[Determination of drug availability from commercial topical formulations with a multilayer membrane model].

Using the multilayer membrane system (MMS) the drug availability of four drugs from commercial topical formulations are determined. It was found that the availability differs when commercial formulations of beta-methasone-17-valerate, hydrocortisone, diclofenac-Na and clotrimazole were studied. It is shown that the drug availability for characterizing topical formulations has to be taken into account. The MMS applied in this study can be used for the determination of this parameter.