title: High-performance liquid chromatographic determination of amoxicillin in urine using solid-phase, ion-pair extraction and ultraviolet detection.
abstract: A simple, robust high-performance liquid chromatographic method is described for assaying amoxicillin in urine. Sample clean-up involved solid-phase, ion-pair extraction onto Sep-Pak C18 cartridges followed by elution with acetonitrile (3%, v/v) in pH 4.85 buffer. Separations were performed on an Ultrasphere C18 column with a mobile phase comprising acetonitrile (32.5 ml) and pH 7.1 phosphate buffer (0.01 M, 1000 ml). Peaks were detected at 229 nm. Recovery was greater than 94%. Plots of peak area against urinary amoxicillin concentration were linear (r > 0.999) from 5 to 500 mg/l. Between-day and within-day imprecision (coefficient of variation) ranged between 3.0 and 15.5%. Inaccuracy was 7.1%, or less.
authors.affiliation: Department of Pharmacy, University of Queensland, Brisbane, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Chulavatnatol
authors.forename: B G
authors.initials: BG
authors.lastname: Charles
mesh_terms: D000658:Amoxicillin / Q000493:pharmacokinetics / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D012015:Reference Standards; D013056:Spectrophotometry, Ultraviolet
chemical_list: D007202:Indicators and Reagents; D000658:Amoxicillin