Pharmaceutical Excipients

• Pharmaceutical excipients are substances formulated alongside the active pharmaceutical ingredient (API) in medications.
• Excipients are pharmacologically inactive.

Purposes of Excipients

• Provide bulk to the formulation.
• Facilitate drug absorption/solubility and other pharmacokinetic considerations.
• Aid in handling of the API during manufacturing.
• Provide stability and prevent denaturation.

Ideal Excipient Properties

• Stable and reproducible
• No unwanted interaction with the drug
• Pharmacologically inert
• Has desired functionality
• Cost-effective

Types of Pharmaceutical Excipients

• Fillers
• Binders
• Coating Agents
• Anti-adherents
• Preservatives
• Antioxidants
• Flavouring Agents
• Colouring Agents
• Sweetening Agents
• Disintegrants
• Sorbents
• Glidants
• Lubricants

Fillers

• Fillers increase the size of a tablet or capsule.
• This increase in size makes production practical and use convenient.
• Fillers add volume and/or mass to a drug substance for precise metering and handling.
• Fillers are used in tablets and capsules.
• A good filler is inert, compatible with other components, non-hygroscopic, cheap, compactable, tasteless or pleasant tasting.
• Examples of fillers are plant cellulose, dibasic calcium phosphate, lactose, mannitol, sorbitol, calcium carbonate, and magnesium stearate.
• Vegetable fats and oils are used in soft gelatine capsules.

Binders

• Binders hold the ingredients in a tablet together.
• Binders ensure tablets & granules have the mechanical strength and give volume to low active dose tablets.
• A binder is compatible with other constituents, and add cohesion to powders.

Classification of Binders by Application

• Solution binders are dissolved in a solvent, such as water or alcohol.
• Dry binders are added to powder, like cellulose, methyl cellulose, polyvinyl pyrrolidone, and polyethylene glycol.

Disintegrants

• Disintegrants are substances or mixtures added to drug formulations.
• Disintegrants facilitate dispersion or breakup of tablets and capsule contents into smaller particles for quick dissolution upon contact with water in the GIT.
• Disintegrants should have good hydration capacity
• Disintegrants should have poor solubility and gel formation capacity.
• Examples of disintegrants include polyvinylpyrrolidone, carboxymethyl cellulose, and sodium starch glycolate.

Coating Agents

• Coating is a process where a dry, outer layer of coating material is applied to the surface of a dosage form.
• Coating agents are what is used in the coating process.
• Three types of coating agents used pharmaceutically are film coating, sugar coating, and compressions coating.
• Coating agents provide protection, masking, elegance, ease of swallowing, and identification.

Sorbents

• Sorbents soak up oil from water
• Natural sorbents include peat moss, sawdust, feathers, and anything else natural containing carbon.
• Synthetic sorbents include polyethylene and nylon.
• Sorbents are used for tablet/capsule moisture-proofing by limiting fluid.

Anti-adherents

• Anti-sticking keeps the surface of the tablet sticking to the die walls and the punches.
• Water-insoluble lubricants (magnesium stearate, talc & starch) are used as anti-adherents.

Lubricants

• Lubricants prevent ingredients from clumping together and from sticking to tablet punches or capsule filling machines.
• Lubricants make sure that tablets are formed and ejected with little friction between the solid substance and the die wall.

Types of Lubricants

• Hydrophilic lubricants are poor lubricants with no glidant or anti-adherent properties.
• Hydrophobic lubricants are the most widely used and effective at low concentrations.
• Hydrophobic lubricants also have anti-adherent and glidant properties.
• Magnesium stearate is an example.

Roles of Lubricants

• True Lubricant Role: Decrease friction between the tablet surface & die wall during ejection and reduce wear on punches.
• Anti-adherent Role: Prevent sticking to punch faces or in encapsulation.
• Glidant Role: Enhance product flow by reducing interparticle friction.
• Polyethylene glycol, magnesium stearate, and stearic acid/derivatives are lubricant examples.

Glidants

• Glidants are substances like colloidal silica that enhance flow of a granular mixture.
• Glidants reduce inter-particle friction & are used in pharmaceutical production of tablets & capsules.
• Glidants are used to promote powder flow reducing interparticle friction & cohesion.
• Glidants are used with lubricants, since Glidants don't reduce die wall friction.
• Fumed silica, talc, & magnesium carbonate are examples.

Preservatives

• Added to various food and pharmaceutical products to prolong shelf life.
• Preservative systems protect the product against microbial proliferation without compromising product performance.
• Preservatives must exert a wide spectrum of antimicrobial activity at low inclusion levels.
• Preservatives must maintain activity throughout product manufacture, shelf life, and usage.
• Preservatives should not compromise product quality, performance, pack, or delivery system.
• Preservatives should not adversely affect patient safety or tolerance of product.
• Examples are methyl & ethyl parabens, propyl paraben, benzoic acid & its salts, and sorbic acid and its salts.

Antioxidants

• Antioxidants are molecules inhibiting the oxidation of other molecules by transfering electrons or hydrogen from a substance to an oxidizing agent.
• Antioxidants must be effective at a low, nontoxic concentration level.

Ideal Properties of Antioxidants

• Stable and effective under normal conditions of use, over a wide pH and temperature range.
• Soluble at the needed concentration.
• Compatible with drugs and pharmaceutical excipients.
• Free from objectionable odor and taste.
• Colorless in both original and oxidized form.
• Non-toxic both internally & externally at the required conc.
• Unreactive (does not adsorb, penetrate, or interact) with containers or closures.
• Antioxidants should be cost-effective
• BHT (Butylated Hydroxy Toluene), BHA (Butyl Hyd Anisol), and sodium sulfite are examples.

Sweetening Agents

• Sweetening agents are used in liquid formulations to increase palatability of the therapeutic agent.
• Sucrose, saccharine, aspartame, and sorbitol are examples.
• The main agents used in oral preparations are sucrose, liquid glucose, glycerol, sorbitol, saccharin sodium & aspartame.
• Aspartame is an artificial sweetening agent.
• Use of sugars in oral formulations for children and patients with diabetes mellitus must be avoided.

Flavoring Agents

• Flavoring agents are added to increase patient acceptance.
• The four basic taste sensations are salty, sweet, bitter, and sour.
• Certain flavors are used to mask these specific taste sensations.
• Clove oil, citric and syrup, glycerin, rose oil, orange oil, and menthol are examples.

Coloring Agents

• Coloring agents are pharmaceutical ingredients that impart the color
• There are two types of coloring agents, natural and synthetic.

Pharmaceutical excipients are inactive substances formulated alongside active pharmaceutical ingredients (APIs) in medications. They serve various purposes, including providing bulk, facilitating drug absorption, aiding in manufacturing, and ensuring stability. Ideal excipients are stable, non-reactive, pharmacologically inert and cost-effective.