Herbal Formulary And Formulations

Feature Article Herbal Formulary And Formulations
JAN 21, 2017 LISTEN

Health delivery is not complete without the prescription of medicines and adherence of patients/clients to the prescribed medicines. In Ghana, most herbal centers/clinics started as manufacturers of herbal medicines, making available various herbal medicinal products to the general public through herbal shops and pharmacies till date.

Products like the TONICS are manufactured to provide a general wellbeing by toning the body tissues and improving blood circulation. Some herbal medicines/products are meant to offer relief to certain symptoms experienced at any point in time whiles others are specific to one or more disease conditions. Herbal medicines exist in the form of herbs, herbal materials, herbal preparations and finished herbal products.

Herbs and herbal materials are well utilized by practitioners in herbal clinical settings for the benefits of patients than with peddlers on buses, street, etc, whiles the latter may be directly made available on the market through the appropriate outlets. The influx of herbal products recently is a response to the technological change of the 21st century. Product forms such as capsules, syrups, powders, ointments, creams, soap, among others, are produced using processes outlined in standard books like the British Pharmacopoeia, Pharmaceutical compounding books, as well as the Herbal Pharmacopoeias. An example of these standards is the development of a good product formulary/formula prior to production.

Product formulas comprises of two main components’; active constituents and excipients. Active constituents are responsible for therapeutic actions to alleviate symptoms, and treat/manage disease conditions. Active constituents in pharmaceuticals/orthodox medicines are purified isolated chemicals included singly or combined in different formulas specified for different conditions. Medicinal plants form the ‘active constituent’ component of herbal formularies. These plants have been proven with science to contain several therapeutic constituents, some of which serve as source of drugs for pharmaceutical companies.

An example is with the plant Vernonia amydalina (Bitter leaf), whose leaves contain Glycosides, tannins, saponins, sesquiterpene lactones, flavonoids, and vitamin C. It is used to treat/manage abdominal pain, Asthma, bacterial and fungal skin disorders, constipation, diabetes, helminthiasis, malaria, oliguria, pruritus, psoriasis, upper respiratory tract infections (GHP, 1992; Mshana et al., 2000).

The plant may therefore be included alongside other medicinal plants in different formulas to manufacture products for the already mentioned conditions, with each plant acting as an “active component/ingredient” instead of isolated active components as seen with pharmaceutical drugs. Constituents of plants exist in inactive states and are activated by enzymes in the body to effect healing/treatment synergistically (through combined efforts).

Availability of scientific evidence and an evidence of long time safe use of medicinal plants within a community validates inclusion in a product formulary as directed by the World Health Organization (W.H.O). It is however important to ensure compatibility of plants through the knowledge of possible herb-herb interactions before inclusion so as to obtain full responses from different doses of the resulting herbal product. Information on plant compatibilities can be obtained from licensed indigenous practitioners, plant medicine research centers, Medical herbalists, and herbal pharmacopoeias. An herbal formula for a product (like herbal mixtures) can be developed to treat more than one disease condition due to the number and nature of the plants included as against most orthodox medicines which are disease/illness specific most times. The Food and Drugs Authority (FDA) however recommends that only up to 3 disease conditions should be stated and this confirmed through product analysis by designated institutions before registration for sale/use. In the case where the product is meant for symptomatic relief only, more than 4 symptoms may be accepted by the FDA as being treated by the herbal product after analysis.

Medicinal plants used in herbal formularies exist in different classifications depending on the named conditions, according to the Handbook for Medical Herbalists, and this determines their amount in a formula. Class A plants have direct scientific and long-term folklore justification for use in a named condition, where side effects are known and can be managed. Class B plants do not have direct justification for their use in a named condition but their biological properties are adjunct to treatment of that condition. In a few cases the supporting plant part acts to reduce the side effects of Class A plants. Plants classified as Class A for one disease condition may remain Class A plants for other conditions provided there is scientific and folklore justification, else they become Class B plants to those conditions if they possess certain biological activity significant to the disease condition in question. The stem bark of Alstonia bonei (Nyame dua) although has no data of traditional use in malaria treatment, possesses antimalarial activity and may be classified as Class B in formulas meant for malaria treatment. Medicinal Plants belonging to Class C produce general wellbeing by ameliorating disturbing symptoms important to treatment of a named medical condition by Medical and indigenous herbalists. Examples include Solanum torvum fruits (Nsusuaa; Beduru; Bedru), Zingiber officinale (Ginger), etc. Effects described under C are considered palliative and only offer opportunity for natural healing to take place. These plants are usually included in herbal tonic formulas. Class D Medicinal plants are used solely for preservation, flavoring and other reason relating to formulation techniques. Plants such as Xylopia aethiopica (Hwentia), Piper guineense (soro wisa), Aframomun melegueta (Famu wisa) and Syzygium aromaticum (P3pr33) are examples of Class D plants commonly used in Ghana.

Excipients also form part of formulas used in the manufacture of different forms of herbal products. These are substances formulated alongside the active ingredients of medications/products, included for the purpose of long-term stabilization, dose compliance, enablement and control of drug bioavailability, etc. Excipients exist in two main forms; Solid dosage and solutions/suspension excipients, and may include sweetening agents, flavouring agents, thickening agents, diluents/fillers, binders, disintegrants, and preservatives. Burnt sugar, glycerol, and honeys are the most used sweetening agents in herbal products like the tonics. Starch may be used as thickening agent in the manufacturing of herbal capsules from decoctions, infusions and concoctions.

