Effect Of Dexamethasone Through Percutaneous Penetration On Survival Of Random Skin Flaps

Objective: The present study was designed to investigate the influence of two different chemical enhancers on dexamethasone through percutaneous penetration and to develop suitable formulations of dexamethasone gel, then to evaluate the effects of the dexamethasone gel on a rat dorsal ischemic skin flap.Methods: 0.1%, 0.3% and 0.5% of dexamethasone gels with two different enhancers containing 5%Azone and 5%diethylene glycol monoethyl ether (Transcutol), and 5%Azone+5%Transcutol were made, Skin permeation experiment was completed with a modified Franz's diffusion cell in vitro. The quantum of accumulative penetration (jug/cm~2) of dexamethasone gel across mouse, rat and porcine ear skin for 2, 4, 6, 8, 10, 24h was tested. To evaluate whether the dexamethasone gel improve skin flap survival in rats, random skin flaps were raised in 15 wistar rats. 0.1%, 0.3% dexamethasone gel (n=5) or controlled gel (n=5) wereadministered 5g/24h after flap elevation. Surviving flap areas were measured after 7 days.Result: 1. The permeability of 0.3% dexamethasone gel containing blend of 5%Azone and 5%Transcutol or 5%Azone group was higher than other groups(P<0.01). Concentrations of dexamethasone within skin in the blends of containing 5%Azone and 5%Transcutol is higher than in 5%azone (P<0.05).2. The mean surviving flap area in the 0.3% dexamethasone group was greater than that in controlled and 0.1% dexamethasone(P<0.05).Conclusion: 1 The 0.3% dexamethasone in the promoting of blends of containing 5%Azone and 5%Transcutol or 5%azone might has a satisfactory percutaneous permeability.2 Dexamethasone percutaneous penetration could improve the survival of the ischemic rat skin flaps.