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Objective The metabolites of tolvaptan in rats were identified by ultra-performance liquid chromatography-quadrupole-exactive orbitrap high-resolution mass spectrometry(UFLC-Q-Exactive Orbitrap MS),and the possible metabolic pathways of tolvaptan in rats were discussed.Methods Plasma,urine and fecal samples from rats were collected after a single oral administration of 60 mg·kg-1 tolvaptan solid dispersion solution.The protein in the samples was precipitated with acetonitrile.UFLC-Q-exactive orbitrap MS technology was adopted for the sample analysis and the data were processed by Xcalibur 2.0 software.Results According to the retention time,precise relative molecular mass,characteristic fragment ions and related literature reports of each compound,35 metabolites were identified in rat biological samples.Moreover,23,26 and 30 metabolites in the plasma,urine and feces were identified,respectively.The major metabolic pathways of tolvaptan were identified as hydroxylation,carboxylation,hydrolysis,dehydrogenation,glucuronidation and acetylation.Conclusion Our study confirmed the major metabolites of tolvaptan in rats,enriched the metabolite spectrum of tolvaptan in vivo,and provided an experimental basis for the in-depth study of the pharmacodynamic substance basis of tolvaptan.
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Objective To develop an accurate,rapid and sensitive flow cytometry method for the determination of anti-mesenchymal stem cell antibody in cynomolgus monkey serum.Methods After the solutions of mesenchymal stem cell were centrifuged and washed,and the suspension was taken,positive controls or actual samples were added and incubated with mesenchymal stem cell,then were incubated with protein L-PE solution.After the removal of the free protein L-PE,the mean fluorescence intensity of the PE was detected by flow cytometry.Results The method sensitivity is 115.54 ng·mL-1,far higher than the non-clinical research recommended sensitivity of 250-500 ng·mL-1.The precision of intra-assay and inter-assay were less than 20%.Assay cut points,low positive control concentration determination,sensitivity,precision and stability were validated in this study.Conclusion The method is proved to be sensitive,specific,rapid and suitable for the determination of anti-mesenchymal stem cell antibody in monkey serum and immunogenicity study.
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A simple and sensitive liquid chromatographic method was developed for quantification of cefotetan disodium (CTT), a semi-synthetic cephamycin antibiotic, in human plasma. CTT and the internal standard chloramphenicol were extracted from plasma by a simple one-step protein precipitation with 35% (v/v) perchloric acid. Separation was carried out on a reverse-phase C18 column with a mobile phase of acetonitile-water containing 0.5% (v/v) phosphoric acids (20:80, v/v) at a flow rate of 1.0 mL/min. The column effluent was monitored by UV detection at 300 nm. The column temperature was maintained at 40°C. This method demonstrated good linearity in the range of 0.525-300.0 μg/mL, with correlation coefficients greater than 0.99. The limit of quantification (LOQ) was 0.525 μg/mL in human plasma. Intra- and inter-day precisions were less than 6.63% in terms of relative standard deviation (RSD). The accuracy, when expressed by the bias, ranged from 0.57% to 4.04%. The mean extraction recovery of CTT was higher than 40.94%. The method was found to be precise, accurate, and specific for CTT quantitative analysis, and was successfully applied for a pharmacokinetic study of CTT after a single intravenous dose of 1.0 g of CTT in healthy Chinese subjects.
Subject(s)
Humans , Cefotetan , Blood , Pharmacokinetics , Chromatography, Liquid , MethodsABSTRACT
A simple and sensitive liquid chromatographic method was developed for quantification of cefotetan disodium (CTT), a semi-synthetic cephamycin antibiotic, in human plasma. CTT and the internal standard chloramphenicol were extracted from plasma by a simple one-step protein precipitation with 35% (v/v) perchloric acid. Separation was carried out on a reverse-phase C18 column with a mobile phase of acetonitile-water containing 0.5% (v/v) phosphoric acids (20:80, v/v) at a flow rate of 1.0 mL/min. The column effluent was monitored by UV detection at 300 nm. The column temperature was maintained at 40°C. This method demonstrated good linearity in the range of 0.525-300.0 μg/mL, with correlation coefficients greater than 0.99. The limit of quantification (LOQ) was 0.525 μg/mL in human plasma. Intra- and inter-day precisions were less than 6.63% in terms of relative standard deviation (RSD). The accuracy, when expressed by the bias, ranged from 0.57% to 4.04%. The mean extraction recovery of CTT was higher than 40.94%. The method was found to be precise, accurate, and specific for CTT quantitative analysis, and was successfully applied for a pharmacokinetic study of CTT after a single intravenous dose of 1.0 g of CTT in healthy Chinese subjects.
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To investigate the disposition and tissue distribution of ML12 after intravenous (iv) administration in rats, the compound in plasma or in tissue was extracted into ethyl acetate under basic condition and was determined by HPLC after extracted by dilute sulfuric acid. Excitation wavelength and emission wavelength of fluorescence detection were 278 nm and 307 nm, respectively. The data were processed with the software 3P97 to calculate the main pharmaceutical parameters of ML12. At dose of 5 and 10 mg/kg, the elimination of the drug from plasma was found to be kinetically linear, but when the dosage was 20 mg/kg, a non-linear feature was observed. The highest level of ML12 was found in the kidney. Distribution of ML12 after iv administration was extensive and the concentration-time profile was found to be fitted to an open two-compartment model.
Subject(s)
Antihypertensive Agents/pharmacokinetics , Biological Availability , Chromatography, High Pressure Liquid/methods , Kinetics , Pharmaceutical Preparations , Rats, Sprague-Dawley , Spectrometry, Fluorescence/methods , Sulfuric Acids/chemistry , Tissue DistributionABSTRACT
OBJECTIVE:To study the pharmacokinetics of hydrochlorothiazide and valsartan in healthy volunteers after single administration of its compound dispersible tablets.METHODS:Plasma concentrations of hydrochlorothiazide and valsartan were determined by HPLC and their pharmacokinetic parameters were calculated with DAS software.RESULTS:The pharmacokinetic parameters of hydrochlorothiazide at low,medium and high doses were as follows:t1/2 were(12.56?3.66),(11.47?5.47) and(11.20?5.03) h,respectively;Cmax were(72.00?19.68),(169.96?52.17) and(203.66?61.41)ng ?mL-1,respectively;AUC0～48 were(592.87?179.44),(1 155.45?252.03) and(1 410.99?331.82) ng?h?mL-1,respectively;AUC0～∞ were(779.76?201.42),(1 246.89?307.03) and(1 482.14?332.20) ng?h?mL-1,respectively.The pharmacokinetic parameters of valsartan at low,medium and high doses were as follows:t1/2 were(7.29?3.10),(8.56?2.22) and(8.62?2.86)h,respectively;Cmax were(2.12?0.65),(6.76?2.08) and(6.71?2.59)ng ?mL-1,respectively;AUC0～48 were(18.16?4.52),(41.77?10.86) and(51.77?27.45) ng?h?mL-1,respectively;AUC0～∞ were(19.07?5.56),(42.60?11.18) and(53.49?26.93) ng?h?mL-1 respectively.CONCLUSION:The pharmacokinetics for compound valsartan dispersible tablet fitted linear kinetics process.There is no interaction in pharmacokinetics between hydrochlorothiazide and valsartan when they used in combination.