Efficacy of sustained-release novel bupivacaine formulations in sheep : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies (MVS) Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand

dc.contributor.authorSahebjam, Farzin
dc.date.accessioned2017-12-07T00:25:28Z
dc.date.available2017-12-07T00:25:28Z
dc.date.issued2017
dc.description.abstractThe objective of this thesis was to prepare and assess several formulations of the local anaesthetic bupivacaine to achieve a longer duration of action. Intralipid® emulsion (a soybean oil emulsion) and collagen combined with titanium oxide nanoparticles were used to develop slow release bupivacaine formulation. These formulations were tested both in vitro as a pilot study and in vivo in sheep. Collagen was extracted from bovine limed split hide (a by-product of the leather industry). The collagen as a 1% solution was mixed with bupivacaine hydrochloride 0.5% aqueous solution (Marcain® 0.5%, AstraZeneca, New Zealand) giving a final concentration of 0.25% bupivacaine. Intralipid® (20%, Fresenius Kabi Australia) and bupivacaine 0.5% were mixed resulting in a 0.25% bupivacaine lipid emulsion. Both formulations were tested in vitro pilot study for the release of bupivacaine through a dialysis membrane. The concentration of bupivacaine in the dialysate was measured using High-Performance Liquid Chromatography (HPLC). In the animal studies, 18 sheep were used to compare bupivacaine (control) and bupivacaine-Intralipid®, and another 18 sheep for commercial bupivacaine (control) and collagen- bupivacaine. Each sheep received a nerve block using the control or test formulation in each forelimb. The nerve block was placed at the level of the accessory digits with three injections totalling 4 mL using a 22G needle. The efficacy was tested by manually applying a mechanical noxious stimulus with a blunt instrument below the level of the block. This test was performed first after 15 min and then at one-hour intervals. The time at which a response was observed was considered as the end-point for that formulation. In the in vitro pilot study, both collagen and Intralipid®-based formulations showed slightly more sustained release compared to the control group. However, collagen-based formulation of bupivacaine had the most sustained-release among all. In the sheep study, the Intralipid®-based formulation significantly extended the duration of the nerve block compared to the control group (P<0.05). On the contrary, the collagen-based formulation of bupivacaine shortened the duration of action significantly compared to control group (P<0.05). In conclusion, an Intralipid®-based formulation provided a more sustained action after nerve blocks in the sheep metacarpal region compared to aqueous bupivacaine or the collagen based formulation. Further research on structure and activity of collagen and its interactions with bupivacaine is required to develop a longer acting formulation.en_US
dc.identifier.urihttp://hdl.handle.net/10179/12484
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectLocal anestheticsen_US
dc.subjectAnimal anesthesiaen_US
dc.subjectSheepen_US
dc.subjectEffect of drugs onen_US
dc.subjectResearch Subject Categories::VETERINARY MEDICINE::Other veterinary medicineen_US
dc.titleEfficacy of sustained-release novel bupivacaine formulations in sheep : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies (MVS) Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealanden_US
dc.typeThesisen_US
massey.contributor.authorSahebjam, Farzin
thesis.degree.disciplineVeterinary Studiesen_US
thesis.degree.grantorMassey Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Veterinary Studies (MVS)en_US
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