According to World Health Organization (WHO), herbal medicines can be defined as plant-derived materials or products with therapeutic and other human health benefits. It contains raw or processed ingredients that are obtained from one or more plants. The herbal medicines can be classified into three categories and they are raw plant materials, processed plant materials, and also medicinal herbal products. 1
Medicinal herbal products is the finished and labelled pharmaceutical products in dosage form that contain one or more of the following components. The components can be powdered plant materials, extracts, purified extracts and partially purified active substances that are isolated from the plant materials. 2
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Nowadays, the use of herbal medicines has increased significantly as it provides a lot of benefits to the health of individuals and communities. World Health Organization (WHO) sets up a guideline to standardized the quality of herbal formulations. The guidelines are as follow:
1.Assessment of quality of crude drugs material, plant preparations and also the finished products
2.Assessment of stability and the herbal product’s shelf life
3.Assessment of safety of the herbal product and also the documentation of the safety based on the experience or toxicological studies
4.Assessment of efficacy of herbal product by using the ethnomedical information and also the evaluation of the product’s biological activity
It is always essential to ensure the safety, quality, and efficacy of herbal medicines so that the herbal medicines can show its maximal effects when it is taken by the patients. The safety, quality, and efficacy of the herbal medicines can be controlled by applying the modern techniques during the manufacturing of the herbal medicines. Besides, a set of suitable standards and Good Manufacturing Practices (GMP) should be followed to ensure the quality, safety and efficacy of drugs that are derived from the plants. 3
In order to ensure the quality, safety, and efficacy of the herbal medicines, consumers and the health care providers play a significant role. They need to constantly supply latest information on the benefit and adverse effect of the herbal medicines.
World Health Organization (WHO) sets up a guideline for assessment of herbal medicines. These guidelines plays a key role to ensure the safety, efficacy, and quality of herbal medicines. The objectives of the guidelines are as follow:
1.Define the basic criteria for the assessment of the quality, safety and quality of herbal medicines
2.Assist the national regulatory authorities, scientific organizations and manufacturer to carry out an evaluation of the documentation or submission in respect of such products 3
The traditional experience, medical, historical as well as the ethnological background of the herbal medicines should be considered in the assessment or evaluation of the herbal medicines. This is a general rule in the assessment of the herbal medicines. The traditional experience means the long-term use. The long-term use can be defined differently in different country but they should be at least last for several decades.
The description in the medical, pharmaceutical literature or similar sources should be taken into account in the assessment. The documentation of knowledge on the application of a herbal medicine also need to be considered in the assessment or evaluation of herbal medicines.
Long-term and apparently uneventful use of a substances or product will provide a testimony of its safety. The substances that are obtained naturally and used as the ingredients in the preparation should be investigated for its potential toxicity. The regulatory authorities need to respond immediately if the substances show a previously unsuspected potential for systemic toxicity, carcinogenicity and teratogenicity. The regulatory authorities can withdraw the license of the registered products that containing the suspected ingredients. They can also reschedule the substances to reduce their use to medical prescription. 3
2.ASSESSMENT OF QUALITY
The pharmaceutical assessment or evaluation of the herbal medicines should include all the important aspects of the quality assessment of herbal medicines. The pharmaceutical assessment should be capable to make reference to a existing pharmacopoeia monograph. If there is no such pharmacopoeia monograph, a monograph need to be supplied and such monograph should be set out as in an official pharmacopoeia.4
The procedures that involve in the manufacturing of herbal medicines need to be carried out according to the Good Manufacturing Practices (GMP).
The crude drug materials of plant origin can be standardized by using the following steps:
?Authentication. This involves the stage of collection, parts of the plant that need to be collected like flowers, leaves, roots, barks, stems, roots and barks, regional status, microscopical and histological analysis, taxonomical identity and lastly the botanical identity.
?Foreign matter. The herbs that are collected need to be free from impurities from soil and atmosphere, for example, insects, animal excreta and others.
?Organoleptic evaluation. This is based on the morphological features of the crude drug materials. The shape, size, taste, odour and feeling of the crude drug materials need to be evaluated.
