Herbal Formulation

As per PCI Syllabus

(T. Y. B. Pharm Sem –VI)  Unit-III


HERBAL FORMULATION


Herbs have been used in a wide variety of dosage forms, large number of herbal formulations containing the plants or their extracts with proven medicinal activity are being Used.

Herbal formulations may contain a single herb or combinations of different herbs.

With the advances of pharmaceutical technology, modern dosage forms have evolved. Herbal formulations/ dosage forms can be broadly classified into three categories viz:

i.Traditional dosage forms

These are derived from various traditional systems of medicines like Ayurveda, Unani, Homeopathy, etc. Eg.: pills, powders, semi fluid extracts, pellets, tinctures, etc.

ii. Modern herbal dosage forms 
These formulations are developed from modern technological processes. Modern herbal formulations offer small dosage size, they are user friendly, convenient and have good absorption characteristics.
Eg: tablets, capsules, syrups, solutions, suppositories, injections.

iii. Novel drug delivery  stems (NDDS) Novel dosage  forms

With the advancement in different scientific techniques of preparing formulations, novel dosage forms are being developed to overcome the limitations of conventional dosage forms such as tablets, syrups, solutions, etc. 

Many novel dosage forms have been developed successfully which have offered better acceptance by the health system. A few novel dosage forms available in the market are transdermal patches, implants, nasal systems, microcapsules, microspheres, liposomes, phytosomes, etc.



Herbal Syrup

These are preparations formulated by incorporating sugar solution with plant extracts such as infusions, decoctions, juices, fermented products or simple solutions. Honey or unrefined sugar is used to prepare syrups as they act as good preservatives.

Herbal syrups are made with equal proportions of herbal extracts with honey or sugar solution of known concentration. Various flavours like orange, raspberry, menthe can also be added to mask the bitter taste as well as improve the palatability of the formulation.

HERBAL TABLET

These are solid dosage forms of powdered herbs, herbal extracts or their constituents prepared by moulding or compression.

In addition to the active ingredients, these contain diluents like binding agents which provide strength to withstand normal handling while transportation and storage, colouring agents to improve the appearance, sweetening and flavouring agents to mask the bitter taste, disintegrating agents to facilitate the breakdown and absorption in the gastrointestinal tract are added.

HERBAL OINTMENTS

These are semisolid dosage forms meant for external application to the skin or mucous membrane. Ointments perform softening (emmolient) and protective action.

Waxes like bees wax, paraffin wax are used as base or carrier. Various active herbal ingredients in the form of powders, dried extracts can be incorporated in the bases which provide therapeutic benefits.

HERBAL CREAM
These are viscous, semisolid preparations which may be oil in water type (aqueous) creams or water in oil type (oily) creams. 

HERBAL MIXTURE

These are the preparations containing combination of two or more herbal ingredients which are formulated into various formulations like tablets, capsules, ointments, creams, etc.
These mixtures or combinations of herbal ingredients may have more than one activity and can be used to treat multiple ailments or they may produce additive or synergistic effects for a single disease. 

Novel Drug Delivery Systems (NDDS)/ Novel Dosage Forms

a) Phytosomes

The concept of Phytosomes is another breakthrough for the development in herbal drug technology.

Phytosomes contain active herbal ingredients surrounded and bonded by phospholipids.

They are produced by bonding phosphatidyl choline with the ingredients thereby producing a complex.

The phospholipid structure has a water soluble choline head and fat soluble body and tail (phosphatidyl portion).

Herbal nano particles are colloidal system with particle size of about 1 to 1000 nm.

The choline head (water soluble) binds with the active compounds (herbal ingredients), while the phosphatidyl portion (fat soluble) comprising of body and tail envelops the choline bound materials (*i.e. active ingredients) as a result microspheres or vesicles are produced whereby the valuable components of the herbs are protected.

Phytosomes enhance the absorption and improve the bioavailability of herbal ingredients by enhancing their delivery to the tissues thereby lowering its dose and reducing the side effects.
 They also protect the active herbal ingredients from destruction by the digestive juices and gut bacteria.

Several studies have shown that the body uses phytosome molecules more effectively than that of non phytosome molecules.

b) Liposomes

These are prepared by incorporating the active ingredients inside the microscopic double layered membranes which are made of phospholipids (known as phospholipid vesicles).
These vesicles are suspended in an aqueous solvent uniformly. Drugs incorporated in the liposomes can be delivered to the desired site in desired concentrations.
This novel drug delivery system is especially targeted to liposomal delivery of drugs in cancer chemotherapy, arthritis, haemophilia and diseases of the immune system. 

c) Nano particles

These are colloidal particles of the submicron size which act as carriers for drug molecules.
These are used to target various sites in the treatment of cancer, disease of the reticulo endothelial system and enzyme replacement therapy in liver. 

d) Microspheres

These are small, solid particulate carriers containing the dispersed drug particles either in solution or crystalline form.

Microspheres are used as carriers for drugs and therapeutic agents especially in cancer treatment and hormonal disorders.  


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