[Phenotyping of cytochrome P-450 1A2 and N-acetyltransferase (NAT2) using the in vivo caffeine test as a tool for determining individual susceptibility to selected xenobiotics].

An in vivo phenotyping method of CYP1A2 (cytochrome P-450 1A2) and NAT2 (N-acetyltransferase, isoform 2) based on caffeine test (Butler et al. Pharmacogenetics 1992;2:116-127) with modifications has been established. Molar concentrations of caffeine and its metabolites in urine were determined by HPLC with gradient elution and spectral detection (200-350 nm). The results obtained with this method were sufficiently accurate and precise and allowed to calculate the respective parameters which were subsequently used to evaluate the CYP1A2 and NAT2 activities.