ABSTRACT
Unlike most Western medicines (WM), which typically contain a single active ingredient, TCM usually contain a number of components. However, the pharmacological activities, interactions, and relative proportions of these components are usually unknown. In practice, TCM is usually prescribed subjectively by an experienced Chinese doctor. As a result, the actual dose received by each individual varies depending on the signs and symptoms as perceived by the Chinese doctor. Although the purpose of this medical practice is to reduce the within-subject (or intrasubject) variability, it could also introduce non-negligible variability such as variations from component to component and from one Chinese doctor to another. Consequently, the reproducibility or consistency of clinical results is questionable. Thus, how to ensure the reproducibility or consistency of the observed clinical results has become a concern to regulatory agencies in the review and approval process (e.g., DOH 2004a,b; FDA 2004). In addition, it is also a great concern to the sponsor in the post-approval manufacturing process for assuring consistency of raw materials, in-process materials, and final products.
