S. Gardyne | University of Waikato (original) (raw)
Papers by S. Gardyne
Results in Pharma Sciences, 2011
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](Journal of Organometallic Chemistry, 2003
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Results in Pharma Sciences, 2011
Eight bioactive drug compounds (abamectin, amoxicillin, dexamethasone, dexamethasone valerate, ke... more Eight bioactive drug compounds (abamectin, amoxicillin, dexamethasone, dexamethasone valerate, ketoprofen, melatonin, oestradiol 17b, and oestradiol benzoate) were combined via melt extrusion and disc pressing processes with a polycaprolactone (PCL) matrix and were then evaluated and compared via membrane diffusion and Hanson dissolution studies. This investigation was to determine the potential of this matrix to act as a controlled release drug delivery vehicle for a number of drugs not previously combined with PCL in a melt extrusion mix. The inclusion of the progesterone/PCL system, for which the drug release behaviour has been well studied before was intended for comparison with the PCL systems incorporating drugs that have received little research attention in the past. Initial studies centred on an evaluation of the permeation ability of the bioactive drugs dissolved in aqueous cyclodextrin solutions through a poly(e-caprolactone) (PCL) membrane using Valia-Chien side-by-side cells. Permeation rates were mostly low and found to range from 0 to 122 mg h À 1 with only ketoprofen, melatonin, and progesterone displaying rates exceeding 20 mg h À 1 . Hanson dissolution release profiles in aqueous alcohol were subsequently measured for the 9 melt extruded PCL/drug combinations and led to Hanson release rates of 0-556 mg cm À 2 h À 0.5 with dexamethasone, dexamethasone valerate, ketoprofen, melatonin, and progesterone giving values exceeding 100 mg cm À 2 h À 0.5 . A number of drugs such as the dexamethasones probably performed better than they did in the permeability rate measurements because of the less polar aqueous alcoholic solvent used. In searching for useful correlations between the drug physicochemical properties and release rate, only a moderate correlation (R 2 ¼ 0.5675) between Hanson dissolution release rate and permeation rate was found. This suggests that the release rate and the permeation are both controlled by the rate of drug diffusion through the PCL with release rate involving an additional dissolution process (of the drug) before permeation occurs accounting for the moderate correlation. In general, of the eight drugs considered, it was clear that the oestradiol-based drugs, abamectin, and amoxicillin were generally not suited to drug delivery via PCL under the conditions used. However, ketoprofen was found to be very suitable as a drug candidate for melt extrusion with PCL with dexamethasone valerate, dexamethasone, and melatonin also showing potential as candidates though to a much lesser extent. (S.J. Gardyne), m.mucalo@waikato.ac.nz (M.R. Mucalo), m.rathbone@griffith.edu.au (M.J. Rathbone). 1 Tel.: þ64 7 838 4466x6004. 2 Tel.: þ61 7 552 8313; fax: þ61 7 5552 8804. Results in Pharma Sciences 1 (2011) 80-87
Results in Pharma Sciences, 2011
Journal of Organometallic Chemistry, 2003
RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...
Results in Pharma Sciences, 2011
Eight bioactive drug compounds (abamectin, amoxicillin, dexamethasone, dexamethasone valerate, ke... more Eight bioactive drug compounds (abamectin, amoxicillin, dexamethasone, dexamethasone valerate, ketoprofen, melatonin, oestradiol 17b, and oestradiol benzoate) were combined via melt extrusion and disc pressing processes with a polycaprolactone (PCL) matrix and were then evaluated and compared via membrane diffusion and Hanson dissolution studies. This investigation was to determine the potential of this matrix to act as a controlled release drug delivery vehicle for a number of drugs not previously combined with PCL in a melt extrusion mix. The inclusion of the progesterone/PCL system, for which the drug release behaviour has been well studied before was intended for comparison with the PCL systems incorporating drugs that have received little research attention in the past. Initial studies centred on an evaluation of the permeation ability of the bioactive drugs dissolved in aqueous cyclodextrin solutions through a poly(e-caprolactone) (PCL) membrane using Valia-Chien side-by-side cells. Permeation rates were mostly low and found to range from 0 to 122 mg h À 1 with only ketoprofen, melatonin, and progesterone displaying rates exceeding 20 mg h À 1 . Hanson dissolution release profiles in aqueous alcohol were subsequently measured for the 9 melt extruded PCL/drug combinations and led to Hanson release rates of 0-556 mg cm À 2 h À 0.5 with dexamethasone, dexamethasone valerate, ketoprofen, melatonin, and progesterone giving values exceeding 100 mg cm À 2 h À 0.5 . A number of drugs such as the dexamethasones probably performed better than they did in the permeability rate measurements because of the less polar aqueous alcoholic solvent used. In searching for useful correlations between the drug physicochemical properties and release rate, only a moderate correlation (R 2 ¼ 0.5675) between Hanson dissolution release rate and permeation rate was found. This suggests that the release rate and the permeation are both controlled by the rate of drug diffusion through the PCL with release rate involving an additional dissolution process (of the drug) before permeation occurs accounting for the moderate correlation. In general, of the eight drugs considered, it was clear that the oestradiol-based drugs, abamectin, and amoxicillin were generally not suited to drug delivery via PCL under the conditions used. However, ketoprofen was found to be very suitable as a drug candidate for melt extrusion with PCL with dexamethasone valerate, dexamethasone, and melatonin also showing potential as candidates though to a much lesser extent. (S.J. Gardyne), m.mucalo@waikato.ac.nz (M.R. Mucalo), m.rathbone@griffith.edu.au (M.J. Rathbone). 1 Tel.: þ64 7 838 4466x6004. 2 Tel.: þ61 7 552 8313; fax: þ61 7 5552 8804. Results in Pharma Sciences 1 (2011) 80-87