SUMMARY Solid lipid nanoparticles (SLN) are generally considered to be biocompatible. This study ... more SUMMARY Solid lipid nanoparticles (SLN) are generally considered to be biocompatible. This study aimed to evaluate the haemocompatabiltiy of SLN containing diclofenac in comparison to existing marketed injectables. SLNs based on stearic acid (SA) and glycerol monostearate (GMS) were developed. Both SLNs produced were with acceptable particle size for parenteral use. Surprisingly, at low concentrations SA-SLN caused greater haemolysis compared to the drug alone or the marketed formulations. This could be due to the surfactant-like nature of the free lipid. GMS-SLN masked the haemolysis of dicloenac and appeared more biocompatible than SA-SLN.
Recent reports have demonstrated that topical and systemic application of naltrexone markedly imp... more Recent reports have demonstrated that topical and systemic application of naltrexone markedly improves the characteristic signs of diabetic keratopathy; most notably, impaired corneal sensation and delayed wound repair. The aim of this study was to prepare and characterise non-ionic surfactant vesicles (niosomes) for the ocular drug delivery of naltrexone hydrochloride. The niosomes were prepared using the thin film hydration method and characterised using polarized light microscopy, cryo-scanning electron microscopy (Cryo-SEM), percent drug entrapment efficiency (EE %), laser light diffraction and differential scanning calorimetry (DSC). Two classes of non-ionic surfactants (sorbitan esters and polyoxyethylene alkyl ethers) were investigated. The results revealed that tuning of cholesterol concentrations can significantly alter the niosome's physical properties including sizes, EE% and membrane fluidity (thermo-responsiveness). The prepared vesicles were in the range of 7.0 +/-...
SUMMARY Chitosan nanoparticles loaded with 2oxothiazolidine-4-carboxylic acid (OTZ) were formulat... more SUMMARY Chitosan nanoparticles loaded with 2oxothiazolidine-4-carboxylic acid (OTZ) were formulated by ionic gelation method. The in vitro release of OTZ from the nanoparticles was quantified over 96 hours. Permeation of OTZ through excised bovine cornea mounted on a Franz cell diffusion apparatus was measured using HPLC. The lag time and the flux were 0.2 h and 3.05 μg/cm.h respectively. INTRODUCTION It has been estimated that more than 18 million people are affected by cataract (1). Senile cataract is an age related condition that affects the lens of the eye causing visual impairment (1). One of the reasons for cataract formation is the low levels of glutathione (GSH) which is the main endogenous antioxidant in the lens. Cysteine is a GSH precursor and its supplementation may increase the GSH level in the lens (1). However, cysteine is very unstable and toxic. A recent study suggested that OTZ, which is in turn a precursor of cysteine, can increase the cellular level of GSH (2). C...
The purpose of this study was to develop a simple model for prediction of corneal permeability of... more The purpose of this study was to develop a simple model for prediction of corneal permeability of structurally different drugs as a function of calculated molecular descriptors using artificial neural networks. A set of 45 compounds with experimentally derived values of corneal permeability (log C) was used to develop, test and validate a predictive model. Each compound was encoded with 1194 calculated molecular structure descriptors. A genetic algorithm was used to select a subset of descriptors that best describe corneal permeability coefficient log C and a supervised network with radial basis transfer function (RBF) was used to correlate calculated molecular descriptors with experimentally derived measures of corneal permeability. The best model, with 4 input descriptors and 12 hidden neurones was chosen, and the significance of the selected descriptors to corneal permeability was examined. Strong correlation of predicted with experimentally derived log C values (correlation coef...
Recent reports have demonstrated that topical and systemic application of naltrexone markedly imp... more Recent reports have demonstrated that topical and systemic application of naltrexone markedly improves the characteristic signs of diabetic keratopathy; most notably, impaired corneal sensation and delayed wound repair. The aim of this study was to prepare and characterise non-ionic surfactant vesicles (niosomes) for the ocular drug delivery of naltrexone hydrochloride. The niosomes were prepared using the thin film hydration method and characterised using polarized light microscopy, cryo-scanning electron microscopy (Cryo-SEM), percent drug entrapment efficiency (EE %), laser light diffraction and differential scanning calorimetry (DSC). Two classes of non-ionic surfactants (sorbitan esters and polyoxyethylene alkyl ethers) were investigated. The results revealed that tuning of cholesterol concentrations can significantly alter the niosome's physical properties including sizes, EE% and membrane fluidity (thermo-responsiveness). The prepared vesicles were in the range of 7.0 +/-...
