Studies on the release of drugs from O/W-emulsion ointments using the mathematical interpretations. Part 1: Influence of the thickness of the ointment layer.

The hyperbolic function Q = t/(A + Bt) has been applied to the quantitative description of the release process from the emulsion ointment as influenced by the thickness of the layer. Results have been compared with the analogous ones obtained by the use of Higuchi's "exponential" equations. This comparison leads to the conclusion that the proposed empirical function is especially usefull for thin ointment layers.