Pharmaceutical Excipients, Slides of Pharmacy

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Pharmaceutical Excipients

Faria Tasneem

Lecturer, Department of Pharmacy

University of Asia Pacific

Excipients/Additives

Excipients come from Latin “ Excipere ”, meaning “other than”. Pharmaceutical Excipients are substances other than the active medicament(s) which are included in the manufacturing process or are contained in the finished pharmaceutical dosage form. Functions of Excipients: I. Aid the manufacturing procedure II. Enhancing stability, bioavailability and patient acceptability III. Increasing overall safety and effectiveness of drug products during storage and use IV. Facilitating administration of the drug by the intended route V. Improving dosing compliance (to give a shape and to improve

palatability, elegance of the formulation)

o Should be economic and readily available o Should have no therapeutic activity of its own, should offer only its desired functionality o Should be odorless, colorless and tasteless o They should be effective in low concentration over a wide range of pH o They should be soluble in water as well as oil & fat

Different Types of Formulations

Dosage Forms Solid Tablets Capsules Semi Solid Cream Suppositories Liquid Monophasic Syrup Solution Biphasic Emulsion Suspension Gas Aerosols

Excipients of Capsule

Capsules are solid dosage forms in which the drug substance is enclosed in either a hard or soft soluble container or shell of a gelatin or other suitable material. Excipients commonly used in capsules are: ➢ Surfactants ➢ Preservatives ➢ Protective Coating/Coating agents ➢ Flavoring agents ➢ Coloring agents

• Additives of powder filled capsules are: ➢ Diluent ➢ Lubricant ➢ Glidants ➢ Wetting Agents

Excipients of Semisolid Dosage Forms

Ointments, creams, suppositories and gels are semisolid dosage forms intended for topical application. They may be applied to the skin, placed on the surface of the eye, or used nasally, vaginally, or rectally. Some additives used in semisolid preparations are:- ➢Vehicles ➢Emulsifiers ➢Emollients ➢Permeation Enhancers ➢Preservatives

Excipients of Biphasic Liquids

Pharmaceutical suspension is a course dispersion of finely divided, insoluble solid particles (dispersed phase) in a liquid medium (continuous phase). The excipients of suspension are: ➢ Vehicle/Solvent ➢ Co-solvent ➢ Buffering agents ➢ Surfactants ➢ Preservatives ➢ Suspending agents ➢ Antioxidants ➢ Anti-foaming agents

Emulsion is a two-phase system prepared by combining two immiscible liquids in which small globules of one liquid are dispersed uniformly (dispersed phase) throughout the other liquid (continuous phase). Additives of pharmaceutical emulsions include: ➢ Emulsifying agent ➢ Antioxidant ➢ Buffering agent ➢ Preservative ➢ Solvent/Vehicle ➢ Co-solvent ➢ Flavoring agent

Diluent/Filler

Frequently, the single dose of the active ingredient is small, and an inert substance is added to increase the bulk to make the tablet a practical size for compression. This function is provided by diluents. Example : Calcium carbonate, Calcium sulfate, Microcrystalline cellulose (MCC), Powdered cellulose, Dextrose, Kaolin, Lactose, Mannitol, Starch, Sucrose etc. Lactose is among the most common diluents because it dissolves readily in water, has a pleasant taste, is non hygroscopic and has a good compatibility with other excipients. However, its main limitation is that some people have an intolerance to lactose.

Disintegrants

A disintegrant is added to most tablet formulations to facilitate a break down or disintegration of the tablet into smaller particles when it contacts with water in the gastrointestinal tract. Disintegrants may function by drawing water into the tablet, swelling, and causing the tablet to burst apart. Such tablet fragmentation with greater surface area may be critical to the subsequent dissolution of the drug and to the attainment of satisfactory drug bioavailability. Example: Alginic acid, Sodium alginate, Microcrystalline cellulose (MCC), Sodium starch glycolate, Crosslinked polymers (e.g. Crosslinked polyvinylpyrrolidone) etc. Sodium starch glycolate and crosslinked PVP (Crospovidone) work as “Superdisintegrants”. The mechanism by which Na starch glycolate works involves rapid absorption of water, leading to an enormous increase in volume of granules that result in rapid and uniform disintegration.

Binders can be added to a powder in different ways: ➢ As a solution which is used as agglomeration liquid during wet agglomeration. The binder here is often referred to as a solution binder. ➢ As a dry powder which is mixed with other ingredients before compaction (slugging or tableting). The binder here is often referred to as a dry binder. Examples: Alginic acid, Sodium alginate, Carboxymethyl cellulose sodium (Sodium CMC), Microcrystalline cellulose (MCC), Dextrin, Dextrose, Hydroxypropyl cellulose (HPC), HPMC, Lactose etc.

Glidant/Anti-adherent

These products facilitate the movement of the powder i.e. enhance the flow property of powder by reducing the interparticle friction and help granulation prior to compaction, compression, or encapsulation. By facilitating flow of the material, there is less weight variability of the dosage form, resulting in more consistent dosing of the active ingredient(s). Examples: Talc, Colloidal silicon dioxide etc.

Coloring Agents

Coloring agents may be defined as the substances that are used to impart color to foods, drugs and cosmetics for increasing their organoleptic properties, imparting the preferred color to the formulation and enhancing the product quality. They are also used for: ➢Product identification ➢Increasing product acceptability to the patients Sources: A. Natural coloring agents I. Minerals : Frequently termed as pigments, they are used to color lotions, cosmetics, and other preparation for external use. Examples include: Ferric oxide (yellow and red), Carbon black, Titanium dioxide, Prussian blue etc. II. Plants: Chlorophyll, Indigo, Alizarin, Carotenoids, Flavones III. Animals: The animal world has been comparatively a minor source of colors. e.g. Tyrian blue, Cochineal etc.

B. Synthetic coloring agents: The synthetic colors are prepared from coal tar dyes. e.g. Nitro-dyes, Nitroso-dyes, Azo-dyes (e.g. lemon yellow Tartrazine), Thiazine etc. Flavoring Agents Flavoring agents are the substances which are used to impart pleasant smell to the preparation and to mask specific type of taste of the preparation, making them more palatable. They improve patient acceptance. The four basic taste sensations are salty , sweet , bitter and sour , and flavors should be used to mask these specific taste sensations. Example: Vanillin, Menthol, Cinnamon, Wintergreen, Peppermint, Ginger, Raspberry, Citric acid monohydrate etc.