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

J Chromatogr B Biomed Sci Appl. 1997 Sep 12;697(1-2):283-8. doi: 10.1016/s0378-4347(97)00084-4.


A capillary zone electrophoresis method has been developed for the determination 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 than 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 separation of the analytes is achieved in a run time of 12 min (15 min total, including capillary wash). Using PAS as a probe for N-acetyltransferase 1 activity, 20 healthy volunteers were phenotyped after oral administration of a 1 g dose. The preliminary results seem to indicate a bimodal distribution of N-acetyl-PAS/PAS molar ratios.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetamides
  • Adolescent
  • Adult
  • Aminosalicylic Acid / urine*
  • Aminosalicylic Acids / urine*
  • Arylamine N-Acetyltransferase / genetics
  • Arylamine N-Acetyltransferase / urine*
  • Electrophoresis, Capillary
  • Female
  • Humans
  • Male
  • Middle Aged
  • Phenotype
  • Salicylates / urine*


  • Acetamides
  • Aminosalicylic Acids
  • Salicylates
  • acetyl 4-aminosalicylic acid
  • 4-acetamidosalicylic acid
  • Aminosalicylic Acid
  • Arylamine N-Acetyltransferase