Purpose. A genetic neural network (GNN) model was developed to predict the phase behavior of micr... more Purpose. A genetic neural network (GNN) model was developed to predict the phase behavior of microemulsion (ME), lamellar liquid crystal (LC), and coarse emulsion forming systems (W/O EM and O/W EM) depending on the content of separate components in the system and cosurfactant nature.
This manuscript reports (for the first time) on antibiotic-free polymeric inserts for the prevent... more This manuscript reports (for the first time) on antibiotic-free polymeric inserts for the prevention and/or treatment of bovine mastitis. Polyethylene oxide (PEO)-based inserts were prepared using different concentrations of various hydrophilic polymers and water-soluble and water-insoluble drug-release-modifying excipients. A simple and scalable melt-extrusion method was employed to prepare the inserts. The prepared inserts were characterised for their dimension, rheological and mechanical properties. The in vitro release of a model bacteriostatic drug (salicylic acid) from the prepared inserts was studied to demonstrate the effectiveness and reproducibility of the melt-extrusion manufacturing method. Further, the in vitro stability of the inserts was evaluated using gel permeation chromatography (GPC) to monitor any change in molecular weight under real-time and accelerated storage conditions. The investigated inserts were stable at accelerated storage conditions over a period of 6 months. PEO inserts have the potential to serve a dual purpose, act as a physical barrier against pathogens invading the teat canal of cows and possibly control the release of a drug.
Volume 2: Biomedical and Biotechnology Engineering, 2010
ABSTRACT Current asthma treatments using anti-inflammatory agents and airway smooth muscle (ASM) ... more ABSTRACT Current asthma treatments using anti-inflammatory agents and airway smooth muscle (ASM) relaxants are expensive, variable in effectiveness and are associated with several cardiovascular side effects. Previous in vitro experiments conducted on ASM tissues suggest that oscillations applied to contracted muscle result in a reduction in the contractile ability of the tissue. This study focuses on investigating the combined effects of muscle relaxants (bronchodilators) and length oscillations on the dynamics of contracted ASM. Isolated porcine tracheal smooth muscle tissues are contracted using Acetylcholine. Isoproterenol (Iso), a β-agonist, is used as a bronchodilator to relax the contracted ASM. Our results suggest that the combined effect of Iso and breathing oscillations is noted to be greater than the added effects of Iso and breathing alone. It can be proposed that breathing oscillations aid the relaxation of ASM by Isoproterenol.
The aim of the current study was to investigate the effect of different co-surfactants on the pha... more The aim of the current study was to investigate the effect of different co-surfactants on the phase behaviour of the pseudoternary system water:ethyl oleate:nonionic surfactant blend (sorbitan monolaurate/polyoxyethylene 20 sorbitan mono-oleate). Four aliphatic alcohols (1-propanol, 1-butanol, 1-hexanol and 1-octanol) and four 1, 2-alkanediols (1,2-propanediol, 1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol) were used. The co-surfactant-free system forms two different colloidal structures, a water-in-oil microemulsion (w/o ME) and lamellar liquid crystals (LC) and two coarse dispersions, water-in-oil (w/o EM) and oil-in-water (o/w EM) emulsions. Microemulsion region area (%ME), liquid crystalline region area (%LC), amount of amphiphile blend required to produce a balanced microemulsion (%AMPH) and amount of water solubilised (%W) were used as assessment criteria to evaluate the co-surfactants. Seven calculated physico-chemical descriptors were used to represent the different co-surfactants. 1-butanol, 1,2-hexanediol and 1, 2-octanediol produced balanced MEs capable of solubilising a high percentage of both oil and water. A similarity was observed between the descriptors attributed to 1-butanol and 1,2-hexanediol. The requirements of a co-surfactant molecule to produce a balanced microemulsion were: HLB value 7.0-8.0, a carbon backbone of 4-6 atoms, percentage carbon of 60-65%, percentage oxygen of 20-30%, logP value 0.2-0.9 and log 1/S (S: aqueous solubility) close to zero.
