[Preparation of diazepam transdermal gel and its bioavailability].

OBJECTIVE: To prepare diazepam transdermal gel and to assess its bioavailability. METHODS: Using Carbopol 934 as a gel matrix, the diazepam transdermal gel was prepared with glycerol as the humectant and azone as penetration enhancer. The penetration rate of diazepam through excised rabbit skin was measured by Franz diffusion cell and HPLC method. Using diazepam tablets as control, the relative bioavailability of diazepam gel was determined in rabbits. RESULTS: The transdermal flux of diazepam gel was 39.26 g/cm(2)/h and the bioavailability of diazepam gel was 36.25%. CONCLUSION: Diazepam gel prepared in the study would be developed as a novel transdermal preparation.