ABSTRACT
Objective To develop an LC-MS/MS method for simultaneous determination of metolazone and valsartan in beagle dog plasma.Methods The chromatographic separation was achieved on an Agilent Poroshell 120(2.1 mm ×30 mm × 2.7 μm)analytical column.The multiple reaction monitoring mode operating in positive ion was adopted in MS detection, and precursors to the product ion transitions of m/z 366.2/259, 436.2/291 and 423.4/207 were used to measure metola-zone, valsartan and internal standard ( losartan potassium) .Results The method was linear over the concentration range of 0.5 ng/ml-100 ng/ml for metolazone and 5-5000 ng/ml for valsartan, with the correlation coefficients ( r2 ) of 0.9937 and 0.9939, respectively.The average intra-day precision values ( RSD) were 2.09% -8.85% for metolazone and 2.36%-13.12%for valsartan.The matrix effect values were 87.73%-98.62%for metolazone and 99.03%-137.35%for valsartan.The average recovery was 75.74%-81.82%for metolazone and 83.89%-95.64%for valsartan.Conclu-sion This analytical method for metolazone and valsartan is simple, accurate and sensitive, so it can be used for pharma-cokinetic research of metolazone and valsartan immediate release tablets in beagle dogs.
ABSTRACT
Objective To establish and validate a LC-MS/MS method for quantitative analysis of a new anti-stroke compound TID-101 in rat plasma and to study the pharmacokinetics and bioavailability of TID-101 self-(micro)emulsified drug delivery system (SMEDDS). Methods The plasma samples were treated with methanol for precipitating protein. The chromatographic separation was achieved with a acetonitrile-water mobile phase. Detection of TID-101 and the internal standard (IS) dexamethasone acetate was achieved by electrospray ionization(ESI)source in the negative ion mode at m/z 353.4→323.2 and m/z 433.4→353.4. The method was applied for pharmacokinetics study of TID-101 between SMEDDS in rats. Results The method was linear over TID-101 concen?tration range from 10-95 000 ng/ml with the correlation coefficients(r)of 0.9998. The intra-run and inter-run relative standard devia?tions(RSD)were less than 15%and the average absolute recovery values were 83.4-87.0%. The validated method was applied to a pharmacokinetic study in rats after intravenous administration of TID-101 fat emulsion injection and oral administration of TID-101 suspension and SMEDDS. The bioavailability of TID-101 API and SMEDDS was 2.8% and 14.9%,respectively. Conclusion The analysis method is simple,accurate,and sensitive for assaying the in vivo pharmacokinetic study of TID-101 in rats. SMEDDS could effectively enhance the oral bioavailability of TID-101.