In vitro skin penetration of propranolol enantiomers

Transfer rates of individual enantiomers of propranolol across human skin were determined in vitro. Percutaneous penetration of propranolol from propylene glycol was negligible at the concentration previously reported to show enantioselective transfer in rat skin. Transfer of (R)- and (S)-propranolol from aqueous solutions of both the racemate and the pure enantiomers showed no differences in the rates of penetration demonstrating that the rate of transfer of propranolol across human skin from these solutions was independent of the stereochemistry of the drug. In addition there was no evidence for racemisation during the transfer process.