?Tissues of diagnostic importance that can be found in the powder of the crude drugs.
?Ash values and extractive values. Ash indicates the residue remaining after incineration. It also represents the inorganic salts that are naturally occurring in the drug or adhere to it or deliberately added as a form of adulteration. It can be divided into two forms which are total ash and acid insoluble ash. Total ash consists of carbonates, phosphates, silicates and silica. The acid insoluble ash is part of the total ash and it is insoluble in dilute hydrochloric acid. Extractive value indicates the extracts obtained by exhausting crude drugs. It represents the approximate measure of their chemical constituents. 5
?Volatile matter present in the crude drug materials.
?Determination of the moisture content of the crude drug materials. The percentage of the active constituents of the crude drugs is mentioned on air-dried basis. The moisture content of the crude drug need to be minimized to prevent the decomposition.
?Chromatographic and spectroscopic evaluation. Thin layer chromatography (TLC), high performance thin layer chromatography HPTLC), and high performance layer chromatography (HPLC) can provide both the semi-quantitative and qualitative information of the active constituents of the crude drug materials. Chromatgraphic fingerprint can be used to identify the quality of the herbal medicine.
?Heavy metals like the arsenic, lead and cadmium can be determined.
?The pesticide residue need to be controlled. World Health Organization (WHO) and also the Food and Agricultural Organization (FAO) set the limits for the use of pesticides in planting the herbs. During the cultivation, the pesticides will mix with the herbs. DDT, BHC, aldrin and toxaphene are the common pesticides that have been used nowadays and they can cause severe harmful effects to the human being. 6
?Microbial contamination. The crude drug materials should be free from the microorganism from the soil and also the atmosphere.
?Radioactive contamination. Irradiation can definitely prevent the microbial growth in the herbs as this process will sterilize the plants. But, this process will leave the radioactivity hazard to the plants. So, the radioactivity of the plants have to be checked in accordance with the guidelines of International Atomic Energy in Vienna and World Health Organization (WHO).
2.1CRUDE PLANT MATERIAL
The family, genus and species of the plant should be provided in order to identify the plant correctly. The part of the plant like flower, bark, stem, leaves, wood, root, or fruit where the medicine can be obtained need to be given as well. It is also important to specify whether the fresh, dried or traditionally processed material is used in the manufacturing of medicines.
The active constituents of the medicine need to be identified and their amounts need to be specified as well. Besides that, the foreign material and impurities found in the medicines should be as minimal as possible. This is very important in order to ensure the quality of the herbal medicines. 4
Moreover, the microorganisms found in the should be as minimal as possible as well. This is because the herbal medicines usually contain bacteria and mould that are obtained from the soil and atmosphere. The limits of the microbial contamination are as follow:
Limit for Microbial Contamination
Microorganism Product Raw Materials
E.coli 10¹ –
Salmonella – –
Total aerobic bacteria 10^5 –
Enterobacteria 10³ –
According to the World Health Organization (WHO), the plant preparation can be the powdered plant materials, extracts, tinctures, fatty or essential oils, expressed juices and the products where the process of fractionation, purification, and concentration are involved in their production. The procedures that are involved to prepare the herbal medicines required to describe as detail as possible to ensure the quality of the herbal medicines.
The excipients that are required to be added during the manufacturing procedure need to specified. The excipients are the substances that added to adjust the herbal products or preparations to a certain level or for any other purposes.
The assay or the way to identify the active constituents of the herbal preparations can be added if possible. The method to identify a specific or characteristic substances that are contained in the preparation need to be mentioned if the assay and the method to identify the active constituents is not available. 4
The procedure and formula used to manufacture the herbal preparations and products need to be mentioned as detailed as possible. This should include the amount of excipients and active constituents used in the preparation. The way to identify or specify the finished product should be mentioned as well. The methods that can be used to identify the active constituents of the finished product need to be specify. If it is not available, the methods that can be used to identify the characteristic substances contained in the finished product should be mentioned. This is very important in order to ensure the consistent quality of the finished herbal products.
