Serum levels of dimenhydrinate. Determination by HPLC with UV detection after intake of dimenhydrinate in a coated chewing gum dragee.

HPLC with UV detection allowed to separate dimenhydrinate and three major metabolites (diphenyl-methoxy-ethylamine, diphenyl-methoxy-acetic acid, diphenyl-methoxy-N-methyl-amine) in human serum without extraction procedure. Detection limit was 25 ng per 500 microliter injected sample, the recovery ranged from 70 to 95%. Serum levels of dimenhydrinate were measured in healthy volunteers 15, 30, 60 and 120 min after intake of two commercially available preparations, one of them a dimenhydrinate tablet, the other one a dimenhydrinate containing coated chewing gum dragee (Travel-Gum dragee). The rise of the serum concentration of dimenhydrinate up to 30 min was smaller after intake of the coated chewing gum preparation than after swallowing the tablet. The serum concentrations at 1 or 2 h after the intake of either a tablet or the chewing gum were comparable. The variability of the serum concentrations was considerable with both preparations and seemed to be influenced more by individual factors than by previous food intake.