OBJECTIVES: To optimize the formulation of diethylamine salicylate gel by comparative study on transdermal osmotic rate.METHODS: 3 diethylamine salicylate gels were prepared using 2 propanol as osmotic enhancer in different concentration and Fanz diffusion cells were adopted in the transdermal osmotic test of isolated mouse skin. RESULTS: The transdermal osmotic process fitted to a zero order kinetic mechanism. The osmotic enhencer effect of 2 propanol was listed below: 15%> 10%>5%. CONCLUSIONS: The me...