Abstract: Applicability of HPLC based models for calculating partition coefficient (logP) of ster... more Abstract: Applicability of HPLC based models for calculating partition coefficient (logP) of steroids was investigated. Retention time was used to calculate retention factor (logK'), isocratic (CHIi) and gradient (CHIg) Chromatography Hydrophobicity Index. CHIi was ...
2011 1st Middle East Conference on Biomedical Engineering, 2011
Airway hyperresponsiveness and obstruction are the major characteristics of asthma. Current asthm... more Airway hyperresponsiveness and obstruction are the major characteristics of asthma. Current asthma treatments using antiinflammatory agents and airway smooth muscle (ASM) relaxants are expensive, variable in effectiveness and are associated with several cardiovascular side effects. ASM behaviour in vitro has been studied by various researchers to possibly provide an explanation of its mechanical properties. Previous in vitro experiments conducted on
The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by the ... more The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by the scientists, whose names appear in this and the next few pages, in keeping the quality of the journal high. Their commitment to excellence is admirable and very much appreciated by ...
The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by scie... more The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by scientists, whose names appear in this and the next few pages, in keeping the quality of the journal high. Their commitment to excellence was admirable and very much appreciated by members of the pharmaceutical community. A special note of thanks goes to those reviewers who had reviewed more than five manuscripts. Their devotion to the journal, despite the multiple demands on their time, is extraordinary.
Liquid polymeric systems that can undergo phase change (sol to gel) upon administration into the ... more Liquid polymeric systems that can undergo phase change (sol to gel) upon administration into the teat canal of cow's mammary gland can serve as a physical barrier to invading pathogens and can also serve as a reservoir for controlled release of therapeutic agents. The aim of the study was to investigate the phase behavior, rheological and mechanical properties of selected in situ gelling systems. Six in situ gelling polymer formulations were identified using phase behavior studies. Rheological studies revealed pseudoplastic flow with thixotropy. All six formulations showed significantly different viscosity, pseudoplasticity and thixotropy values except for CMC1 and HPMC2 which where statistically similar. The gel strength was dependent on the solvent system used and amount of water in the system. These in situ gelling systems have the potential to serve as a platform for development of intramammary formulations intended for administration into the teat canal of the cow's mammary gland. They can serve as a physical barrier or a matrix for controlled drug release.
SUMMARY Solid lipid nanoparticles (SLN) are generally considered to be biocompatible. This study ... more SUMMARY Solid lipid nanoparticles (SLN) are generally considered to be biocompatible. This study aimed to evaluate the haemocompatabiltiy of SLN containing diclofenac in comparison to existing marketed injectables. SLNs based on stearic acid (SA) and glycerol monostearate (GMS) were developed. Both SLNs produced were with acceptable particle size for parenteral use. Surprisingly, at low concentrations SA-SLN caused greater haemolysis compared to the drug alone or the marketed formulations. This could be due to the surfactant-like nature of the free lipid. GMS-SLN masked the haemolysis of dicloenac and appeared more biocompatible than SA-SLN.
Recent reports have demonstrated that topical and systemic application of naltrexone markedly imp... more Recent reports have demonstrated that topical and systemic application of naltrexone markedly improves the characteristic signs of diabetic keratopathy; most notably, impaired corneal sensation and delayed wound repair. The aim of this study was to prepare and characterise non-ionic surfactant vesicles (niosomes) for the ocular drug delivery of naltrexone hydrochloride. The niosomes were prepared using the thin film hydration method and characterised using polarized light microscopy, cryo-scanning electron microscopy (Cryo-SEM), percent drug entrapment efficiency (EE %), laser light diffraction and differential scanning calorimetry (DSC). Two classes of non-ionic surfactants (sorbitan esters and polyoxyethylene alkyl ethers) were investigated. The results revealed that tuning of cholesterol concentrations can significantly alter the niosome's physical properties including sizes, EE% and membrane fluidity (thermo-responsiveness). The prepared vesicles were in the range of 7.0 +/-...
