Kaleem Ullah | COMSATS Institute of Information Technology,Abbottabad,Pakistan (original) (raw)
Papers by Kaleem Ullah
Current Pharmaceutical Biotechnology, 2020
Background: Staphylococcus aureus (S. aureus) is the most common infectious agent in the communit... more Background: Staphylococcus aureus (S. aureus) is the most common infectious agent in the community and hospitals. Infections with S. aureus are now becoming difficult to be treated by using conventional antibiotics due to its emerging methicillin-resistant S. aureus (MRSA) strain. Objective: In the present study, MRSA was isolated from clinical samples and evaluated for resistance against different antibiotics, TiO2 nanoparticles, and their combinations. Methods: Clinical samples were collected from Ayub Medical Complex (AMC), Abbottabad, Pakistan, and identified by different biochemical tests and polymerase chain reactions (PCR). Kirby-Bauer disk diffusion method was performed to evaluate antimicrobial susceptibility. Minimum Inhibitory Concentration (MIC) of ampicillin, ciprofloxacin, erythromycin, and vancomycin was found out by agar dilution method while the broth dilution method was used for the MIC of TiO2 nanoparticles and their combinations with erythromycin. Results: All 13...
International Journal of Pharmaceutics, 2019
This study describes the fabrication of chemically crosslinked pectin-based LA-co-MAA hydrogels t... more This study describes the fabrication of chemically crosslinked pectin-based LA-co-MAA hydrogels through free radical polymerization technique for the colonic delivery of oxaliplatin. Methylene bisacrylamide was used as a crosslinking agent and ammonium persulfate as an initiator. The successful fabrication and drug loading were confirmed through Fourier transform infrared spectroscopy (FTIR). The thermal investigations through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) suggested the higher thermal stability of the unloaded and OXP-loaded formulations as compared to the raw materials. X-ray diffraction (XRD) analysis showed a decrease in crystallinity after crosslinking. The swelling, drug loading, and drug release were increased with an increase in the concentration of pectin and lactic acid (LA) while methacrylic acid (MAA) displayed an inverse behavior. The in-vitro 2 biodegradability was evaluated against lysozyme and collagenase. The results showed that the hydrogels were stable against blank PBS as compared to lysozyme and collagenase. MTT-assay proved that the blank hydrogels were cytocompatible while free OXP and OXP-loaded hydrogels displayed dose-dependent effect against Vero, MCF-7, and HCT-116 cell lines. The oral tolerability study in rabbits confirmed that the hydrogel dispersion was well-tolerable up to 3650 mg/kg of body weight without causing any histopathological or hematological changes when compared with the control group.
International Journal of Pharmaceutics, 2018
In present investigation, gelatin-based (AA-co-AMPS) hydrogels were prepared using N, N'-Methylen... more In present investigation, gelatin-based (AA-co-AMPS) hydrogels were prepared using N, N'-Methylenebisacrylamide (MBA) as a cross-linker and ammonium per sulfate (APS) as an initiator. The successful crosslinking and network formation was confirmed by Fourier transform infrared spectroscopy (FT IR). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) investigations proved the higher thermal stability and successful entrapment of oxaliplatin (OXP) in the polymeric network. X-ray diffraction (XRD) confirmed the loss in crystallinity of the drug after loading in the hydrogel. Scanning electron microscopy (SEM) revealed the porous surface of the hydrogel. The newly formed hydrogels were responsive to change in pH. The swelling, drug loading and drug release was increased with increase in concentration of acrylic acid (AA) while gelatin and 2-acrylamido 2-methylpronesulfonic acid (AMPS) were found to act inversely. The in-vitro enzymatic degradation study showed that the blank hydrogels were more stable against the blank PBS than the collagenase and lysozyme. MTT-assay proved that the blank hydrogels were cyto-compatible while free OXP as well as OXP-loaded hydrogels showed dose dependent controlled cytotoxicity against Vero, MCF-7 and HCT-116 cell lines. The preliminary safety evaluation and oral tolerability showed that the hydrogel suspension was biocompatible and well tolerable upto 4000 mg/kg of body weight without causing any hematological or histopathological changes in rabbits.
International journal of biological macromolecules, 2018
The aim of this study was to prepare hydroxypropyl-methyl cellulose (HPMC)-K15 based hydrogels vi... more The aim of this study was to prepare hydroxypropyl-methyl cellulose (HPMC)-K15 based hydrogels via free radical polymerization using 2‑acrylamido-2‑methyl propane sulphonic acid (AMPS) as a monomer and N,N'-methylene bisacrylamide (MBAAm) as a crosslinker. Loxoprofen sodium was chosen as a model drug and successfully loaded in hydrogel discs. Sol-gel, porosity, loading efficiency, and the in vitro drug release analysis were carried out to evaluate its drug delivery potential. HMPC-g-poly(AMPS) hydrogels were characterized by using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) approaches. Maximum swelling and drug release were observed at pH 7.4. Kinetic modelling suggested that drug release followed first-order kinetics with the non-Fickian mechanism. FTIR and DSC confirmed the formation of new hydrogels. SEM micrographs confirmed uneven, rough, and partially porous type of surface. These results s...
