Dapsone in saliva and plasma of man

Concentrations of dapsone (DDS) and its metabolite, monoacetyl dapsone (MADDS) were measured in plasma and saliva samples collected concurrently from volunteers receiving a 50-mg oral dose of DDS. A liquid chromatographic technique was employed to separate the compounds from each other and from endogenous materials. Fluorescence detection provided limited sensitivities to 0.1 ng/ml of sample. Saliva levels of DDS were consistently 15-20% of the plasma levels of DDS during the study period, which ranged from 4 to 48 h. Decay rates for DDS from saliva and plasma were nearly identical. In 4-hour samples of plasma subjected to equilibrium dialysis, we found amounts of DDS in the dialysates nearly identical to levels found in saliva collected at that time. Saliva levels of MADDS ranged from 0.8 to 2.6% of their plasma levels at all times. Decay rates of MADDS from the two fluids were nearly identical and saliva levels of MADDS in 4-hour samples were nearly identical to levels found in paired plasma dialysates. Nevertheless, levels of MADDS were so low that a reliable definition of the subjects' acetylator phenotype from levels of MADDS in saliva only was impossible.