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 qua-litative 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 ke-toconazole 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 pro-ducts, 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.

Objective To explore the relationship between hypoxia-inducible factor-1α (HIF-1α) expression and apoptosis in early brain injury models after subarachnoid hemorrhage (SAH).Methods Fifty-five adult male Sprague-Dawley rats were randomly assigned to five groups:sham-operated group,SAH 6 h,SAH 12 h,SAH 24 h and SAH 72 h groups (n=1 1).SAH in the later four groups was induced by modified monofilament puncture method.The rats were killed by cervical dislocation.HIF-1α expression was assessed by immunofluorescence staining.TUNEL was adopted to detect brain apoptotic cells.Immunofluorescence double staining was used to identify cell types with positive HIF-1α expression.Pearson correlation analysis was employed to analyze the relationship between HIF-1 expression percentage and TUNEL positive rate.Results As compared with those in the sham-operated group,the HIF-1 expression percentage and TUNEL positive rate in the four SAH groups was significantly higher (P＜0.05).Immunofluorescence double staining showed that neuron-specific nuclear protein staining cells were coincided with most HIF-1 positive cells,while only a few HIF-1α positive cells were coincided with glial fibrillary acidic protein staining cells.A significant positive correlation was noted between HIF-1 α expression percentage and TUNEL positive rate following SAH (r=0.737,P=0.001).Conclusion HIF-1α high expression after SAH early promotes neuronal cell apoptosis,indicating HIF-1 a might participate in the pathological progression of early brain injury after SAH.