Ian Harding - Academia.edu (original) (raw)
Papers by Ian Harding
International journal of pharmaceutics, Jan 30, 2016
Stearic acid-based solid lipid nanoparticles (SLNs) were prepared using the microwave assisted on... more Stearic acid-based solid lipid nanoparticles (SLNs) were prepared using the microwave assisted one-pot microemulsions procedure pioneered by our group. In this study, non-steroidal anti-inflammatory drugs (NSAIDs) including indomethacin, ketoprofen and nimesulide were selected as ideal "test" drugs, based on their poor water solubility. The model drugs were incorporated within the SLNs by the microwave-assisted procedure at the time of SLN production. The microwave-produced drug-loaded SLNs were evaluated in terms of their physicochemical characteristics, drug release behavior and their uptake into against A549 cell line (human lung epithelial cells). The microwave-produced drug-loaded SLNs had a small particle size distribution, negative zeta potential and high encapsulation efficiency. The drug release studies were consistent with a core-shell structure of SLNs (probably a drug-loaded shell) which results in biphasic drug release from the SLNs. The drug release kinetics ...
Fungal genetics and biology : FG & B, May 4, 2016
To increase the efficiency of winery-derived biomass biodegradation, grape pomace was ultrasonica... more To increase the efficiency of winery-derived biomass biodegradation, grape pomace was ultrasonicated for 20min in the presence of 0.25M, 0.5Mand1.0MKOH and 1.0MNaOH. This was followed by treatment with a 1:1 (v/v) mix of crude enzyme preparation derived from Phanerochaete chrysosporium and Trametes versicolor for 18h and a further 18h treatment with a 60:14:4:2 percent ratio combination of enzymes derived from Aspergillus niger: Penicillium chrysogenum: Trichoderma harzianum: P. citrinum, repsectively. Process efficiency was evaluated by its comparison to biological only mixed fungal degradation over 16days. Ultrasonication treatment with 0.5MKOH followed by mixed enzyme treatment yielded the highest lignin degradation of about 13%. Cellulase, β-glucosidase, xylanase, laccase and lignin peroxidase activities of 77.9, 476, 5,390.5, 66.7 and 29,230.7U/mL, respectively, were observed during biomass degradation. Gas chromatography-mass spectrometry (GC-MS) analysis of the degraded mater...
ABSTRACT What are lipid nanoparticles? How are they structured? How are they formed? What techniq... more ABSTRACT What are lipid nanoparticles? How are they structured? How are they formed? What techniques are best to characterize them? How great is their potential as drug delivery systems? These questions and more are answered in this comprehensive and highly readable work on lipid nanoparticles. This work sets out to provide the reader with a clear and understandable understanding of the current practices in formulation, characterization and drug delivery of lipid nanoparticles. A comprehensive description of the current understanding of synthesis, characterization, stability optimization and drug incorporation of solid lipid nanoparticles is provided. Nanoparticles have attracted great interest over the past few decades with almost exponential growth in their research and application. Their small particle size and subsequent high surface area make them ideal in many uses, but particularly as drug carrier systems. Nanoparticles made from lipids are especially attractive because of their enhanced biocompatibility imparted by the lipid. The work provides a detailed description of the types of lipid nanoparticles available (e.g. SLN, NLC, LDC, PLN) and how they range from imperfect crystalline to amorphous in structure. Current thoughts on where drugs are situated (e.g. in the core, or at the interface) and how this can be manipulated are discussed. The many techniques for production, including the author’s own variant of microwave heating, are fully discussed. Techniques for measuring arguably the most important characteristics of particle size and polydispersity are discussed, along with techniques to measure crystallinity, shape and drug capacity. Finally, a full chapter on techniques for measuring stability, both in the absence and presence of drugs, is discussed, along with suggestions on how to optimize that stability. This work appeals to students of colloid science, practitioners of research into drug delivery and academics alike.
