Read this article to learn about the Quality Control and Standardisation and Problems Caused by Poor Quality Unstandardized Herbal Medicines.
Quality Control and Standardisation:
Quality control involves processes that maintain the quality of a manufactured product.
A high quality herbal medicine will contain the correct plant material, or mixture of plant materials, or their extracts, exactly as stated on the product label, free from contamination with other undeclared plant materials, and free from pesticides, radioactive particles, heavy metals, microbes and mycotoxins.
This WHO publication outlines potential hazardous contaminants and residues in herbal medicines, provides general principles for assessing the safety of herbal medicines, and recommends methods for determining the level of these contaminants in plant materials.
It stresses that there is a lack of research data and that the accepted limits suggested in the guidelines are referenced and extrapolated from work carried out in the food area. Apart from ‘quality’, the other main issue in the production and use of herbal medicines is ‘standardisation’.
Until recently very few manufacturers supplied products containing standardised extracts. Standardisation is a method of assuring minimum (and maximum) level of active ingredients in the extract or the final product.
This process is becoming increasingly important, along with ‘quality control/assurance’, as a means of ensuring a consistent supply of high-quality herbal medicines.
Standardisation can be defined as the establishment of reproducible pharmaceutical quality by comparing a product with established reference substances, and by defining minimum and maximum amount of one or more compounds, or groups of compounds that are necessary in the product for efficacy and safety.
In the field of phytomedicines, standardisation may apply to the herbal raw materials, or to extracts prepared from raw materials.
Many national and international agencies have prepared pharmacopoeial monographs of the most commonly used phytomedicines, and these monographs provide information on standards of active ingredients to be used in establishing the quality of herbal medicines.
Problems Caused by Poor Quality Unstandardized Herbal Medicines:
Although herbal medicines are generally perceived by the public as ‘natural’ products, and therefore safe, there is voluminous evidence in the scientific Literature that their use is not entirely risk-free. The risk is multiplied many fold if the products marketed are of poor quality, and do not contain ‘standardised’ levels of active compounds.
The problems are further compounded by the fact that there are literally 1000s of companies world-wide offering various bands of the more commonly used herbal medicines that are of variable quality, with variable levels of the active ingredients.
As self- medication by the public with these unregulated products has increased in recent years, there has been a concomitant increase in reported adverse effects, and hospital admission attributable to use of herbal preparation.
These side-effects and other toxicities from herbal medicines occurred primarily because until recently the vast majority of such herbs and supplements had not been thoroughly investigated for safety and efficacy, and it was not appreciated that their concomitant use with other herbs or orthodox medicines would result in serious drug-drug interactions.
Drew and Mayers (1997) classify adverse effects of herbal medicines as those occurring due to:
(a) Intrinsic properties of the herb, and
(b) Extrinsic factors, such as failure of good manufacturing practice.
All drugs, whether synthetic or plant-derived, may cause toxicity if taken at inappropriate dose levels, particularly if their potential for dose related toxicity, drug-drug interaction, and idiosyncratic reaction is not carefully ascertained prior to marketing.
With herbal medicines there have been, at least in the past, problems caused by:
(a) Misidentification,
(b) Lack of standardisation,
(c) Contamination,
(d) Substitution,
(e) Deliberate adulteration,
(f) Incorrect preparation and/or dosage, and
(g) Inappropriate or incomplete labelling and/or advertising.
Thankfully the situation is improving at present, particularly because various international agencies are cooperating on the development of guidelines for the herbal industry.