title: High performance liquid chromatography for quantification of gatifloxacin in rat plasma following automated on-line solid phase extraction.
abstract: An automated system using on-line solid phase extraction and HPLC with fluorimetric detection was developed and validated for quantification of gatifloxacin in rat plasma. The extraction was carried out using C(18) cartridges (BondElut), with a high extraction yield. After washing, gatifloxacin was eluted from the cartridge with mobile phase onto a C(18) HPLC column. The mobile phase consisted of a mixture of phosphoric acid (2.5mM), methanol, acetonitrile and triethylamine (64.8:15:20:0.2, v/v/v/v, apparent pH(app.) 2.8). All samples and standard solutions were chromatographed at 28 degrees C. The method developed was selective and linear for drug concentrations ranging between 20 and 600 ng/ml. Gatifloxacin recovery ranged from 95.6 to 99.7%, and the limit of quantification was 20 ng/ml. The intra and inter-assay accuracy were up to 94.3%. The precision determined not exceed 5.8% of the CV. High extraction yield up to 95% was obtained. Drug stability in plasma was shown in freezer at -20 degrees C up to 1 month, after three freeze-thaw cycles and for 24h in the autosampler after processing. The assay has been successfully applied to measure gatifloxacin plasma concentrations in pharmacokinetic study in rats.
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga, 2752, Porto Alegre, RS 90.610-000, Brazil. leandrotasso@hotmail.com
authors.forename: Leandro
authors.initials: L
authors.lastname: Tasso
authors.forename: Teresa
authors.initials: T
authors.lastname: Dalla Costa
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D019540:Area Under Curve; D001322:Autoanalysis; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D004355:Drug Stability; D005470:Fluorometry; D024841:Fluoroquinolones / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D005615:Freezing; D000077734:Gatifloxacin; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D008297:Male; D015394:Molecular Structure; D009862:Online Systems; D051381:Rats; D017208:Rats, Wistar; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D013696:Temperature; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D000077734:Gatifloxacin