[Drinking study on the pharmacokinetics of the grappa congener 2-butanol]

A drinking study on the pharmacokinetics of the typical grappa congeners 2-butanol and 2-butanone (methyl ethyl ketone) was performed. It was expected that the concentration ratio might provide a means to estimate the time of ingestion of a grappa beverage. Twelve subjects drank a volume of the grappa "Vecchio di Prosecco" (42 vol%) to reach a blood alcohollevel of 1.20 %o. In the congener analyses in serum, a median 2-butanol concentration of 0.79 mg/1 (range 0.45-1.34 mg/1) and of 1.01 mg/I (0.44-1.62 mg/1) for 2-butanone were measured. The concentration-time curve was biphasic starting with a slow and plateau-like elimination. However, considerable inter-individual differences were observed. Only in 3 subjects, a 2-butanol : 2-butanone ratio below 1 suggested ingestion within the last 6 hours. The majority of the subjects exhibited higher concentrations of 2-butanone than of 2-butanol such that the ratio was always smaller than 1. According to the present results the concentrations of 2-butanol and 2-butanone or their ratio do not provide a reliable basis to draw conclusions on the time of grappa ingestion.