Abstract
The analytical method of clindamycin (CLDM) in plasma, bile and urine by high-performance liquid chromatography (HPLC) was investigated. The samples were 0.2 ml of plasma and bile, and 0.1 ml of urine containing a known amount of CLDM. Haloperidol as an internal standard (0.2 ml of 5μg/ml in methanol for plasma and bile, 0.1 ml of 30μg/ml in methanol for urine), and then 0.5 ml of 1 N sodium hydroxide and 1 ml of diethyl ether were added to each sample. The solution was shaken for 10 min and centrifuged for 10 min at 10, 000g. The organic phase was transferred to a test tube and evaporated to dryness under a stream of nitrogen gas at 50°C. The residue was redissolved in methanol (0.1 ml for plasma and bile, 0.25 ml for urine), and then 25μl of the solution was injected into HPLC. The analytical condition was as follows: the column was Nucleosil 5C18 (15cm×4, 6mm I.D.), the mobile phase was 10 mM phosphate buffer (pH 3.0)-acetonitrile (64/36, v/v), the flow rate was 1 ml/min, the column temperature was 50±0.2°C and the wavelength was 210 nm. In the concentration ranges of 0-l00μg/ml (plasma, bile) and 0-500μg/ml (urine), each calibration curve showed a good linear correlation (r=0.999). The coefficient of variationss of within-day and between-day of plasma, bile and urine samples were below 3 and 4%, respectively. The recovery was 94-106%. The present method was found to be applicable for pharmacokinetic study of CLDM in plasma, bile and urine obtained from patients.
