Nicoli Sara, Colombo Paolo, Santi Patrizia
Pharmacy Department, Parco Area delle Scienze 27/A, 43100 Parma, Italy.
AAPS J. 2005 Sep 2;7(1):E218-23. doi: 10.1208/aapsj070120.
The aim of this work was to investigate, in vitro, the kinetics of release and permeation of caffeine, chosen as model drug, from bioadhesive transdermal films. These films are not self-adhesive but become adhesive when applied to wet skin. Permeation experiments were performed from films with different drug loadings using rabbit ear skin as barrier. In order to characterize the release kinetics of caffeine from the film, a polyethylene membrane, impregnated with isopropyl myristate was employed. The data obtained in the present work suggest that caffeine release from transdermal bioadhesive films was controlled either by the permeability characteristics of the skin or by the film itself, depending on drug loading. When drug loading is low (ie, caffeine is dissolved in the polymers constituting the film), the control resides in the skin. When caffeine loading exceeds its solubility in the film, the permeation profile is not linear, but shows a sort of burst effect in the early times of permeation, probably owing to the presence of solid drug and/or to a certain degree of "conserved supersaturation" in the solid phase.
本研究旨在体外研究作为模型药物的咖啡因从生物黏附性透皮膜中的释放和渗透动力学。这些膜本身不具有自黏性，但应用于湿润皮肤时会具有黏性。使用兔耳皮肤作为屏障，对不同药物载量的膜进行渗透实验。为了表征咖啡因从膜中的释放动力学，采用了浸渍有肉豆蔻酸异丙酯的聚乙烯膜。本研究获得的数据表明，根据药物载量，咖啡因从透皮生物黏附膜中的释放要么受皮肤的渗透特性控制，要么受膜本身控制。当药物载量较低时（即咖啡因溶解在构成膜的聚合物中），控制因素在于皮肤。当咖啡因载量超过其在膜中的溶解度时，渗透曲线不是线性的，而是在渗透初期呈现出一种突释效应，这可能是由于存在固体药物和/或固相中有一定程度的“保守过饱和度”。