Current Drug Delivery, 2019
Objective: The aim of the present study was to design an efficient delivery system with an antici... more Objective: The aim of the present study was to design an efficient delivery system with an anticipated swelling and drug release properties for a prolonged drug release as well as to target colon for various hydrophilic drugs. Methods: For this purpose, the pH-responsive hydrogel comprising a combination of Eudragit and acrylic acid was formed. The hydrogels were characterized for spectral (FTIR), thermal (TGA/DSC), structural (XRD), and morphological (SEM) investigations. Oral tolerability was assessed in rabbits for biocompatibility and oral use of the prepared hydrogels. Results: The results showed that an increased incorporation of Eudragit and cross-linking agent retorted the swelling, drug loading, and drug release properties at both acid (pH 1.2) and basic pH (pH 6.8 and 7.4) , while acrylic acid presented the inverse results. The oral tolerability and toxicity studies depicted that the developed hydrogels were safe up to 3800 mg/kg body weight and caused no hematological or ...
The development and introduction of injectable biomaterials and the identification of methods thr... more The development and introduction of injectable biomaterials and the identification of methods through which materials may form in situ are currently the topics of interest in materials science, specifically in the field of biomaterials. Over the last few decades, hydrogels which refers to the swellable polymeric matrices have gained wide attention due to their excellent characteristics such as swelling in different media, pH and temperature sensitivity, and sensitivity to other stimuli. Nowadays, injectable hydrogels have widely been studied due to their excellent insitu gelation at body temperature. These injectable insitu gels serve as depot system which ensures the local and systemic drug and gene delivery. These insitu gels also protect the proteins and peptide drugs invivo from environmental effect. The current review is made to report latest extensive literature regarding hydrogels, their classification, synthesis methods, structure of hydrogel network, methods of crosslinking, environment-sensitive hydrogel system, drug loading, and release, hydrogels as biosensors and applications of hydrogels.
Current Pharmaceutical Biotechnology, 2020
Background: Staphylococcus aureus (S. aureus) is the most common infectious agent in the communit... more Background: Staphylococcus aureus (S. aureus) is the most common infectious agent in the community and hospitals. Infections with S. aureus are now becoming difficult to be treated by using conventional antibiotics due to its emerging methicillin-resistant S. aureus (MRSA) strain. Objective: In the present study, MRSA was isolated from clinical samples and evaluated for resistance against different antibiotics, TiO2 nanoparticles, and their combinations. Methods: Clinical samples were collected from Ayub Medical Complex (AMC), Abbottabad, Pakistan, and identified by different biochemical tests and polymerase chain reactions (PCR). Kirby-Bauer disk diffusion method was performed to evaluate antimicrobial susceptibility. Minimum Inhibitory Concentration (MIC) of ampicillin, ciprofloxacin, erythromycin, and vancomycin was found out by agar dilution method while the broth dilution method was used for the MIC of TiO2 nanoparticles and their combinations with erythromycin. Results: All 13...
International Journal of Pharmaceutics, 2019
This study describes the fabrication of chemically crosslinked pectin-based LA-co-MAA hydrogels t... more This study describes the fabrication of chemically crosslinked pectin-based LA-co-MAA hydrogels through free radical polymerization technique for the colonic delivery of oxaliplatin. Methylene bisacrylamide was used as a crosslinking agent and ammonium persulfate as an initiator. The successful fabrication and drug loading were confirmed through Fourier transform infrared spectroscopy (FTIR). The thermal investigations through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) suggested the higher thermal stability of the unloaded and OXP-loaded formulations as compared to the raw materials. X-ray diffraction (XRD) analysis showed a decrease in crystallinity after crosslinking. The swelling, drug loading, and drug release were increased with an increase in the concentration of pectin and lactic acid (LA) while methacrylic acid (MAA) displayed an inverse behavior. The in-vitro 2 biodegradability was evaluated against lysozyme and collagenase. The results showed that the hydrogels were stable against blank PBS as compared to lysozyme and collagenase. MTT-assay proved that the blank hydrogels were cytocompatible while free OXP and OXP-loaded hydrogels displayed dose-dependent effect against Vero, MCF-7, and HCT-116 cell lines. The oral tolerability study in rabbits confirmed that the hydrogel dispersion was well-tolerable up to 3650 mg/kg of body weight without causing any histopathological or hematological changes when compared with the control group.
