Determination of heavy metals in traditional herbal medicines by alternative analytical techniques employing green chemistry principles

Abstract

The use of plants for medicinal purposes is widespread in the entire world. Their popularity is due to the ease of access, therapeutic effectiveness, relatively low cost and the belief that do not exhibit toxic effects. Herbal are basically divided into two classes: i) herbal medicines (HM) and herbal traditional products (HTP), evidence of safety and efficacy occurs by means of clinical studies for HM, and for HTP occurs by time of use based on technical-scientific literature. Without the need for medical prescription, HTP consumption occurs in the empirical way, based on self-medication, and in many cases without any information about the product origin. Poisonings reported in the literature associated with the presence of lead, mercury, arsenic and cadmium show the need for rigorous quality control analysis for HTP. However, the pharmacopoeial methods for heavy metal determination have been the same for more than one century, and these do not meet toxicological limits established by ICH Q3D. U.S. Pharmacopeial Convention (USP), aware of this need, has published a new chapter for metallic impurities analysis by inductively coupled plasma (ICP). Due to the high costs of acquisition and maintenance of ICPs, mainly for small manufacturers and compounding pharmacies, this project aims to develop alternative analytical methodologies using capillary electrophoresis (CE) associated with on-line pre-concentration techniques (stacking e sweeping) and off-line, employing green chemistry precepts, such as: microextraction techniques and cloud point extraction (CPE) for heavy metals determination in notified HTP marketed in Brazil. (AU)