[Studies on purine-pyrimidine metabolism (1)--Quantitation of purine-pyrimidine metabolites and allopurinol-oxipurinol in biological fluids].

A reversed-phase high-performance liquid-chromatography method for determining simultaneous quantitation of purine-pyrimidine metabolites, allopurinol and oxipurinol in plasma and urine samples was studied. Separation was optimal with phosphate buffer (10 mmol/l, pH 5.0) containing 1% methanol as an eluent and mu Bondapak C18 as a column. An isocratic separation of a standard mixture of 13 compounds was achieved within 40 minutes with adequate reproducibilities (coefficient of variation: 2.49% for 1.63 mumol/l orotidin-0.12% for 50 mumol/l uridine). A simple ultrafiltration of plasma yielded quantitative recoveries (uric acid: 101.7-107.5%, hypoxanthine: 90.4-102.8%, xanthine: 95.9-99.5%, oxipurinol: 104.4-107.1%, allopurinol: 97.4-103.4%). Compounds were identified by their retention times, absorbance ratios, co-elution with standards and enzymic shifts. In addition to the above compounds, simultaneous quantitation of pseudouridine, uridine, adenine and inosine in the plasma would be possible under the same conditions.