Herbal drugs: Standards and regulation

Abstract

The use of herbal drugs for the prevention and treatment of various health ailments has been in practice from time immemorial. Generally it is believed that the risk associated with herbal drugs is very less, but reports on serious reactions are indicating to the need for development of effective marker systems for isolation and identification of the individual components. Standards for herbal drugs are being developed worldwide but as yet there is no common consensus as to how these should be adopted. Standardization, stability and quality control for herbal drugs are feasible, but difficult to accomplish. Further, the regulation of these drugs is not uniform across countries. There are variations in the methods used across medicine systems and countries in achieving stability and quality control. The present study attempts to identify the evolution of technical standards in manufacturing and the regulatory guideline development for commercialization of herbal drugs.

Introduction

The use of plants, parts of plants and isolated phytochemicals for the prevention and treatment of various health ailments has been in practice from time immemorial. It is estimated that about 25% of the drugs prescribed worldwide are derived from plants and 121 such active compounds are in use. Of the total 252 drugs in WHO's essential medicine list, 11% is exclusively of plant origin [1]. Nearly 80% of African and Asian population depends on traditional medicines for their primary healthcare [2]. In India, about 80% of the rural population uses medicinal herbs or indigenous systems of medicine [3]. About 960 plant species are used by the Indian herbal industry of which 178 are of high volume exceeding 100 metric tonnes a year [4]. Indian herbal market is registering a significant growth and is likely to reach Rs 145,000 million by 2012 and exports to Rs 90,000 million with a CAGR of 20% and 25% respectively (ASSOCHAM, 2008).

Based on nature of the active metabolites herbal drugs are of three types. Drugs used in crude form are the first category. The active constituents isolated after the processing of plant extracts represent the second category of herbal drugs. These are pure molecules and generally pharmacologically more active. The third type of herbal drugs for which data on acute and chronic toxicity studies in animals is available [5].

In 2003, a classification system for herbal drugs was recommended in the regional workshop on the regulation of the herbal medicines, organized by WHO regional office for South East Asia. Herbal drugs have been broadly categorized into four groups such as indigenous herbal medicines, herbal medicines in systems, modified herbal medicines and imported products with an herbal medicine base [6]. Indigenous herbal medicines are well known in terms of their composition, treatment and dosage due to their age old use in a local community. Herbal medicines in systems (Ayurveda, Unani and Siddha) have been in use for a long time and therefore, for local use assessments of efficacy are not required. Modified herbal medicines represent modification of the form of indigenous herbal medicine or herbal medicine in systems either in shape or dosage form, mode of administration, herbal medicinal ingredients, methods of preparation and medical indications. These should meet the national regulatory requirements of safety and efficacy. Pre-clinical data and clinical data may or may not be required depending on the modification(s). Imported herbal medicines (that include raw materials and products) must be registered and marketed in the countries of origin. Safety and efficacy data have to be submitted to the national authority of the importing country. Good manufacturing practices (GMP) compliance of the last two categories of herbal drugs is more critical. Apart from standardized herbal extract and raw material India is known to export herbal medicines in system such as ayurvedic drugs to different parts of the world. While there is increased usage of herbal drugs throughout the world, reports on side effects and adulteration of herbal drugs have raised concerns on their wide use and are affecting their commercialization. Further, regulatory procedures of these drugs are also not uniform across different countries. The present study attempts to identify development of technical standards in herbal drug manufacturing as well as the regulatory framework for commercialization of these drugs.