Furthermore, the finished products of the herbal medicine need to be manufactured in accordance with the general requirements for particular dosage form. The finished herbal products that are imported from one country to others require to get the confirmation of the regulatory status from the products’ origin country. 4
It is essential to ensure the stability of the herbal medicine in order to maintain the quality of the product. The products need to be physically and chemically stable. The physical and chemical stability of the herbal preparation can be known by placing the herbal preparation in the container in which it is to be marketed under defined storage condition. By doing so, the shelf-life of the herbal products can be tested indirectly.
3.ASSESSMENT OF SAFETY
To assess or evaluate the safety of the herbal medicines, it should include all the important aspects of the safety assessment. If a product that has been used traditionally for a long period of time and it does not show any harmful effects to the human being, the products can be assumed to be safe. The immediate actions should be taken if there is any report says that the products cause harmful effects in human being. The products need to be evaluated for its safety again.
The relevant books or materials should be provided to help to evaluate the safety of the herbal products. These books or materials can act as a reference. If a recognized monograph results are available, it can also be used as a reference to assess the safety of the product.
If a herbal medicines that have been used traditionally for a long period of time and does not show any adverse effects to the consumers, it always assumes that the products are safe to be used. But, it is not certain. The harmful effects may be expressed in many years later. So, it is always essential to evaluate the safety of a products and does not harm the consumers.
The harmful effects that have been reported by the consumers need to be recorded and documented according to the normal practices. The is important to be used as a reference later. 7
Toxicological studies is part of the assessment that evaluating the safety of the herbal products. It can be used to identify the harmful pesticides, active constituents and metabolites that presence in the herbal products.
The toxicological studies use two limit values for the assessment of the safety of the products.
?Acceptable daily intake (ADI) is one of the limit value that has been used to evaluate the safety of a products. It determine whether the long-term intake of a substances will cause the harmful effects in the consumers or not. It determines the adequate amount of substances that can be taken by the consumers and does not bring any adverse effects to the human being. 6
?Acute reference dose (ARFD) is another limit value that can be used for the assessment of the safety of the herbal products. It is specifically used for the active constituents that have a high level of toxicity and might damage the health of the consumers after a single intake or a short-term intake. 6
3.2DOCUMETATION OF SAFETY BASED ON EXPERIENCE
It is a general requirement to consider the documentation of the long period of use when evaluate the safety of the herbal products. This documentation plays a key role when the toxicological studies are not available. This documentation will be used as a basis to evaluate the safety of the products. The documentation can be used only when there is no occurrence of the safety problems. However, the toxicological effects that have been occurred may be failed to identified.
The length of time, the health problems, the number of consumers and the countries need to be described in detailed in a report. These data or report have to be submitted to be used as a reference.
The health disorders that are occurred whether dependent to the dose or independent to the dose need to be noted down and submitted. For the health problems that are dependent on the dose, the dosage specification need to specified. If possible, the reasons or the explanations need to included as well. Other problems like potential for drug misuse, drug abuse and drug dependence can be included in the documentation so that they can be used as a reference later.
If the herbal products that have been used traditionally for a long time and the harmful effects are observed, they cannot be documented. The toxicity data need to be submitted in this case. 7
4.ASSESSMENT OF EFFICACY
To assess or evaluate the efficacy of the herbal products, all the important aspects of efficacy assessment should be included. The related original articles, books or other materials should be provided to be used as a reference in the assessment of the efficacy of the products. If a research studies for a particular product has been carried out, it can also be included to be used to evaluate efficacy of the herbal products.
The pharmacological, therapeutic and clinical effects of the active substances that are found in the herbal products need to be specified as detailed as possible. The constituents of the active ingredient should be described as well. 8
4.2EVIDENCE REQUIRED TO SUPPORT INDICATIONS
The indications for the use of the herbal medicines need to be specified and described in detailed. The indication of the medicines that are used traditionally require the proof of their efficacy. This requirement is depend on the type of the indication that have been suggested. For the medicines that are used to treat the minor disease and for the indications that are not specific, there will be some relaxation in requirements for proof of efficacy. The extent of the traditional use will be taken into account to evaluate the efficacy of the herbal products.
