DETERMINATION OF P-AMINOSALICYLIC ACID AND ITS N-ACETYLATED METABOLITE IN HUMAN URINE BY CAPILLARY ZONE ELECTROPHORESIS AS A MEASURE OF IN-VIVO N-ACETYLTRANSFERASE-1 ACTIVITY

A capillary zone electrophoresis method has been developed for the det ermination of p-aminosalicylic acid (PAS) and its metabolite, N-acetyl -p-aminosalicylic acid (N-acetyl-PAS), in urine. A linear relationship was observed between time-normalized peak area and the concentration of the parent and metabolite with correlation coefficients greater tha n 0.9990. The method could be applied to the determination of PAS and N-acetyl-PAS in human urine without any sample pretreatment. A good se paration of the analytes is achieved in a run time of 12 min (15 min t otal, including capillary wash). Using PAS as a probe for N-acetyltran sferase 1 activity, 20 healthy volunteers were phenotyped after oral a dministration of a 1 g dose. The preliminary results seem to indicate a bimodal distribution of N-acetyl-PAS/PAS molar ratios. (C) 1997 Else vier Science B.V.