title: Coupling of TLC and UV-measurement for quantification of naproxen and its main metabolite in urine.
abstract: A simple sensitive method of high specificity and selectivity for quantitative determination of the non-steroidal anti-inflammatory drug naproxen and its main metabolite, 6-demethylated derivative, in biological specimens is described. Like naproxen, its metabolite absorbs maximally at 232 nm; this makes their simultaneous quantification, via direct UV-measurements at lambda max, in biological fluids quite impossible. Simple TLC-separation on silica gel F254 using chloroform + methanol (85:15, v/v) achieved the best fractionation of the unchanged drug and its metabolite from the matrix-contents of urine. UV-quantification of fractionated components could reach concentration levels of 0.2-3.0 micrograms ml-1 (ppm) in worked up urine samples. Varying levels of unchanged antiinflammatory drug and the phenolic metabolite could be accurately traced in urine samples following a 2.9 mg/kg oral dose after different time-intervals. Synthetic preparation of the metabolite by demethylation of naproxen is briefly mentioned.
authors.affiliation: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
authors.forename: E M
authors.initials: EM
authors.lastname: Abdel-Moety
authors.forename: A M
authors.initials: AM
authors.lastname: Al-Obaid
authors.forename: A I
authors.initials: AI
authors.lastname: Jado
authors.forename: E A
authors.initials: EA
authors.lastname: Lotfi
mesh_terms: D002855:Chromatography, Thin Layer; D006801:Humans; D009288:Naproxen / Q000378:metabolism / Q000652:urine*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D009288:Naproxen