Herbal formulations comprises of mixtures/decoctions/bitters, capsules, powders, teas, tinctures, soaps, ointments, and creams. Their production involves five main stages; Plant collection, Processing, Sterilization, Preservation, and Packaging. Plant identification and collection is a very important stage in herbal product development. Certain conditions must be met before medicinal plants are collected and this varies depending on the formulation/product in question. Plants intended for use in herbal powders production must be well known, researched into, not irritable, and digestible. Those intended for formulation of herbal teas should be such that they can be formulated into powdered form to avoid stickiness in tea bags, their constituents should be water and heat soluble. Plants intended for herbal capsules should not be irritable and their constituents absorbable in the alimentary canal. It is important to collect required plants in a formulary from cultivated herbal farm than from the wild, to ensure continuous quality efficacious products and to avoid adulterants. Herbal teas should be produced from plants harvested from plantations only. Plants growing along road sides, and mining areas should not be collected as they contain carbon monoxide from car fumes, and mercury respectively.

Processing involves cleaning, drying, milling, boiling, etc employed in the production process. Harvested plants must be cleaned of debris, dried, and milled into the powdered form. This is basic to all herbal formulations or products. Other aspects such as boiling, is specific to the product in question. Plant materials (stem barks, roots, and seeds) used for decoctions/mixtures should be boiled for 1 hour and flowers/leaves boiled for 30 minutes. All the plants put together must not exceed 10%w/v. Resulting mixtures from boiling of the plants should be filtered and the filtrate allowed to cool. It is important to mask the bitter taste and colour of the filtrate with sweetening and colouring agents in accordance with stated standards in Pharmacopoeias (British or the United States Pharmacopoeia). For herbal teas, the plants should be milled and sieved to obtain uniform size, the taste masked and dried. Excipients like starch are required in the production of herbal capsules to help disperse the powder for effective absorption and bioavailability. Plant powders used in others such as ointments, soaps, creams and showel gel should be processed as stated earlier before observing other standards of production.

Product sterilization is also an important stage in herbal product development. It sorts to kill harmful organisms present in harvested plants from plantations or the wild. Heat sterilization ovens can be used to sterilize plant materials. The plant powder together with excipients (for teas, and capsules), should be placed in oven shelves and set oven at 60-80oC. Powders for oinments, etc, should be sterilized singly and the excipients added after the products have been formulated in accordance with acceptable standards. Flower materials are left for 30 minutes. Roots, barks, and leaves left for 1 hour to kill spores, etc.

Preservation of herbal products helps maintain the required conditions like pH over the period for which the products are indicated for use. Dosage forms such as herbal ointments, soaps, and shower gels, may not require preservatives as the substances used (sodium laureth sulphate/soap base, petroleum jelly, soft paraffin) are self- preserving in nature. The benzoates have been approved by the FDA for use as preservatives for herbal mixtures or liquid herbal products. Methyl & propyl pyramate (ratio 5 methyl to 3propyl) may be used in place of benzoates. Maximum of 0.3%w/v of preservative should be used to preserve any liquid herbal product.

Packaging and labeling is the final stage of product development. Every product form has its suitable packaging container meant to hold manufactured medicine in good state until the stated expiry period. Packaging help protect against absorption of water/moisture from the atmosphere, exposure to sunlight/heat, etc, to prevent the breakdown of active principles contained in herbal products. It should be done in a closed and neat environment, devoid of contamination and the people involved wearing recommended head caps, nose masks, foot wears, and gloves. Products should be well corked/covered tightly and labelled according to laid out standards. Sterilized powders should be left to cool in the heating oven before packaging. Herbal mixtures/decoctions should also be left to cool and the recommended excipients added before bottling and labelling.

Powders meant for capsulation should also be left to cool in the oven after sterilization, excipients added before packing them in the required capsule shells (exist in 250mg, 500mg, 1g, etc). The type of capsule shells used depends on the expected dose as determined by the stipulated standards. For capsules produced from powders obtained from the evaporation of decoctions/mixtures (the ideal way), starch may be added along side other excipients to the cooled powder after sterilization before packaging.

Ointments, and creams should be poured into the containers whiles hot and allowed to set before being covered and labelled appropriately. A good label should provide vital information like the name of product, storage conditions, dosage, active constituents and excipients, batch number, manufacturing date, expiry date, address of manufacturer, FDA registration number, indications, contraindications, and product strength.

Plants have been proven to be safe but the safety of herbal products is only guaranteed after the Pharmacopoeia or product manufacturing standards have been observed and confirmed by the FDA through product analysis and registration. Proper storage of registered herbal products is as important as good manufacturing processes (GMP). Pharmacies, licensed chemical shops and licensed herbal shops are meant to observe all drug/medicine storage requirements by their various regulatory authorities/councils. Herbal products are not to be sold in buses, in the open, and other unrecommended places. Medicines sold in buses most of the time are poorly produced, not FDA certified, and poorly packaged and labelled. Oral testimonies and display of practice licenses in buses and other places should not be the basis for purchase but instead FDA certification and recommendation or prescription from Medical Herbalists (M. H) or Medical Doctors.

BENTIL Emmanuel Asare Adusei
BSC Herbal Medicine, KNUST.
[email protected]

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