Introduction Erdosteine [ N-（ carboxymethylthioacetyl ）-homocysteine thiolactone ] （ Fig. 1 ） is a synthetic derivative of natural amino acid methionine. It has been commonly used in clinical practice as a mucoly...Introduction Erdosteine [ N-（ carboxymethylthioacetyl ）-homocysteine thiolactone ] （ Fig. 1 ） is a synthetic derivative of natural amino acid methionine. It has been commonly used in clinical practice as a mucolytic drug and as an enhancer of respiratory ventilation in the treatment of patients with chronic obstructive respiratory disease. Erdosteine contains 2 blocked sulfhydryl groups, which are released after metabolic transformation in the liver. The liberated sulfhydryl groups break the disulphide bonds, which hold the glycoprotein fibres of mucus together; this makes the bronchial secretions more fluid and allows more rapid elimination. The reducing potential of these sulfhydryl groups accounts for the free radical scavenging and antioxidant properties of erdosteine.展开更多
A rapid and sensitive liquid chromatography-tandem mass spectrometry method（LC-MS/MS）was developed and validated for the quantification of fexofenadine in human plasma,to conduct comparative bioavailability studies....A rapid and sensitive liquid chromatography-tandem mass spectrometry method（LC-MS/MS）was developed and validated for the quantification of fexofenadine in human plasma,to conduct comparative bioavailability studies.Human plasma was extracted with a mixture of dichloromethane-diethyl ether（volume ratio 2∶3）in a basic environment and the extract was separated on a C18 column with a mobile phase consisting of acetonitrile-methanol-10 mmol/L ammonium acetate（volume ratio 45∶45∶10）.The analytes were detected via electrospray ionization（ESI）tandem mass spectrometry in the multiple-reaction-monitoring（MRM）mode.The linearity was within a range of 1-1000 ng/mL.The intra-and inter-day precision were〈4.1% and〈4.8%,respectively,and the accuracy was in the range of 95.0%-105%.The method was applied to the quantification of fexofenadine human plasma from 20 healthy male Chinese volunteers,according to a single dose,randomized,two-way crossover design with a two-week washout period.The mean values of major pharmacokinetic parameters of ρmax,AUC0-48,AUC0-∞,tmax,and t1/2 were determined from the plasma concentration.The analysis of variance（ANOVA）did not show any significant difference between the two products of fexofenadine and 90% confidence intervals fell within the acceptable range for bioequivalence.展开更多
基金Supported by the National Nature Science Foundation of China(No.39930180).
文摘Introduction Erdosteine [ N-（ carboxymethylthioacetyl ）-homocysteine thiolactone ] （ Fig. 1 ） is a synthetic derivative of natural amino acid methionine. It has been commonly used in clinical practice as a mucolytic drug and as an enhancer of respiratory ventilation in the treatment of patients with chronic obstructive respiratory disease. Erdosteine contains 2 blocked sulfhydryl groups, which are released after metabolic transformation in the liver. The liberated sulfhydryl groups break the disulphide bonds, which hold the glycoprotein fibres of mucus together; this makes the bronchial secretions more fluid and allows more rapid elimination. The reducing potential of these sulfhydryl groups accounts for the free radical scavenging and antioxidant properties of erdosteine.
文摘A rapid and sensitive liquid chromatography-tandem mass spectrometry method（LC-MS/MS）was developed and validated for the quantification of fexofenadine in human plasma,to conduct comparative bioavailability studies.Human plasma was extracted with a mixture of dichloromethane-diethyl ether（volume ratio 2∶3）in a basic environment and the extract was separated on a C18 column with a mobile phase consisting of acetonitrile-methanol-10 mmol/L ammonium acetate（volume ratio 45∶45∶10）.The analytes were detected via electrospray ionization（ESI）tandem mass spectrometry in the multiple-reaction-monitoring（MRM）mode.The linearity was within a range of 1-1000 ng/mL.The intra-and inter-day precision were〈4.1% and〈4.8%,respectively,and the accuracy was in the range of 95.0%-105%.The method was applied to the quantification of fexofenadine human plasma from 20 healthy male Chinese volunteers,according to a single dose,randomized,two-way crossover design with a two-week washout period.The mean values of major pharmacokinetic parameters of ρmax,AUC0-48,AUC0-∞,tmax,and t1/2 were determined from the plasma concentration.The analysis of variance（ANOVA）did not show any significant difference between the two products of fexofenadine and 90% confidence intervals fell within the acceptable range for bioequivalence.
