title: Rapid and simultaneous determination of sulfamethoxazole and trimethoprim in human plasma by high-performance liquid chromatography.
abstract: A simple and reproducible high-performance liquid chromatographic method was developed for simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in human plasma. The method entailed injection of the samples after deproteination with perchloric acid and subsequent neutralizing. Primidone was used as internal standard. Chromatography was performed on a C(18) column (250 mm x 4.6 mm, 5 microm) under isocratic elution with 50 mM aqueous sodium dihydrogen phosphate-acetonitrile-triethylamine (100:25:0.5, v/v), pH 5.9. Detection was made at 240 nm and analyses were run at a flow-rate of 1.5 ml/min at a temperature of 35 degrees C. The recovery was 83.4, 88.5 and 98.2% for TMP, SMX and internal standard, respectively. The precision of the method was 2.6-9.8% over the concentration range of 0.125-2 microg/ml for TMP and 0.39-50 microg/ml for SMX. The limit of quantification (LOQ) in plasma was 0.125 and 0.39 microg/ml for TMP and SMX, respectively. The method was used for a bioequivalence study.
authors.affiliation: Department of Pharmacology, Neuroscience Research Center, Shaheed Beheshti Medical University, Tehran, Iran. hamini@sbmu.ac.ir
authors.forename: Hossein
authors.initials: H
authors.lastname: Amini
authors.forename: Abolhassan
authors.initials: A
authors.lastname: Ahmadiani
mesh_terms: D000890:Anti-Infective Agents / Q000097:blood* / Q000493:pharmacokinetics; D019540:Area Under Curve; D001682:Biological Availability; D001798:Blood Proteins / Q000737:chemistry; D002138:Calibration; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D006207:Half-Life; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D012015:Reference Standards; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013810:Therapeutic Equivalency; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D000890:Anti-Infective Agents; D001798:Blood Proteins; D007202:Indicators and Reagents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination