A simple and sensitive high-performance liquid chromatographic method to measure antipyrine and its metabolites in human urine

A method which permits the simultaneous HPLC analysis of antipyrine (A), 3-hydroxymethylantipyrine (HMA), 4-hydroxyantipyrine (HOA) and norantiopyrine (NORA) using a single extraction step in a five minute chromatographic run is described. Only 500 micraLitro of urine were necessary for the quantitation of all compounds investigated. An analog derivative, 4-aminoantipyrine, was used as internal standard (IS). Urine samples were hydrolyzed with Limpet acetone powder, 37 graus centigrados, pH 5.0 for 2 h. Sodium chloride was added and urine samples were extracted with diclhormethane-isopropyl alcohol (90:10, v/v) in acidic medium. The residue was dissolved with mobile phase, washed with n-hexane and 20 micralitro of the lower phase were injected into a 4-micron Nova-Pak (R) 'C IND. 18' column. Peaks monitored at 254 nm were eluted with 0.75 M sodium acetate buffer, pH 5.0: methanol, (70:30, v/v) as mobile phase. The method, validated on the basis of the confidence limits for antipyrine and its metabolites, presented good stability, sensitivity, linearity, and intra or interassay precisions lower than 5 percente for all commpounds were investigated. This assay was applied for drug metabolism study carried out in ten healthy volunteers: 23 about 5 yr and 63 about 10 kg(mean about SD) after p.o. single dose of antipyrine, 500 mg/capsule. Diuresis of 24 h up to 72 h of drug administration was preserved with sodium metabisulfite, 4 mg/mL. Biological fluids were stored at -20 centigrade degree until assay. The main hydroxy-metabolites (HMA + HOA) and NORA, minor N-demethylated metabolite of antipyrine, were excreted: 60 percent and 20 percente as percentage of the given dose, respectively. Clearances for production of metabolites expressed as mL/min, were: 8.61 about 4.28 (7.24) for HMA, 13.91 about 6.20(12.67) for HOA, and 8.08 about 4.01(5.93) for NORA, mean about SD (median).

Antipyrine clearance and metabolite excretion in Saudi patients with non-alcoholic chronic liver disease

In this report, we examined the hepatic microsomal enzyme activity in 34 Saudi patients with chronic liver disease [CLD] and in 21 healthy Saudi subjects by measuring antipyrine clearance [APC1] and the fraction [%] of antipyrine [AP] dose excreted in urine unchanged [F[Ap] and in the form of its main metabolites: 3-hydroxymethylantipyrine [F[HMAp]] norantipyrine [F[NORAP] and 4-hydroxyantipyrine [F[4OHAP]]- While APC1, F[HMAP] F[NORAP] and F[4OHAP] were significantly reduced in patients with CLD, F[AP] was significantly higher in these patients. Correlation was observed between serum albumin and APC1, F[HMAP] F[NORAP]'or F[4OHAP] and between each two of the last three variables. We conclude that Saudis with CLD have uniform rather than selective reduction of hepatic microsomal enzyme activity and that serum albumin is a sensitive indicator of this activity

Hepatic drug metabolizing capacity of patients of cirrhosis before and after clinico-biochemical recovery.

The present study was undertaken to determine whether, along with clinico-biochemical recovery there was associated restoration of hepatic drug metabolizing capacity in patients of cirrhosis after treatment of their cirrhosis, using serum antipyrine half life, the ideal index. Estimation of serum antipyrine half life before (26.34 +/- 2.4 hr) and after (18.83 +/- 2 hr) clinico-biochemical recovery showed significant (P less than 0.01) improvement in drug metabolizing capacity of liver. Biochemical parameters of liver function tests except serum total proteins and prothrombin time showed simultaneous improvement.