Validation of standardized high-performance thin-layer chromatographic methods for quality control and stability testing of herbals

In herbal medicinal products the entire herbal drug or an herbal drug preparation is regarded as the active pharmaceutical ingredient, regardless of whether constituents with defined therapeutic activity are known. In quality control and stability testing of herbal medicinal products, fingerprint chromatograms are used as powerful tools to evaluate and compare the composition of compounds in such products. To fulfill the International Conference on Harmonization and Good Manufacturing Practice-based regulatory requirements in pharmaceutical quality control, chromatographic fingerprint analysis needs to be validated. Based on a standardized methodology, this paper provides a comprehensive concept for evaluating validation parameters for planar chromatographic fingerprinting by considering the stationary phase, sample application, developing solvent, chromatogram development, plate labeling, derivatization, documentation, and chromatographic equipment. Validation parameters addressed include stability of the analyte, selectivity, robustness testing, and method reproducibility.