Herbal Excipients

As per PCI Syllabus

(T.Y. B. Pharm Sem –VI) Unit-III
HERBAL EXCIPIENTS

Excipients/ Pharmaceutical aids are the substances which are inert and have little or no therapeutic value, but are essential in the manufacture of various pharmaceutical dosage forms such as tablets, capsules, syrups, etc.

Excipients are mixed with the active ingredients to make up the volume or improve the stability or mask the bitter taste or improve the appearance, odour and other characteristics of the dosage forms.

Binding agents, suspending agents, viscosity builders, disintegrating agents, etc  also constitute pharmaceutical excipients/ aids.

Advantages/ significance of herbal excipients

 i. Biodegradable

Naturally occurring substances show no adverse effects on the environment or other living beings and they are easily biodegradable.or  Biodegradable are the substances which can be easily taken back into the earth naturally without causing any harm to the environment.

ii. Biocompatible and nontoxic

Most of the herbal excipients are carbohydrates in nature. They are compatible and non toxic with most of the ingredients.

iii. Economic

Herbal excipients are cheaper and their cost of production is comparatively lesser.

iv. Safe and free from side effects

Naturally occurring excipients are safer and without any side effects.

V. Easily available

Natural excipients are produced in most of the countries, hence easily available.


Disadvantages of herbal excipients

i. Microbial contamination Microbial contamination occurs due to improper processing as well as presence of excessive amounts of moisture in the raw material.
During production, herbs are exposed to external environment hence there are Chances of microbial contamination.

ii. Biochemical variation : Variation in the quality of product may occur due to various environmental factors.

iii. Uncontrolled rate of hydration:  This occurs due to biochemical variation and difference in the quality of materials from one batch to another.

iv. Heavy metal contamination : Herbs are always associated with the risk of heavy metal contamination.




Colorants: Eg. henna, chlorophyll, caramel, amaranth, indigo.
Sweeteners: Eg: glycyrrhiza, honey, stevia.
Binding  agents: Eg: acacia, gelatin, tragacanth, starch.
Diluents. Eg: lactose, starch, mannitol, sucrose.
Viscosity builders: Eg: pectin, tragacanth, cellulose, guar gum, gelatin.
Disintegrating  agents: Eg. Starch, isapgol husk, carboxy methyl cellulose.
Ointment bases: Eg: lanolin, bees wax.
Emulsifying: agents: Eg: acacia, agar, guar gum, methyl cellulose.
Flavouring  agents: Eg: cardamom, vanilla, lemon oil, orange oil.
Perfumes: Eg: rose, lavender, sandalwood.

STUDY OF HERBS USED AS EXCIPIENTS

Henna

It consists of dried leaves of Lawsonia inermis
Family: Lythraceae.

Chemical constituents: Henna contains lawsone as its chief constituent, Other constituents include phenols, coumarins, flavonoids and tannins.

Uses: colouring agent.

Amaranth

It consists of flowers of Amaranthus hypochondriacus and other species of Amaranthus,
Family: Amaranthaceae.


Chemical constituents: It contains polyphenols, vitamins and flavonoids.

Uses: dyeing agent

Madder

It consists of dried root of Rubia tinctorum
Family: Rubiaceae.


Chemical Constituents: Anthraquinone alizarin, the hydrolysis product of ruberythric acid, is the main dye component of Rubia tinctorum. It contains several anthraquinone glycosides.

Uses: Madder root contains the anthraquinone pigment alizarin and has been since ancient times a popular fine red dye plant.

Liquorice

It consists of dried roots and stolons of Glycyrrhiza glabra, 
Family: Leguminosae.


Chemical constituents: It contains glycyrrhizinic acid, liquiritin, isoliquiritin.

Uses: Sweetening agent.

Stevia

It consists of the plant Stevia rebaudiana
Family: Compositae.

Chemical constituents: It contains stevioside, rebaudioside, steviol.

Uses: Sweetening agent. 

Acacia

It is the dried gummy exudation obtained from the stems and branches of Acacia Arabica
Family: Leguminosae.

C.C.: It contains sugars like arabinose, galactose, rhamnose and glyceronic acid.

Uses: Acacia is used as binding agent, suspending  agent,  emulsifying agent and Viscosity builder. 

Saffron 

Saffron is the dried stigma and style tops of Crocus sativus Linn. 
Family Iridaceae.

C.C.: The Saffron contains volatile oil (1.3%), fixed oil, and wax. Crocin is the chief colouring principle in Saffron. crocetin (an aromatic compound), gentiobiose, α- and γ-carotenes, lycopene, zeaxanthin, β-sitosterol, palmitoleic, oleic, linoleic, & linolenic acids.

Uses: Saffron is used in fevers, cold, as colouring and flavouring agent, cosmetic pharmaceutical preparations, and as spice.


 Gelatin

 It is a protein obtained by partial hydrolysis of  animal connective tissue like bone skin, tendons and ligaments.

C.C.: Gelatin chemically contains ammo acids like glycine, alanine, glutamic acid, proline, argginine, aspartic acid, leucine, isoleucine.

Uses: Binding agent, thickening agent, emulsifying agent, in the manufacture of capsules. 


Tragacanth

It is the dried gummy exudation obtained from the stem and branches of Astragalus gummifer, 
Family: Leguminosae.

Chemical constituents: lt contains gums, tragacanthin and bassorin.

Uses: Binding agent and Viscosity builder. 

Lactose
It is a natural disaccharide obtained from milk.
Chemical constituents: It contains sugars galactose and glucose.
Uses: Diluent in tablets and capsules. 

Mannitol

It is a saccharine exudation from the stems of Fraxinus ornus,
Family: Oleaceae.
It is a white, crystalline, odourless, non hygroscopic sweet powder. It is freely soluble in water and insoluble in alcohol.
Uses: Sweetening agent and diluent. 

 Guar gum
It is the ground endosperm of seeds  of Cyamopsis tetragonlobus, 
Family: Leguminosae

Chemical constituents: It contain 85% guran, galactose, mannose.

Uses: Binding agent, disintegrating agent, suspending agent and emulsifying agent. 

Starch

It consists of polysaccharide granules obtained from the grains of maize, rice, wheat potatoes.

Chemical constituents: It contains water soluble amylase and water  Insoluble amylopectin, which swells and is responsible  for gelatinizing properly of starch.

Uses: It is used as binding agent, disintegrating agent and diluent. 

Sandalwood oil

It is the volatile oil obtained by steam distillation of heart Wood of Santalum album,
Family: Santalaceae.

Chemical constituents: lt contains sesquiterpene alcohol namely alpha and beta-santalol.

Uses: Used in perfumery industry. 

Rose oil

It is a volatile oil distilled from fresh flowers of Rosa gallica and other rose species,
Family: Rosaceae.
Chemical constituents: Rose oil contains linalool, nerol, citronellal and geraniol.

Uses: Used in perfumes and flavouring agent. 

 Cardamom oil

 It is a volatile oil distilled from the seeds of Elettaria cardamomum,
Family: Zingiberaceae.

Chemical constituents: It contains cineol, alpha terpinyl acetate, terpeneol, borneol and sabinene.

Uses: Used as a flavouring agent. 

 Orange oil

It is a volatile oil obtained by expression from fresh peels of the ripe fruits of Citrus limonis,
Family: Rutaceae.

C.C.: Orange oil contains limonene, citral, citronellal.

Uses: Used as a flavouring agent.