Miconazole-loaded 6-oxychitin-chitosan microcapsules

Oxychitin-chitosan microcapsules were prepared and assayed for the purpose of delivering miconazole. The microcapsules formed upon contacting 4% oxychitin solution with 2% chitosan solution, both containing 1-2% calcium chloride. The encapsulation efficiency for miconazole was 49-67%. The drug-loaded microcapsules (1-2 mm diameter) were spherical, translucent and stable over the observation period of 7 days in the wet state. The microcapsules disintegrated in the presence of sodium dodecyl sulfate at pH 7.1 and the delivery of miconazole was delayed compared to control. The microcapsules were also degraded by lysozyme that, however, was partially inhibited by the oxychitin-rich fragments released by the external layer as well as by the oxychitin entrapped in the core. Oxychitin was also found to be biocompatible towards human keratinocytes that normally grew in the presence of uronans added to the culture medium. It is concluded that the polyelectrolyte complex formed by oxychitin and chitosan is safe and suitable for the preparation of microcapsules, whose performances depend on the selection of the preparation conditions. Oxychitin offers the advantage of depressing the hydrolytic action of lysozyme on the chitosan present in the complex, thus retarding the drug release. (C) 2002 Elsevier Science Ltd. All rights reserved.