Influence of cyclodextrin complexation on the in vitro permeation and skinmetabolism of dexamethasone

The influence of complexation of a model drug, dexamethasone acetate (DMA), with beta-cyclodextrin (beta-CyD) and hydroxypropyl- beta-cyclodextrin (HP -beta-CyD) on the in vitro permeation through hairless mouse skin and on sk in metabolism have been investigated. Complexation with CyDs increased the amount of DMA permeated in the order of 2.0 and 3.0 times for beta-CyD and HP-beta-CyD, respectively. The partition coefficient, between stratum corne um and buffer (K-SC/buffer), for DMA decreased when the drug was an inclusi on complex, being greatest for DMA/HP-beta-CyD complex. Complexation protec ted the drug against skin metabolism. The increase of skill permeation and stability of the model drug in the skin suggest that the complexation with beta-CyD and HP-beta-CyD is a rational way to improve the physical-chemical properties of drugs for use in transdermal delivery systems. (C) 2000 Else vier Science B.V. All rights reserved.