Chitosan microspheres with hydrocortisone and hydrocortisone-hydroxypropyl-β-cyclodextrin inclusion complex

In the present study, an inclusion complex composed of hydrocortisone acetate (HC) and hydroxypropyl-beta-cyclodextrin (HP beta CD) was prepared by the spray-drying method. HC alone, HC inclusion complex or HC with HP beta CD as a physical mixture were incorporated into chitosan microspheres by spray-drying. The inclusion complex and microspheres were characterized by X-ray powder diffractometry and differential scanning calorimetry (DSC). Microspheres were studied with respect to particle size distribution, drug content and in vitro drug release. The results indicate that the HCHP beta CD inclusion complex is more water soluble than HC alone. The HC release rates from chitosan microspheres were influenced by the drug/polymer ratio in the manner that an increase in the release rate was observed when the drug loading was decreased. However, release data from all samples showed significant improvement of the dissolution rate for HC, with 25-40% of the drug being released in the first hour compared with about 5% for pure HC. The complexation method and microsphere preparation method (spray-drying) is simple with great potential for industrial production. (C) 2000 Elsevier Science B.V. All rights reserved.