The Flux of Select NSAIDs through Silicone Membranes from Mineral Oil

Here we report the experimental log maximum fluxes of n = 9 non-steroidal anti-inflammatory drugs (NSAID) through silicone membranes from the lipid mineral oil (experimental (Exp.) log J(MPMO)) and correlate those Exp. log J(MPMO) values with their experimental log maximum fluxes through human skin in vivo from mineral oil (Exp. log J(MHMO)). The correlation was only fair (r(2) = 0.647) for n = 9 but improved dramatically if Nabumetone was removed from the correlation (n = 8, r(2) = 0.858). Non-linear regression of the n = 8 Exp. log J(MPMO) values as the dependent variable against their log solubilities in mineral oil (log S(MO)) and in pH 7.4 or 1.0 buffers (log S(7.4) or S(1.0), respectively), and their molecular weights as independent variables in the Roberts–Sloan (RS) equation gave a new set of coefficients for the independent variables in RS. Those coefficients have been used to calculate log J(MPMO) values which have been correlated with the Exp. log J(MPMO) values to give r(2) = 0.911 if log S(7.4) and r(2) = 0.896 if log S(1.0) were used as aqueous phases. Thus, silicone membranes appear to be good surrogates for predicting flux through human skin if the vehicle is a lipid such as mineral oil.