SECRETION OF PROPRANOLOL ENANTIOMERS IN HUMAN SALIVA - EVIDENCE FOR ACTIVE-TRANSPORT

To study the possible transport routes which may lead to the presence of a drug in saliva, the concentration-time curves of the separate ena ntiomers of propranolol were measured in human saliva and plasma after oral administration of 10 mg of propranolol hydrochloride. Saliva sam ples were taken with the Salivette(R) device. Plasma and saliva concen trations of the enantiomers of propranolol were determined by HPLC wit h fluorescence detection. The transport of propranolol from plasma to the salivary gland appears to be not stereospecific and not saturable. Therefore, there is no indication that the transport of propranolol t o the salivary gland is active. The concentrations of both enantiomers of propranolol in saliva, however, were higher than those of both ena ntiomers in venous plasma. In the past this phenomenon was interpreted as an indication of active transport, but it could be explained by th e fact that salivary concentration more closely reflects the central c ompartment than that of peripheral venous blood.