SUMMARY Chitosan nanoparticles loaded with 2oxothiazolidine-4-carboxylic acid (OTZ) were formulat... more SUMMARY Chitosan nanoparticles loaded with 2oxothiazolidine-4-carboxylic acid (OTZ) were formulated by ionic gelation method. The in vitro release of OTZ from the nanoparticles was quantified over 96 hours. Permeation of OTZ through excised bovine cornea mounted on a Franz cell diffusion apparatus was measured using HPLC. The lag time and the flux were 0.2 h and 3.05 μg/cm.h respectively. INTRODUCTION It has been estimated that more than 18 million people are affected by cataract (1). Senile cataract is an age related condition that affects the lens of the eye causing visual impairment (1). One of the reasons for cataract formation is the low levels of glutathione (GSH) which is the main endogenous antioxidant in the lens. Cysteine is a GSH precursor and its supplementation may increase the GSH level in the lens (1). However, cysteine is very unstable and toxic. A recent study suggested that OTZ, which is in turn a precursor of cysteine, can increase the cellular level of GSH (2). C...
The purpose of this study was to develop a simple model for prediction of corneal permeability of... more The purpose of this study was to develop a simple model for prediction of corneal permeability of structurally different drugs as a function of calculated molecular descriptors using artificial neural networks. A set of 45 compounds with experimentally derived values of corneal permeability (log C) was used to develop, test and validate a predictive model. Each compound was encoded with 1194 calculated molecular structure descriptors. A genetic algorithm was used to select a subset of descriptors that best describe corneal permeability coefficient log C and a supervised network with radial basis transfer function (RBF) was used to correlate calculated molecular descriptors with experimentally derived measures of corneal permeability. The best model, with 4 input descriptors and 12 hidden neurones was chosen, and the significance of the selected descriptors to corneal permeability was examined. Strong correlation of predicted with experimentally derived log C values (correlation coef...
Recent reports have demonstrated that topical and systemic application of naltrexone markedly imp... more Recent reports have demonstrated that topical and systemic application of naltrexone markedly improves the characteristic signs of diabetic keratopathy; most notably, impaired corneal sensation and delayed wound repair. The aim of this study was to prepare and characterise non-ionic surfactant vesicles (niosomes) for the ocular drug delivery of naltrexone hydrochloride. The niosomes were prepared using the thin film hydration method and characterised using polarized light microscopy, cryo-scanning electron microscopy (Cryo-SEM), percent drug entrapment efficiency (EE %), laser light diffraction and differential scanning calorimetry (DSC). Two classes of non-ionic surfactants (sorbitan esters and polyoxyethylene alkyl ethers) were investigated. The results revealed that tuning of cholesterol concentrations can significantly alter the niosome's physical properties including sizes, EE% and membrane fluidity (thermo-responsiveness). The prepared vesicles were in the range of 7.0 +/-...
Purpose. A genetic neural network (GNN) model was developed to predict the phase behavior of micr... more Purpose. A genetic neural network (GNN) model was developed to predict the phase behavior of microemulsion (ME), lamellar liquid crystal (LC), and coarse emulsion forming systems (W/O EM and O/W EM) depending on the content of separate components in the system and cosurfactant nature.
This manuscript reports (for the first time) on antibiotic-free polymeric inserts for the prevent... more This manuscript reports (for the first time) on antibiotic-free polymeric inserts for the prevention and/or treatment of bovine mastitis. Polyethylene oxide (PEO)-based inserts were prepared using different concentrations of various hydrophilic polymers and water-soluble and water-insoluble drug-release-modifying excipients. A simple and scalable melt-extrusion method was employed to prepare the inserts. The prepared inserts were characterised for their dimension, rheological and mechanical properties. The in vitro release of a model bacteriostatic drug (salicylic acid) from the prepared inserts was studied to demonstrate the effectiveness and reproducibility of the melt-extrusion manufacturing method. Further, the in vitro stability of the inserts was evaluated using gel permeation chromatography (GPC) to monitor any change in molecular weight under real-time and accelerated storage conditions. The investigated inserts were stable at accelerated storage conditions over a period of 6 months. PEO inserts have the potential to serve a dual purpose, act as a physical barrier against pathogens invading the teat canal of cows and possibly control the release of a drug.
Volume 2: Biomedical and Biotechnology Engineering, 2010
ABSTRACT Current asthma treatments using anti-inflammatory agents and airway smooth muscle (ASM) ... more ABSTRACT Current asthma treatments using anti-inflammatory agents and airway smooth muscle (ASM) relaxants are expensive, variable in effectiveness and are associated with several cardiovascular side effects. Previous in vitro experiments conducted on ASM tissues suggest that oscillations applied to contracted muscle result in a reduction in the contractile ability of the tissue. This study focuses on investigating the combined effects of muscle relaxants (bronchodilators) and length oscillations on the dynamics of contracted ASM. Isolated porcine tracheal smooth muscle tissues are contracted using Acetylcholine. Isoproterenol (Iso), a β-agonist, is used as a bronchodilator to relax the contracted ASM. Our results suggest that the combined effect of Iso and breathing oscillations is noted to be greater than the added effects of Iso and breathing alone. It can be proposed that breathing oscillations aid the relaxation of ASM by Isoproterenol.
