Pharmacokinetics of Phytopharmaceuticals: A Peek into Contingencies and Impediments in Herbal Drug Development

Abstract

Plant secondary metabolites have been extensively used in the treatment of many diseases and have served as compounds of interest, both in their natural form and as templates for synthetic modification. With the help of the traditional knowledge, indigenous people try to derive therapeutic materials from thousands of plants; however, their safety and efficacy remain a vital concern. Natural product-based drug discovery involves the identification of new chemical entities (NCEs) of potential therapeutic interest through chemical synthesis or isolation from natural sources. Although some of these drugs have entered the international pharmacopeia through the study of ethnopharmacology and traditional medicine, they are very small in number. It is because of limitations with the availability of proper guidelines for standardization, manufacture, and quality control, which are required for herbal medicinal products. Data regarding the safety and efficacy needs to be generated from preclinical and clinical pharmacokinetic and pharmacodynamic studies. A better understanding of pharmacokinetics and bioavailability of phytopharmaceuticals can be of immense help in designing the rational dosage regimens. Based on the preclinical pharmacokinetic data, suitable formulations may be developed to ensure optimum efficacy and safety. In this article, the authors would like to share their research experiences about various aspects of pharmacokinetics, which need to be addressed to generate reliable data on safety and efficacy of herbal drugs. This information would be helpful in designing rationalized preclinical pharmacokinetic studies.