Experimental study of in vitro buprenorphine hydrochloride transdermal permeation through hairless mouse skin

To investigate the in vitro transdermal permeation of buprenorphine hydrochloride gel through hairless mouse skin and the effect of permeation enhancers on the permeability of this transdermal drug delivery system.

Skin samples 1.0 cm in diameter were obtained from hairless mice for subsequent in vitro tests of the permeability of the drug. In permeation enhancer-free group, the permeability of buprenorphine hydrochloride at the concentrations of 0.5%, 1.0% and 2.0% was tested. The permeation enhancer group (all application containing 1% buprenorphine hydrochloride) was further divided into oleic group (including 3 subgroups with 2%, 4%, and 6% oleic), azone group (subdivided into 3 groups with 1%, 2%, and 4% azone) and mixed group (with 4% oleic plus 4% azone). The permeation parameters, namely steady state flux (Js) and Js enhancement ratio were evaluated.

Js in permeation enhancer-free groups were 0.69+/-0.11, 0.90+/-0.14 and 1.18+/-0.10 microgram/cm2.h respectively, which differed only insignificantly (P>0.05). The mixed group showed the maximum permeation, with Js and ER of 13.22+/-1.27 microgram/cm2.h and 14.6 respectively.

Permeation enhancers significantly increase Js of buprenorphine hydrochloride gel and renders its release kinetics approaching zero-order.