Quality Control and Standardisation of Herbal Medicines

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.