A RAPID AND SENSITIVE HPLC METHOD FOR THE ANALYSIS OF PROGUNAIL AND CYCLOGUANIL IN PLASMA: APPLICATION TO SINGLE DOSE PHARMACOKINETIC STUDIES

Abstract

A simple, sensitive cost-effective and reproducible reverse phase high performance liquidchromatographic (HPLC) method was developed to quantitate plasma levels of proguanil(PGN) and its active metabolite, cycloguanil (CGN) in order to conduct single dosepharmacokinetic studies. The drug and the internal standard were added to plasma samples,vortexed and rendered alkaline with 2 M NaoH and the samples extracted with ether,evaporated to dryness and the residue was reconstituted in methanol, whirlmixed beforeinjecting an aliquot onto the HPLC system. The calibration plots were linear over theconcentration range up to 4.0 μg /ml. The correlation coefficients (r) were of the order of 0.99and above for both PGN and CGN. The ion pair method was carried out on a 5 μ reversephase C-18 column, using perchlorate ion as the counter ion and ultra violet detection at 254nm. The method was reproducible with coefficient of variation for PGN and CGN, being lessthan 4.0 %. PGN was well resolved from its active metabolite, CGN, and the internalstandard, pyrimethamine. The limit of detection of PGN was 10 ng /ml and the recovery wasgreater than 95% in plasma. The analytical method therefore, exhibits good precision andsensitivity in detecting and quantifying PGN and CGN and has been demonstrated to besuitable for the pharmacokinetic studies of proguanil. The clinical applicability of the methodwas assessed by the preliminary pharmacokinetic study of PGN and CGN, in fifteen healthyvolunteers. The in vivo study was carried out according to a single dose randomized design