The medicines that have been used for the prophylactic purposes also need the proof of their efficacy. The individual health reports that are prepared or written by the physicians, health professionals, traditional health practitioners or the treated patients can be included and to be used to evaluate the efficacy of the products.
If the medicines are not use traditionally, a standard or recognized clinical evidence should be provided to be used for the assessment. 8
Most of the herbal products that are available or can be found in the market will contain more than one type of active constituents. These products are known as combination products as they contain a combination of several active constituents. Besides, based on the experience, the combination products are frequently used as the traditional remedies.
To assess or evaluate the efficacy of the herbal products, the old and new combination products need to be distinguished. This is because there are different requirements used by both of the old and new combination products to evaluate their efficacy. If same procedures are used to assess both the combination products, inaccurate results will be obtained.
In case of the combination products that are used traditionally, evidence like the documentation and also the experience of the traditional use can be used. The classical texts of Ayurveda and traditional Chinese medicine are the example of the documentation.
Furthermore, in case of the new combination products, the effective dosage of the drug, drug compatibility and drug interaction need to explain as detailed as possible. The ingredients that are combined to form the combination product need to be specified as well. In addition, traditional knowledge of the active ingredients also need to be included. The active ingredients that contain in the herbal product should be efficient to treat the disorders.
If the clinical studies have been carried out for a particular ingredients, the studies can be included to evaluate the efficacy of the herbal products. 8
The intended use of a product indicates whether the products is used accordingly based on the information that have been given by the manufacturer or supplier on the labeling. The intended use of a product is regulated by the Food and Drug Administration (FDA) under the Federal Food, Drug, and Cosmetic Act.
The label on the herbal product plays a main role as it ensures the users or consumers to take the drug correctly and does not cause any unintended effects. The effects of the herbal medicine will be shown if the drug is taken correctly according to the instructions.
The labels on the package inserts should be clearly understandable by the consumers or users. The selection of the language and words is very important. Simple language and words should be used so that it can be easily understand by patients and not cause any misunderstanding or confusion. 9
All the necessary information should be included in the labels that are attached on the products. The necessary information are as follow:
?Name of the product
?List of the active ingredients and the amount of each ingredient
– dosage that is required for children and adult
-mode of administration
-duration of use
-major adverse effects that might be occurred
-immediate action that need to be taken if overdosage
-contraindication, warnings, precaution and major drug interactions
-use of the drug during pregnancy and lactation
?Manufacture date and expiry date
?Registration or license number
?Name and address of the manufacturer
The active ingredients of the herbal product can be written in both of the Latin botanical name and also the common name in the language that is preferred by one’s country. Sometimes, not all the necessary information will be available in one label. 9
Example of the label on the herbal product.
5.1PROMOTION AND ADVERTISEMENT
The advertisements and the promotional activities that have been done in the public should be totally similar to the product information that have been accepted by the regulatory authorities.
Immediate actions should be taken by the regulatory authorities if the particular company of a product was against the law. 9
5.2MONITORING OF ADVERSE REACTIONS
A system use to monitor the harmful effects or adverse reactions of a herbal medicines should be set up by the regulatory authorities. Besides, the users, manufactures and the patients are encouraged to report to the regulatory authorities if they encounter any adverse reactions after consuming the products.
Immediate actions like the investigation should be taken by the regulatory authorities. If toxic substances have been found in the herbal product, warnings should be given to the public. They should also restrict the use of the herbal medicine.
The records of the adverse effects of the herbal medicine need to document so that it can be used as a reference later.
The guidelines that have been set up by the World Health Organization (WHO) will ease the burden of regulatory authorities, scientific organization, and manufacturer in the assessment of the quality, safety and efficacy of the herbal medicines.
The assessment that has been done by them is important to be used in the future for the basis of the classification of herbal medicines. This is very useful as it can be used all over the world. 10
Close co-operation with the nationwide institutions is essential to keep all the aspects of manufacturing and use of the herbal medicines under standard regulation. Close liaison with the countrywide institution is important to carry out the clinical or evaluative studies of the quality, efficacy, and safety of the herbal products.