Langmuir, 1993
Page 1. Langmuir 1993,9, 3057-3062 3057 Adsorption and Coprecipitation of Multiple Heavy Metal Io... more Page 1. Langmuir 1993,9, 3057-3062 3057 Adsorption and Coprecipitation of Multiple Heavy Metal Ions onto the Hydrated Oxides of Iron and Chromium Russell J. Crawford,' Ian H. Harding, and David E. Mainwaring Centre ...
Langmuir, 1993
Page 1. 3050 Langmuir 1993,9, 3050-3056 Adsorption and Coprecipitation of Single Heavy Metal Ions... more Page 1. 3050 Langmuir 1993,9, 3050-3056 Adsorption and Coprecipitation of Single Heavy Metal Ions onto the Hydrated Oxides of Iron and Chromium Russell J. Crawford,; Ian H. Harding, and David E. Mainwaring Centre for ...
Colloid and Polymer Science, 1985
Amphoteric polystyrene latex colloids were prepared by the "emulsifier-free" emulsion polymerizat... more Amphoteric polystyrene latex colloids were prepared by the "emulsifier-free" emulsion polymerization of styrene. Two co-monomers, methacrylic acid (MA) (anionic) and dimethyl aminoethyl methacrylate (DMAM) (cationic) were used to promote the amphoteric nature of the resultant surfaces. Parameters such as particle size and the isoelectric point (IEP) were measured as a function of polymerization recipe. Particle size decreased with increasing initiator concentration according to the equation: log [d~] =-0.67 log [I] + 0.316 where dw is the weight average particle diameter and I is the concentration of initiator (potassium persulphate). The particle size also decreased with increasing temperature, increasing pH and addition of surfactant. Particle size was unaffected by the methacrylic acid content. The isoelectric point pH was decreased on decreasing initiator concentration and on increasing methacrylic acid content. The polymerization pathway was deduced to involve the cationic DMAM during the initiation phase and to involve the anionic MA as well as styrene, during the growth stage. A full polymerization pathway involving the formation of"oligomeric DMAM micelles" was postulated.
International journal of pharmaceutics, Jan 30, 2016
Stearic acid-based solid lipid nanoparticles (SLNs) were prepared using the microwave assisted on... more Stearic acid-based solid lipid nanoparticles (SLNs) were prepared using the microwave assisted one-pot microemulsions procedure pioneered by our group. In this study, non-steroidal anti-inflammatory drugs (NSAIDs) including indomethacin, ketoprofen and nimesulide were selected as ideal "test" drugs, based on their poor water solubility. The model drugs were incorporated within the SLNs by the microwave-assisted procedure at the time of SLN production. The microwave-produced drug-loaded SLNs were evaluated in terms of their physicochemical characteristics, drug release behavior and their uptake into against A549 cell line (human lung epithelial cells). The microwave-produced drug-loaded SLNs had a small particle size distribution, negative zeta potential and high encapsulation efficiency. The drug release studies were consistent with a core-shell structure of SLNs (probably a drug-loaded shell) which results in biphasic drug release from the SLNs. The drug release kinetics ...
Fungal genetics and biology : FG & B, May 4, 2016
To increase the efficiency of winery-derived biomass biodegradation, grape pomace was ultrasonica... more To increase the efficiency of winery-derived biomass biodegradation, grape pomace was ultrasonicated for 20min in the presence of 0.25M, 0.5Mand1.0MKOH and 1.0MNaOH. This was followed by treatment with a 1:1 (v/v) mix of crude enzyme preparation derived from Phanerochaete chrysosporium and Trametes versicolor for 18h and a further 18h treatment with a 60:14:4:2 percent ratio combination of enzymes derived from Aspergillus niger: Penicillium chrysogenum: Trichoderma harzianum: P. citrinum, repsectively. Process efficiency was evaluated by its comparison to biological only mixed fungal degradation over 16days. Ultrasonication treatment with 0.5MKOH followed by mixed enzyme treatment yielded the highest lignin degradation of about 13%. Cellulase, β-glucosidase, xylanase, laccase and lignin peroxidase activities of 77.9, 476, 5,390.5, 66.7 and 29,230.7U/mL, respectively, were observed during biomass degradation. Gas chromatography-mass spectrometry (GC-MS) analysis of the degraded mater...
