ABSTRACT
OBJECTIVE:An LC-MS method was developed for the determination of thioctic acid in human plasma.MET-HODS:The chromatographic separation was carried out on Zorbax SB C18 column with the mobile phase consisting of methanol-acetonitrile-0.1% glacial acetic acid(adjusted pH to 4.0 with ammonia)(55∶10∶35) at a flow rate of 0.3mL?min-1.Naproxen was used as internal standard.Column temperature was 40℃.SIM was used for determination of thioctic acid in human plasma.Ion mass spectral(m/z) of 205.0 was selected for thioctic acid and 229.3 for naproxen.RESULTS:The linear range of thioctic acid was 0.01～10?g?mL-1(r=0.999 9).The method recovery was within 97.61%～106.31%.The intra-day and inter-day RSD of thioctic acid(high,medium and low concentrations) were all less than 4%.CONCLUSION:The method is sensitive,accurate and reproducible,and suitable for the determination of thioctic acid in human plasma and its pharmacokinetic and bioavailability study.
ABSTRACT
OBJECTIVE:To improve the HPLC-fluorometric method in the determination of telmisartan in human plasma.METHODS:Using naproxen as internal standard,the plasma was extracted with ethyl acetate.The separation was performed on Symmetry C8 with mobile phase consisted of acetonitrile -0.01mol?L-1 potassium dihydrogen phosphate buffer solution(47∶53) at a flow rate of 1.0ml?min-1.The ?Ex was set at 305nm and the ?Em was set at 365nm,and the sample size was 20?L.RESULTS:The linear range of telmisartan was 2.5～200ng?mL-1(r=0.999 8),with the lowest detectable limit at 1ng?mL-1.The average recovery of extraction was (89.91?10.07)%.Both the intra-day RSD and inter-day RSD were less than 10%.The sample showed a good stability within 24 hours after three freeze-thaw cycles and extractions.CONCLUSI-ON:The method is simple,sensitive,accurate and reproducible,and suitable for the determination and pharmacokinetic study of telmisartan in human plasma.