Quantitation of paclitaxel in micro-sample rat plasma by a sensitive reversed-phase HPLC assay

• Published in: Journal of pharmaceutical and biomedical analysis Vol. 31; no. 2; pp. 283 - 289
• Main Authors: Wang, L.Z, Ho, P.C, Lee, H.S, Vaddi, H.K, Chan, Y.W, Yung, Chan Sui
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 26.02.2003; Elsevier Science
• Subjects: Animals; Antineoplastic agents; Antineoplastic Agents, Phytogenic - blood; Antineoplastic Agents, Phytogenic - pharmacokinetics; Biological and medical sciences; Chromatography, High Pressure Liquid - methods; General aspects; Medical sciences; Paclitaxel; Paclitaxel - blood; Paclitaxel - pharmacokinetics; Pharmacology. Drug treatments; Rat plasma; Rats; Reproducibility of Results; Reversed-phase HPLC; Sensitivity and Specificity; Reversed-phase HPLC; Paclitaxel; Rat plasma; Solid phase extraction; Biological fluid; Rat; Rodentia; HPLC chromatography; Blood plasma; Vertebrata; Reversed phase chromatography; Mammalia; Absorption; Ultraviolet detector; Analysis method; Revcrsed-phase HPLC; Animal; Taxane derivatives; Plant origin; Pharmacokinetics; Quantitative analysis
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/S0731-7085(02)00611-8

A sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of paclitaxel in micro-samples of rat plasma in order to study the mechanism of enhanced systemic exposure of paclitaxel co-administered with P-glycoprotein inhibitors. The assay involved solid-phase extraction procedures using 2′-methylpaclitaxel as the internal standard. Chromatographic separations were achieved using a ZORBAX ODS C18 column and mobile phase consisting of acetonitrile, methanol and ammonium acetate buffer (10 mM, pH 5.0) (48.5:16.5:35) pumped at 0.8 ml/min. The effluents were measured for UV absorption at 227 nm, with retention times of 8.5 and 11.0 min for paclitaxel and 2′-methylpaclitaxel, respectively. The chromatographic separation was excellent, with no endogenous interference. The standard curves showed a good linearity ( r=0.9994) over the concentration ranges of 10–1000 ng/ml. At 1000 ng/ml, the absolute recoveries of paclitaxel and 2′-methylpaclitaxel are 89 and 90%, respectively. The intra- and inter-day variabilities of paclitaxel were both less than 15%. This validated method for the assay of paclitaxel in micro-sample rat plasma made it feasible to study the pharmacokinetics of the drug in a single rat.