ABSTRACT What are lipid nanoparticles? How are they structured? How are they formed? What techniq... more ABSTRACT What are lipid nanoparticles? How are they structured? How are they formed? What techniques are best to characterize them? How great is their potential as drug delivery systems? These questions and more are answered in this comprehensive and highly readable work on lipid nanoparticles. This work sets out to provide the reader with a clear and understandable understanding of the current practices in formulation, characterization and drug delivery of lipid nanoparticles. A comprehensive description of the current understanding of synthesis, characterization, stability optimization and drug incorporation of solid lipid nanoparticles is provided. Nanoparticles have attracted great interest over the past few decades with almost exponential growth in their research and application. Their small particle size and subsequent high surface area make them ideal in many uses, but particularly as drug carrier systems. Nanoparticles made from lipids are especially attractive because of their enhanced biocompatibility imparted by the lipid. The work provides a detailed description of the types of lipid nanoparticles available (e.g. SLN, NLC, LDC, PLN) and how they range from imperfect crystalline to amorphous in structure. Current thoughts on where drugs are situated (e.g. in the core, or at the interface) and how this can be manipulated are discussed. The many techniques for production, including the author’s own variant of microwave heating, are fully discussed. Techniques for measuring arguably the most important characteristics of particle size and polydispersity are discussed, along with techniques to measure crystallinity, shape and drug capacity. Finally, a full chapter on techniques for measuring stability, both in the absence and presence of drugs, is discussed, along with suggestions on how to optimize that stability. This work appeals to students of colloid science, practitioners of research into drug delivery and academics alike.
Langmuir, 1993
Page 1. Langmuir 1993,9, 3057-3062 3057 Adsorption and Coprecipitation of Multiple Heavy Metal Io... more Page 1. Langmuir 1993,9, 3057-3062 3057 Adsorption and Coprecipitation of Multiple Heavy Metal Ions onto the Hydrated Oxides of Iron and Chromium Russell J. Crawford,' Ian H. Harding, and David E. Mainwaring Centre ...
Langmuir, 1993
Page 1. 3050 Langmuir 1993,9, 3050-3056 Adsorption and Coprecipitation of Single Heavy Metal Ions... more Page 1. 3050 Langmuir 1993,9, 3050-3056 Adsorption and Coprecipitation of Single Heavy Metal Ions onto the Hydrated Oxides of Iron and Chromium Russell J. Crawford,; Ian H. Harding, and David E. Mainwaring Centre for ...
Colloid and Polymer Science, 1985
Amphoteric polystyrene latex colloids were prepared by the "emulsifier-free" emulsion polymerizat... more Amphoteric polystyrene latex colloids were prepared by the "emulsifier-free" emulsion polymerization of styrene. Two co-monomers, methacrylic acid (MA) (anionic) and dimethyl aminoethyl methacrylate (DMAM) (cationic) were used to promote the amphoteric nature of the resultant surfaces. Parameters such as particle size and the isoelectric point (IEP) were measured as a function of polymerization recipe. Particle size decreased with increasing initiator concentration according to the equation: log [d~] =-0.67 log [I] + 0.316 where dw is the weight average particle diameter and I is the concentration of initiator (potassium persulphate). The particle size also decreased with increasing temperature, increasing pH and addition of surfactant. Particle size was unaffected by the methacrylic acid content. The isoelectric point pH was decreased on decreasing initiator concentration and on increasing methacrylic acid content. The polymerization pathway was deduced to involve the cationic DMAM during the initiation phase and to involve the anionic MA as well as styrene, during the growth stage. A full polymerization pathway involving the formation of"oligomeric DMAM micelles" was postulated.