International Journal of Pharmaceutics, 2018
In present investigation, gelatin-based (AA-co-AMPS) hydrogels were prepared using N, N'-Methylen... more In present investigation, gelatin-based (AA-co-AMPS) hydrogels were prepared using N, N'-Methylenebisacrylamide (MBA) as a cross-linker and ammonium per sulfate (APS) as an initiator. The successful crosslinking and network formation was confirmed by Fourier transform infrared spectroscopy (FT IR). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) investigations proved the higher thermal stability and successful entrapment of oxaliplatin (OXP) in the polymeric network. X-ray diffraction (XRD) confirmed the loss in crystallinity of the drug after loading in the hydrogel. Scanning electron microscopy (SEM) revealed the porous surface of the hydrogel. The newly formed hydrogels were responsive to change in pH. The swelling, drug loading and drug release was increased with increase in concentration of acrylic acid (AA) while gelatin and 2-acrylamido 2-methylpronesulfonic acid (AMPS) were found to act inversely. The in-vitro enzymatic degradation study showed that the blank hydrogels were more stable against the blank PBS than the collagenase and lysozyme. MTT-assay proved that the blank hydrogels were cyto-compatible while free OXP as well as OXP-loaded hydrogels showed dose dependent controlled cytotoxicity against Vero, MCF-7 and HCT-116 cell lines. The preliminary safety evaluation and oral tolerability showed that the hydrogel suspension was biocompatible and well tolerable upto 4000 mg/kg of body weight without causing any hematological or histopathological changes in rabbits.
International journal of biological macromolecules, 2018
The aim of this study was to prepare hydroxypropyl-methyl cellulose (HPMC)-K15 based hydrogels vi... more The aim of this study was to prepare hydroxypropyl-methyl cellulose (HPMC)-K15 based hydrogels via free radical polymerization using 2‑acrylamido-2‑methyl propane sulphonic acid (AMPS) as a monomer and N,N'-methylene bisacrylamide (MBAAm) as a crosslinker. Loxoprofen sodium was chosen as a model drug and successfully loaded in hydrogel discs. Sol-gel, porosity, loading efficiency, and the in vitro drug release analysis were carried out to evaluate its drug delivery potential. HMPC-g-poly(AMPS) hydrogels were characterized by using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) approaches. Maximum swelling and drug release were observed at pH 7.4. Kinetic modelling suggested that drug release followed first-order kinetics with the non-Fickian mechanism. FTIR and DSC confirmed the formation of new hydrogels. SEM micrographs confirmed uneven, rough, and partially porous type of surface. These results s...
Current Drug Delivery, 2019
Objective: The aim of the present study was to design an efficient delivery system with an antici... more Objective: The aim of the present study was to design an efficient delivery system with an anticipated swelling and drug release properties for a prolonged drug release as well as to target colon for various hydrophilic drugs. Methods: For this purpose, the pH-responsive hydrogel comprising a combination of Eudragit and acrylic acid was formed. The hydrogels were characterized for spectral (FTIR), thermal (TGA/DSC), structural (XRD), and morphological (SEM) investigations. Oral tolerability was assessed in rabbits for biocompatibility and oral use of the prepared hydrogels. Results: The results showed that an increased incorporation of Eudragit and cross-linking agent retorted the swelling, drug loading, and drug release properties at both acid (pH 1.2) and basic pH (pH 6.8 and 7.4) , while acrylic acid presented the inverse results. The oral tolerability and toxicity studies depicted that the developed hydrogels were safe up to 3800 mg/kg body weight and caused no hematological or ...
The development and introduction of injectable biomaterials and the identification of methods thr... more The development and introduction of injectable biomaterials and the identification of methods through which materials may form in situ are currently the topics of interest in materials science, specifically in the field of biomaterials. Over the last few decades, hydrogels which refers to the swellable polymeric matrices have gained wide attention due to their excellent characteristics such as swelling in different media, pH and temperature sensitivity, and sensitivity to other stimuli. Nowadays, injectable hydrogels have widely been studied due to their excellent insitu gelation at body temperature. These injectable insitu gels serve as depot system which ensures the local and systemic drug and gene delivery. These insitu gels also protect the proteins and peptide drugs invivo from environmental effect. The current review is made to report latest extensive literature regarding hydrogels, their classification, synthesis methods, structure of hydrogel network, methods of crosslinking, environment-sensitive hydrogel system, drug loading, and release, hydrogels as biosensors and applications of hydrogels.