Facile and rapid high-performance liquid chromatography method for simultaneous determination of allopurinol and oxypurinol in human serum

Abstract

This method is useful for routine therapeutic drug monitoring of allopurinol in a clinical setting.

A simple method for quantification of allopurinol and oxipurinol in human serum by high-performance liquid chromatography with UV-detection

“…Previously, it was suggested to use ammonium sulfate for precipitation instead of a strong acid solution (perchloric acid as in our method or trichloroacetic acid as described by Kramer et al [22]), because it was found that the low pH of the injected samples could shorten column life [26]. Recently, Tada et al did not find any column deterioration using acidic samples and a buffered mobile phase (100 mM potassium phosphate; pH 4.0) [14]. Using a buffered mobile phase, we injected more than 300 samples as described in the methods section.…”

“…As a consequence, gout patients often have multiple drug use. Prior research had several major limitations regarding (1) information on interference of detection and quantification of allopurinol and oxipurinol by endogenous compounds and frequently used co-medication by gout patients; (2) an upper limit of quantification of oxipurinol that did not cover the complete concentration range expected to be obtained in patient samples; (3) information about the stability of the analyte [14][15][16][17][18][19][20][21][22]. In addition, we used a washing step with dichloromethane to extract relatively hydrophobic substances, thereby reducing the amount of possible interferences and late-eluting substances (e.g.…”

“…When a more rapid method is preferred, a method might be set up with a flow of 2 mL/min, as described previously [14].…”

“…However, these published methods, using reversed phase high-performance liquid chromatography, might have several limitations [14][15][16][17][18][19][20][21][22]. For example, (1) lack of information on chromatographic interference on detection and quantification of the analytes by concomitant medications frequently used by gout patients; (2) upper limits of quantification not covering the complete concentration range as observed in clinical practice; and (3) absence of stability data of allopurinol and oxipurinol in serum kept under refrigerated conditions.…”

Simultaneous determination of 16 purine derivatives in urinary calculi by gradient reversed-phase high-performance liquid chromatography with UV detection

“…Although numerous reversed-phase chromatographic methods are used for analysis of oxypurines [11,[17][18][19][20][21], methylated purines [18,[22][23][24], 2,8-dihydroxyadenine [12,19,20], allopurinol and oxypurinol [11,[19][20][21]23,25], they are not designed to separate simultaneously all the purines specific for urinary calculi. Original double gradient of pH and methanol content in mobile phase was used, because we could not achieve satisfactory separation of all analytes with constant buffer pH.…”