Phytosterols are a group of steroids alcohols which had been regarded as a functional factor. An unknown compound in phytosterol samples and phytosterol standard samples was detected by HPLC using symmetry C18 column....Phytosterols are a group of steroids alcohols which had been regarded as a functional factor. An unknown compound in phytosterol samples and phytosterol standard samples was detected by HPLC using symmetry C18 column. The quan- tity of the compound was increased with the enrichment of β-sitosterol. After being collected and analyzed by GC-MS and compared with standard diagram from Wiley and Nist standard chart library, it proved to be γ-sitosterol, a 24β epimer of β-sitosterol.展开更多
A simple and sensitive reverse phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of glimepiride in rat serum. The assay involves one step liquid-liquid extraction with m...A simple and sensitive reverse phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of glimepiride in rat serum. The assay involves one step liquid-liquid extraction with methanol. Gliclazide was used as an internal standard. Chromatographic separation was performed on a C18 column using a mobile phase of methanol: 10mM phosphate buffer (80:20 v/v) adjusted to pH 3.0 with orthophosphoric acid, at a flow rate of 1.0 ml/min and UV detection at 230 nm. The retention time of glimepiride and gliclazide was found to be 5.5 and 4.0 min and separation was complete in less than 10 min. The method was validated for linearity, accuracy and precision were found to be acceptable over the range of 0.5 - 500 μg/mL for glimepiride. The method was found suitable to analyse rat serum samples for application in pharmacokinetic, pharmacodynamic, bioavailability/bioequivalence studies.展开更多
Related substances in pharmaceutical formulations are associated with their safety, efficacy and stability. However, there is no overall study already published on the assessment of related substances in the Compound ...Related substances in pharmaceutical formulations are associated with their safety, efficacy and stability. However, there is no overall study already published on the assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream. In this work, a reliable HPLC-TOF-MS qualitative method was developed for the analysis of related substances in this preparation with a quick and easy extraction procedure. Besides the active pharmaceutical ingredients, two compounds named ketoconazole impurity B′ optical isomer and ketoconazole impurity E were identified. Furthermore, a new HPLC method for qualitative and quantitative assessment on related substances and degradation products, which were found in the stability test, was established and validated. The single standard to determine multi-components method was applied in the quantitative analysis, which was an effective way for reducing cost and improving accuracy. This study can provide a creative idea for routine analysis of quality control of the Compound Ketoconazole and Clobetasol Propionate Cream.展开更多
文摘Phytosterols are a group of steroids alcohols which had been regarded as a functional factor. An unknown compound in phytosterol samples and phytosterol standard samples was detected by HPLC using symmetry C18 column. The quan- tity of the compound was increased with the enrichment of β-sitosterol. After being collected and analyzed by GC-MS and compared with standard diagram from Wiley and Nist standard chart library, it proved to be γ-sitosterol, a 24β epimer of β-sitosterol.
文摘A simple and sensitive reverse phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of glimepiride in rat serum. The assay involves one step liquid-liquid extraction with methanol. Gliclazide was used as an internal standard. Chromatographic separation was performed on a C18 column using a mobile phase of methanol: 10mM phosphate buffer (80:20 v/v) adjusted to pH 3.0 with orthophosphoric acid, at a flow rate of 1.0 ml/min and UV detection at 230 nm. The retention time of glimepiride and gliclazide was found to be 5.5 and 4.0 min and separation was complete in less than 10 min. The method was validated for linearity, accuracy and precision were found to be acceptable over the range of 0.5 - 500 μg/mL for glimepiride. The method was found suitable to analyse rat serum samples for application in pharmacokinetic, pharmacodynamic, bioavailability/bioequivalence studies.
文摘Related substances in pharmaceutical formulations are associated with their safety, efficacy and stability. However, there is no overall study already published on the assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream. In this work, a reliable HPLC-TOF-MS qualitative method was developed for the analysis of related substances in this preparation with a quick and easy extraction procedure. Besides the active pharmaceutical ingredients, two compounds named ketoconazole impurity B′ optical isomer and ketoconazole impurity E were identified. Furthermore, a new HPLC method for qualitative and quantitative assessment on related substances and degradation products, which were found in the stability test, was established and validated. The single standard to determine multi-components method was applied in the quantitative analysis, which was an effective way for reducing cost and improving accuracy. This study can provide a creative idea for routine analysis of quality control of the Compound Ketoconazole and Clobetasol Propionate Cream.
