Development, transfer and validation of a HPLC-DAD method for analysis of six herbal medicines marketed in D.R. Congo: Fingerprinting and stability study

Context: Phytomedicines, also known as improved traditional medicines (ITMs), are increasingly used in the management of diseases throughout the world. While quality control widely known to be an essential tool that can ensure the efficacy and safety of health products, most ITMs lack appropriate analytical methods for their control. The aim of this study was to develop a reliable analytical method for the quality control of ITMs commonly used in the Democratic Republic of the Congo (D.R. Congo). For this purpose the method needs to be validated and transferred. Objectives: The objective of this research was to develop, transfer, and validate an affordable, rapid and easily implementable analytical method by HPLC-DAD for the quality control of herbal medicines marketed in the Democratic Republic of the Congo. Also, to determine these drugs fingerprint and their stability under accelerated conditions. Methods: Chromatographic separation was achieved using two chromatographic columns, an XBridge C18 (250 × 4.6 mm i.d.; 5 μm particle size) and an XBridge C18 (100 × 4.6 mm i.d.; 3.5 μm particle size), column maintained at 30 °C. The mobile phase consisted of a gradient mixture of mobile phases A (acetonitrile) and B (aqueous solution of trifluoroacetic acid 0.05%) pumped at 1.0 mL/min. UV detection was performed at 280 nm. The method using the short column was validated using the total extracts as references. The strategy of total error was used to decide on the reliability of the method taking into account the acceptance limits fixed at ± 10%. Results: The validation results show that the developed HPLC-DAD method presented an adequate trueness, linearity, precision and accuracy. Two extra peaks found in the finish products did not interfere with phytomarkers, thus confirming the selectivity of the developed method as appropriate chromatographic profiles. The method was successfully used to determine the content of the phytomarkers in six ITMs. Furthermore, we could notice that the ITMs submitted to the accelerated degradation studies remained chemically stable over six months of harsh treatments. Conclusion: A generic method of analysis of herbal medicines was developed using HPLC-DAD, and subsequently validated before being applied in a stability study of these drugs. The proposed method holds the promise of providing a new tool for quality product development in the field of traditional herbal medicines