Saliva Levels as an Index of the Pharmacokinetics of Chloroquine.
The saliva levels of chloroquine in nine subjects after a single 600mg oral dose of the drug and in one subject after a single 200mg i.m. dose were investigated for 21 days. The presence of chloroquine and the major metabolite, desethylchloroquine, in saliva was established by chromatographic and spectroscopic methods. Chloroquine concentrations were determined by a sensitive ion-pair reversed-phase h.p.l.c. method. It was found that chloroquine was secreted into human saliva throughout the period of sampling. The results showed that chloroquine is rapidly absorbed with the time of peak concentration in saliva (tmax ) of 4.1 + 1.6 hr, A long elimination half-life of 7-20 days calculated from the saliva concentration-time profile is in agreement with the same values previously reported for the drug using plasma level data In three of the subjects, from whom simultaneous blood samples were collected, a weak but significant correlation between saliva and total plasma levels was observed (r = 0.68, P .< 0.01). The mean ratio of the saliva to plasma concentration (S/P) was 1.20 + 0.27. It is suggested that saliva level determination may be used for the evaluation of pharmacokinetic parameters and therapeutic monitoring of chloroquine in man.