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 compare the imaging characteristics and surgical methods of pulmonary nodules in the external 1/3 group and internal 2/3 group. Methods A retrospective analysis of clinical data from patients who underwent thoracoscopic preoperative CT-guided lung nodule localization at the Department of Radiology, the First Affiliated Hospital of Xiamen University from September 2020 to April 2022 was conducted. Results A total of 215 patients were enrolled (247 pulmonary nodules), including 70 males and 145 females, with a median age of 48 years. Based on the location of the nodules under CT guidance, those located in the external 1/3 area of the lung were classified into an external 1/3 group, while those located in the middle 1/3 and inner 1/3 areas were classified into an internal 2/3 group. There was no statistical difference between the two groups in terms of general clinical data, nature of pulmonary nodules, distribution of pulmonary nodules in lobes, localization time, or localization complications (P>0.05). However, there were statistical differences in the distance of pulmonary nodules from the pleura [0.6 (0.0-1.9) cm vs. 1.8 (0.0-4.5) cm, P<0.001], size of pulmonary nodules [0.7 (0.2-1.8) cm vs. 1.0 (0.2-2.0) cm, P<0.001], and surgical methods (P=0.002). In the external 1/3 group, 92.1% of nodules underwent thoracoscopic wedge resection, while fewer patients underwent other procedures; in the internal 2/3 group, 77.1% of nodules underwent thoracoscopic wedge resection, and 19.3% underwent segmentectomy. Conclusion The diameter of pulmonary nodules, the distance of pulmonary nodules from the pleura, and surgical methods differ between the external 1/3 group and internal 2/3 group. Thoracic surgeons can develop more precise surgical plans based on the location and size of pulmonary nodules.