A sensitive and selective method has been developed and validated for the quantitation of paclitaxel in human plasma by liquid chromatography-electrospray ionization mass spectrometry （LC-ESI-MS）. Paclitaxel and norethindrone （used as internal standard, I.S.） were extracted from human plasma by a one-step liquid-liquid extraction with t-butyl methyl ether. Separation on a Zorbax SB-C18 column （100 mm×2.1 mm, 3.5 μm, Agilent） was achieved by gradient elution with methanol and 0.2 mmol/L ammonium formate containing 0.1% formic acid. The selected-ion monitoring （SIM） targeted ions of [M＋Na] at m/z 876.5 for paclitaxel and [M＋H] at m/z 299.4 for I.S. The assay was validated in the range of 1.0-400 ng/mL （r〉0.998） with LLOQ of 1.0 ng/mL. Intra- and inter-day precisions were all less than 9.0%, with accuracies of ＋6.8%. The method was successfully applied to evaluate the pharmacokinetics of paclitaxel liposome for injection in patients.
Aim To develop a method for the determination of three drug components： clonidine hydrochloride, hydrochlorothiazide and rutin in Zhenju Jiangya tablet. Methods An uncoated capillary tube was used to analyze under 20 kV voltage at 20 ℃. The samples were introduced into the capillary tube by hydrodynamic mode applying 50 kPa for 5 s and detected at 210 nm. Results The linear ranges of clonidine hydrochlofide, hydrochlorothiazide, and rutin were 10 μg· mL^-1 - 100μg· mL^-1, 30μg· mL^-1 - 300 μg· mL^- 1, and 30μg · mL^-1 - 300μg · mL^-1, respectively. Inter-day and intra-day RSD were all below 10.5%. The recoveries were 94.96% for clonidine hydrochloride, 84.45% for hydroehlorothiazide, and 89.88 % for rutin. Conclusion Clonidine hydrochloride, hydrochlorothiazide, and rutin are baseline separated. The method is simple and rapid for simultaneous determination of the three drug components in Zhenju Jiangya tablet.
