Intra-individual and inter-individual variation in breath alcohol pharmacokinetics: Variation over three visits

•18 student subjects underwent serial Breath Alcohol Concentration measurements.•Considerable intra- & inter-individual variation existed in C0, Cmax, Tmax and Elimination rate.•Widmark factors were calculated by various established mathematical methods.•Elimination rates in males and females were not significantly different.

Eleven male and 7 female student subjects underwent serial Breath Alcohol Concentration (BrAC) measurements after being given alcohol as 13% white wine (5.7 ml/kg for males and 4.7 ml/kg for females) in a fasting state on three separate occasions. BrAC versus time curves were constructed for each subject and the values of peak BrAC (Cmax), theoretical BrAC extrapolated at zero time (Co), time taken to reach peak (Tmax) and rate of elimination (ß) from breath were recorded directly from the curves. Average Intra-individual variation for each individual between the 3 visits (for males and females, respectively) was 5.6% and 8% for Co, 12% and 13% for Cmax, 42% and 37% for Tmax and 11% and 13% for ß. Inter-individual variation (for males and females) was 7.5% and 13% for Co, 16% and 15% for Cmax, 43% and 46% for Tmax and 21% and 15% for ß. Average elimination rates in males (5.3 μg/100 ml breath/h, range 4–7.7) and females (5.6 μg/100 ml breath/h, range 4–7) were not significantly different. Widmark factors calculated by various established mathematical methods were 0.71–0.81 in males and 0.59–0.68 in females, higher than the originally quoted mean experimental levels.