Determination of Plasma Concentration of Caffeine,Dapsone and Chlorzoxazone by Solid Phase Extrac-tion-HPLC and Pharmacokinetic Study / 中国药房

ABSTRACT

OBJECTIVE:To determine plasma concentration of caffeine,dapsone and chlorzoxazone in rats,and to calculate pharmacokinetic parameters. METHODS:6 rats were given the mixture of caffeine,dapsone and chlorzoxazone intragastrically, 1.5,2 and 3 mg/kg,respectively. 0.2-0.3 ml blood were collected before medication and 0.5,1,2,3,4,6,8,12,24 h after medication.The plasma sample was treated with solid phase extraction. The plasma concentration of caffeine,dapsone and chlorzoxa-zone were determined by HPLC using N-(2-Hydroxyethyl) phthalimide as internal standard. The pharmacokinetic parameters were calculated using DAS 2.0 software. RESULTS:The linear ranges of caffeine,dapsone and chlorzoxazone were all 0.2-30 μg/ml (r were 0.996 4,0.996 1,0.998 8,respectively). The limit of quantitation were 0.2 μg/ml. The recoveries of low-concentration, medium-concentration and high concentration were(84.8±3.6)%-(111.4±10.2)%(RSD were 4.3%-9.8%,n=3),(107.0±13.3)%-(113.5±8.1)%(RSD were 7.1%-14.0%,n=3),(104.2±10.8)%-(111.1±12.2)%(RSD were 8.0%-11.0%,n=3). Pharmacoki-netic parameters were as follows as tmax(1.70±0.99),(1.50±1.00),(1.92±0.80)h;t1/2(0.73±0.22),(2.77±1.35),(2.78±2.34) h;cmax (2.60 ± 0.50),(5.78 ± 1.19),(9.76 ± 1.37) mg/L;AUC0-t (8.43 ± 0.79),(20.68 ± 1.91),(26.71 ± 2.45) mg·h/L(n=6). CONCLUSIONS:The method is simple,sensitive and accurate,and can be used for the plasma concentration determination and pharmacokinetic study of caffeine,dapson and chlorzoxazone.