The aim of the current study was to investigate the effect of different co-surfactants on the pha... more The aim of the current study was to investigate the effect of different co-surfactants on the phase behaviour of the pseudoternary system water:ethyl oleate:nonionic surfactant blend (sorbitan monolaurate/polyoxyethylene 20 sorbitan mono-oleate). Four aliphatic alcohols (1-propanol, 1-butanol, 1-hexanol and 1-octanol) and four 1, 2-alkanediols (1,2-propanediol, 1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol) were used. The co-surfactant-free system forms two different colloidal structures, a water-in-oil microemulsion (w/o ME) and lamellar liquid crystals (LC) and two coarse dispersions, water-in-oil (w/o EM) and oil-in-water (o/w EM) emulsions. Microemulsion region area (%ME), liquid crystalline region area (%LC), amount of amphiphile blend required to produce a balanced microemulsion (%AMPH) and amount of water solubilised (%W) were used as assessment criteria to evaluate the co-surfactants. Seven calculated physico-chemical descriptors were used to represent the different co-surfactants. 1-butanol, 1,2-hexanediol and 1, 2-octanediol produced balanced MEs capable of solubilising a high percentage of both oil and water. A similarity was observed between the descriptors attributed to 1-butanol and 1,2-hexanediol. The requirements of a co-surfactant molecule to produce a balanced microemulsion were: HLB value 7.0-8.0, a carbon backbone of 4-6 atoms, percentage carbon of 60-65%, percentage oxygen of 20-30%, logP value 0.2-0.9 and log 1/S (S: aqueous solubility) close to zero.
Abstract: Applicability of HPLC based models for calculating partition coefficient (logP) of ster... more Abstract: Applicability of HPLC based models for calculating partition coefficient (logP) of steroids was investigated. Retention time was used to calculate retention factor (logK'), isocratic (CHIi) and gradient (CHIg) Chromatography Hydrophobicity Index. CHIi was ...
2011 1st Middle East Conference on Biomedical Engineering, 2011
Airway hyperresponsiveness and obstruction are the major characteristics of asthma. Current asthm... more Airway hyperresponsiveness and obstruction are the major characteristics of asthma. Current asthma treatments using antiinflammatory agents and airway smooth muscle (ASM) relaxants are expensive, variable in effectiveness and are associated with several cardiovascular side effects. ASM behaviour in vitro has been studied by various researchers to possibly provide an explanation of its mechanical properties. Previous in vitro experiments conducted on
The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by the ... more The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by the scientists, whose names appear in this and the next few pages, in keeping the quality of the journal high. Their commitment to excellence is admirable and very much appreciated by ...
The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by scie... more The editorial team of Pharmaceutical Research wishes to acknowledge the vital role played by scientists, whose names appear in this and the next few pages, in keeping the quality of the journal high. Their commitment to excellence was admirable and very much appreciated by members of the pharmaceutical community. A special note of thanks goes to those reviewers who had reviewed more than five manuscripts. Their devotion to the journal, despite the multiple demands on their time, is extraordinary.
Liquid polymeric systems that can undergo phase change (sol to gel) upon administration into the ... more Liquid polymeric systems that can undergo phase change (sol to gel) upon administration into the teat canal of cow's mammary gland can serve as a physical barrier to invading pathogens and can also serve as a reservoir for controlled release of therapeutic agents. The aim of the study was to investigate the phase behavior, rheological and mechanical properties of selected in situ gelling systems. Six in situ gelling polymer formulations were identified using phase behavior studies. Rheological studies revealed pseudoplastic flow with thixotropy. All six formulations showed significantly different viscosity, pseudoplasticity and thixotropy values except for CMC1 and HPMC2 which where statistically similar. The gel strength was dependent on the solvent system used and amount of water in the system. These in situ gelling systems have the potential to serve as a platform for development of intramammary formulations intended for administration into the teat canal of the cow's mammary gland. They can serve as a physical barrier or a matrix for controlled drug release.
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