed on matrix tablets to evaluate their suitability for in vitro and in vivo drug release performance. In vitro dissolution studies were performed in phosphate buffer pH 7.4 with PharmaTest Dissolution Apparatus, using USP method-I (rotating basket method) at a rotation speed of 100 rpm by maintaining the temperature constant at 37 ± 0.1 °C. Several kinetic models were used for evaluating the dissolution data to find out the drug transport mechanism from the polymeric tablets into dissolution medium which were found to be occurred both by swelling controlled mechanism as well as diffusion mechanism, exhibiting nearly zero order kinetics. In vivo evaluation of diltiazem HCl CR tablets was determined in rabbit serum according to randomized twoway crossover study design. Several pharmacokinetic parameters including plasma concentration time curve (AUC 0-∞ ), maximum plasma concentration (C max ), time to reach peak plasma concentration (T max ), elimination half life (T 1/2 ), and apparent volume of distribution (Vd/f) were estimated from the plasma concentration-time profile of individual rabbit. An optimized C max and extended T max were produced and a good correlation of in vivo and in vitro drug absorption (R 2 = 0.952) was observed.

Research paper thumbnail of GM Khan CV & List of Publications 2020a

CV, 2020

GM Khan CV & List of Publications 2020a

Research paper thumbnail of GM Khan CV & List of Publications

GM Khan CV & List of Publications, 2020

GM Khan CV & List of Publications

Research paper thumbnail of GM Khan CV & List of Publications 2021a

Curriculum Vitae, 2021

Curriculum Vitae and List of Publications of Prof. Dr. Gul Majid Khan, Vice Chancellor: Islamia C... more Curriculum Vitae and List of Publications of Prof. Dr. Gul Majid Khan, Vice Chancellor: Islamia College University, Peshawar & Tenured Professor: Department of Pharmacy, Quaid-i-Azam University, Islamabad