Population Pharmacokinetic Analysis of Alcohol Concentration after Beer Consumption in Fasted Japanese Subjects

The absorption rate of alcohol is one of the determinants of the peak blood alcohol concentration. Studies focusing on factors that cause inter-individual variability in absorption rate have not been conducted. To conduct a population pharmacokinetic analysis to identify variables that explain inter-individual differences in the absorption rate of alcohol, using blood alcohol concentrations immediately after consumption of a low dose of alcohol under fasting conditions. The study enrolled 34 healthy Japanese subjects, consisting of 21 males and 13 females (mean age, 29.4±12.9 years; mean body weight, 61.3±10.8 kg). All subjects consumed a single 350 mL can of beer (17.5 g of alcohol) after an overnight fast: an average dose of 0.232 g of alcohol per kg of body weight. A total of 157 samples were collected from 5 to 60 min after consumption of alcohol. A one-compartment model was fitted as a base model. The estimates of the population mean absorption rate and the population mean apparent volume of distribution were 0.023 1/min and 48.3 L, respectively. Age was positively correlated to the individual absorption rate and negatively correlated to the individual apparent volume of distribution, and body weight and ADH1B genotype affected the apparent volume of distribution. The key finding of this study is that age was positively correlated with alcohol absorption rate, suggesting that aging cause higher peak BAC due to higher absorption rate combined with lower apparent volume of distribution.