Abstract:Objective : To screen the formulations of cryptotanshinone gel for treatment of topical diseases such as acne. Method : Different cryptotanshinone gels incorporating various penetration enhancers at different concentrations were prepared using carbopol 934L as matrix. The steady transdermal fluxes and drug retention amounts in skin of the gels were investigated on single chamber diffusion cells using excised rat abdomen skin as model and 40% polyethylene glycol-400 saline as releasing media. The optimal formulation would be the gel which had the maximum drug retention amount/ transdermal drug flux ratio. Result : The promotion effects of menthol at different concentrations were as follows: 5％＞3％＞1％, and the effects on drug retention amount in skin were followed as: 5%≈3%＞1%; The promotion effects of azone at different concentrations were as follows: 5％≈3％＞1％, and the effects on drug retention amount in skin were as follows: 5%＞3％≈1％. Combination of enhancers showed no superior effects compared to single uses. 5% azone had the maximum retention amount/ transdermal flux ratio. Conclusion : The optimal formulation was the cryptotanshinone gel containing 5% azone.