Nyeki, A. published the artcileNAT2 and CYP1A2 phenotyping with caffeine: head-to-head comparison of AFMU vs. AAMU in the urine metabolite ratios, HPLC of Formula: 608-34-4, the publication is British Journal of Clinical Pharmacology (2003), 55(1), 62-67, database is CAplus and MEDLINE.
Aims. (i) To compare the phenotyping of healthy subjects for NAT2 (N-acetyltransferase) and CYP1A2 activities with caffeine, by the simultaneous assay of the urinary metabolites AFMU and AAMU, and (ii) to ascertain whether NAT2 and CYP1A2 phenotyping is influenced by the use of AFMU or AAMU in the metabolite ratio. Methods. Thirty-five healthy subjects (16 men, 19 women) participated to the study. Caffeine metabolite concentrations were measured in urine collected 8 h after 2.5 mg kg-1 caffeine intake using a new validated h.p.l.c. method. The metabolite ratios AFMU/1X, AFMU/(AFMU+1X+1U), AAMU/1X, AAMU/(AAMU+1X+1 U), and (AFMU+1U+1X)/17U, (AAMU+1U+1X)/17U were determined as indexes of NAT2 and CYP1A2 activity, resp. Results. Slow and rapid acetylators were similarly identified using the four NAT2 metabolite ratios in 139 out of 1.40 measurements. An appreciable amount of AAMU was present in urine that was immediately acidified and analyzed. Consequently, the ratio using AFMU was lower than that using total AAMU following transformation of AFMU in basic conditions. The proportion of AFMU in urine analyzed immediately expressed as AFMU/(AFMU+AAMU) ratio did not correlate with urine pH, but was a function of the acetylation phenotype, with a low intergroup variability (64±3% and 32±5%, for rapid and slow acetylators, resp.; P < 0.00001, ANOVA). Regarding CYP1A2 activity, a good correlation (r = 0.99) was observed between the metabolite ratios calculated from AFMU and AAMU, although the ratios calculated from AFMU were proportionately and systematically lower (P < 0.00001, paired t-test, slope 1.2). Conclusions. This study demonstrates that both AFMU and AAMU can be used for NAT2 and CYP1A2 metabolite ratio determinations The reported conversion of AFMU into AAMU is unlikely to explain the large amount of AAMU in urine that was acidified and analyzed immediately after voiding. The results suggest that AAMU is formed not solely through a nonenzymic hydrolysis in urine, but in vivo by a NAT2 phenotype-dependent pathway.
British Journal of Clinical Pharmacology published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, HPLC of Formula: 608-34-4.
Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia