Qualitative and quantitative assessment of related substances for ketoconazole cream based on national drug sampling...

Establishing an analytical method for the detection of related substances in ketoconazole cream is essential for improving product quality standards and ensuring the safety of this formulation.

In the 2024 National Drug Sampling Specification, we developed a novel high-sensitivity high-performance liquid chromatography (HPLC) method that effectively separates six known impurities, four preservatives, and one antioxidant present in ketoconazole creams. These creams were sourced from random market sampling and exhibited variations in prescription composition across 14 different manufacturers. Subsequently, we conducted the extraction, isolation, and characterization of common unknown impurities from these creams using mass spectrometry (MS), nuclear magnetic resonance spectroscopy (NMR), and infrared (IR) techniques. Furthermore, the structural analysis of unknown impurities within a specific enterprise was performed using high-resolution mass spectrometry and specialized software.

The established method has been thoroughly validated, demonstrating its specificity, accuracy, sensitivity, and excellent repeatability, thereby confirming its suitability for determining related substances in ketoconazole creams from various manufacturers. This method allowed for both quantitative and qualitative evaluations of impurity content across different manufacturers, identifying sulfonated impurities in ketoconazole creams for the first time and analyzing their formation mechanisms. Furthermore, strategies to reduce these impurities were proposed through correlation analysis and process validation. Additionally, this study innovatively introduced a solvent smoothing agent to mitigate solvent effects, thereby preventing the degradation of the active pharmaceutical ingredient (API) during the heating and dissolution process of the cream matrix. This technique is applicable to the pretreatment of various cream-related substance determinations.

This method provides substantial reference value for establishing analytical methods for related substances in Ketoconazole cream and offers technical support for regulatory agencies in evaluating the quality of Ketoconazole cream.