Effect of Arachis and Eucalyptus Oils on Insulin Release from Transdermal Patches

Study intended to demonstrate the effects of arachis and eucalyptus oils as release modifiers in insulin transdermal patches. Patches were prepared by solvent casting technique using hydroxypropyl methlycellulose solution as the aqueous phase and polysorbate 80 as emulsifying agent. Various batches (TD1-TD5) were prepared using varying proportions of the oils and aqueous phases and then subjected to physical evaluations such as; weight variation, thickness, percentage moisture sorption and content, drug content, bioadhesion and folding endurance. In vitro release studies was carried out using the USP paddle method prescribed for transdermal patches. Ex vivo permeation and in vivo release studies were also carried out. Patches containing eucalyptus oil showed highest percentage moisture sorption of 775%, while those containing arachis oil gave highest percentage moisture content of 77.8%. There was increase in the in vitro release of insulin with increasing concentrations of the oils with patches containing arachis oil giving a higher release than the eucalyptus oil patches. Ex vivo diffusion through treated rat skin gave similar diffusion rates as in the in vitro release. In vivo results obtained showed significant percentage blood glucose lowering activity with TD1 (36%) and TD3 (23%) after 6h of patch administration as against the intraperitoneally administered insulin (control) which gave 82% glucose lowering after 1h. Arachis and eucalyptus oil improved and sustained the in vitro and in vivo release of insulin from transdermal insulin patches with arachis oil at 20% showing the greatest improvement.