title: High-performance liquid chromatographic assay for the determination of sulfadoxine and N-acetyl sulfadoxine in plasma from patients infected with sensitive and resistant Plasmodium falciparum malaria.
abstract: A reversed-phase high-performance liquid chromatographic method using a mobile phase of acetonitrile-methanol-trifluoroacetic acid-water (16.1:7.2:0.1:76.6, v/v/v/v) at a flow rate of 1.0 ml min(-1) on a LiChrospher RP-18 column with UV (254 nm) detection has been developed for the separation of sulfadoxine and its metabolite N-acetyl sulfadoxine in plasma. No interferences due to endogenous compounds or common antimalarial drugs were noticed. The limit of detection for sulfadoxine and N-acetyl sulfadoxine was 0.01 microg ml(-1) with a signal-to-noise ratio of 5:1 while the limit of quantification was 2.5 microg ml(-1). Intra-day mean relative standard deviations (RSD's) for sulfadoxine and N-acetyl sulfadoxine were 2.6 and 2.8%, respectively, while mean inter-day RSD's for sulfadoxine and N-acetyl sulfadoxine were 2.4 and 2.8%, respectively. Extraction recoveries averaged 90.6% for sulfadoxine and 86.9% for N-acetyl sulfadoxine. The method was applied for the assay of sulfadoxine and its metabolite N-acetyl sulfadoxine in plasma from Plasmodium falciparum malaria patients. Mean plasma sulfadoxine concentrations on day 2 (51 h) from samples collected from sensitive and resistant P. falciparum patients treated with three tablets of Fansidar were 62.8 and 60.5 microg ml(-1), respectively. Mean ratio of N-acetyl sulfadoxine to sulfadoxine was 9.1% for responders and 13.9% for non-responders which revealed that higher amounts of the metabolite N-acetyl sulfadoxine were present in non-responders. The method described should find an application in the therapeutic monitoring of malaria patients.
authors.affiliation: National Institute of Malaria Research, Field Unit, Sector-III, BHEL, Hardwar 249403, India. virendradua@hotmail.com
authors.forename: Virendra K
authors.initials: VK
authors.lastname: Dua
authors.forename: N C
authors.initials: NC
authors.lastname: Gupta
authors.forename: Prerana
authors.initials: P
authors.lastname: Sethi
authors.forename: G
authors.initials: G
authors.lastname: Edwards
authors.forename: A P
authors.initials: AP
authors.lastname: Dash
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000097:blood* / Q000494:pharmacology / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016778:Malaria, Falciparum / Q000097:blood* / Q000188:drug therapy; D010963:Plasmodium falciparum / Q000187:drug effects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013413:Sulfadoxine / Q000097:blood* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000962:Antimalarials; D013413:Sulfadoxine