Excipients Definition: Excipients in pharmaceuticals are substances other than the active pharmaceutical ingredient (API).
To produce a drug substance in a final dosage form requires pharmaceutical excipients.
For example, in the preparation of solutions, one or more solvents are used to dissolve the drug substance, flavors and sweeteners are used to make the product more palatable, colorants are added to enhance the appeal, preservatives may be added to prevent microbial growth, and stabilizers, such as antioxidants and chelating agents, may be used to prevent decomposition.
For the preparation of tablets, diluents or fillers are commonly added to increase the bulk of the formulation, binders to cause adhesion of the powdered drug and pharmaceutical substances, anti-adherent or lubricants to assist smooth tablet formation, disintegrating agents to promote tablet breakup after administration, and coatings to improve stability, control disintegration, or enhance appearance.
Ointments, creams, and suppositories acquire their characteristic features from their pharmaceutical bases. Thus, for each dosage form, the pharmaceutical ingredients establish the primary features of the product and contribute to the physical form, texture, stability, taste, and overall appearance.
PHARMACEUTICAL EXCIPIENTS/INGREDIENTS
| Ingredient/ Excipient | Example |
| Example | Conc.(%) |
| Preservatives: Used in liquid and semisolid preparations to prevent | Based on chemical Class | Acidic | Phenol | 0.2-0.5 |
| Chlorocresol | 0.05-0.1 | |||
| O-Phenyl phenol | 0.005-0.1 | |||
| Alkyl ester of parahydroxybezoic acid | 0.001-0.2 | |||
| Benzoic acid & its salts | 0.1-0.3 | |||
| Boric acid & Its salt | 0.5-1.0 | |||
| Sorbic acid & Its salt | 0.05-0.2 | |||
| Neutral | Chlorobutanol | 0.5 | ||
| Benzyl alcohol | 0.1 | |||
| Beta- Phenylethyl alcohol | 0.2-1.0 | |||
| Mercurial | Thimerosal | 0.001-0.1 | ||
| Phenylmercuric acetate & Nitrate | 0.002-0.005 | |||
| Nitromersol | 0.000-0.1 | |||
| QAC (Quaternary Ammonium Compound) | Benzalkonium chloride | 0.004-0.02 | ||
| Cetypyridimium | 1.01-0.02 | |||
| Based on Micro-organism | Antifungal | Butylparaben Ethylparaben Methylparaben Benzoic acid Propylparaben Sodium benzoate Sodium propionate |
| |
| Antimicrobial | Benzoic acid & Its salt Ex.Benzalkonium chloride etc |
| ||
| Content provided by http://thepharmapedia.com/ | ||||
| Antioxidant: Used to prevent deterioration of preparations by oxidation | Compounds | Reducing agent Antioxidant | Ascorbic acid | 0.02-0.1 |
| Sod. Bisulfite | 0.1-0.15 | |||
| Sod. Metasulfite | 0.1-0.15 | |||
| Sof. Formaldehyde sulfoxylate | 0.1-0.15 | |||
| Thoiurea | 0.005 | |||
| Blocking agent Antioxidant | Ascorbic acid esters | 0.1-0.15 | ||
| BHT (Butyl hydroxytoluene), BHA | 0.005-0.02 | |||
| Tocopherol/vit E | 0.05-0.075 | |||
| Chelating agent as antioxidant | EDTA (Ethylenediaminetetraacetic acids) | 0.01-0.075 | ||
| Content provided by http://thepharmapedia.com/ | ||||
| Synergists antioxidant | Ascorbic acis | 0.01-0.05 | ||
| Citric acid | 0.005-0.01 | |||
| Citraconic acid | 0.03-0.45 | |||
| Phosphoric acid | 0.005-0.01 | |||
| Tartaric acid | 0.01-0.02 | |||
| Air displacement | Nitrogen gas | Agent employed to displace air (oxygen) in a hermetically sealed container to enhance product stability | ||
| Ingredient/ Excipient | Definition | Example |
| Adsorbent | An agent capable of holding other molecules onto its surface by physical or chemical (chemisorption) means | Powdered cellulose Activated charcoal |
| Acidifying agent | Used in liquid preparations to provide acidic medium for product stability | Citric acid Acetic acid Fumaric acid Hydrochloric acid Nitric acid |
| Alkalinizing agent | Used in liquid preparations to provide alkaline medium for product stability | Ammonia solution Ammonium carbonate Diethanolamine Monoethanolamine Potassium hydroxide Sodium bicarbonate Sodium borate Sodium carbonate Sodium hydroxide Trolamine |
| Aerosol propellant | Agent responsible for developing the pressure within an aerosol container and expelling the product when the valve is opened | Carbon dioxide Dichlorodifl uoromethane Dichlorotetrafl uoroethane Trichloromonofl uoromethane |
| Buffering agent | Used to resist change in pH upon dilution or addition of acid or alkali | Potassium metaphosphate Potassium phosphate, Monobasic Sodium acetate Sodium citrate, Anhydrous and dihydrate |
| Chelating agent | Substance that forms stable water-soluble complexes (chelates) with metals; used in some liquid pharmaceuticals as stabilizers to complex heavy metals that might promote instability. In such use, they are also called sequestering agents | Edetic acid Edetate disodium |
| Colorant | Used to impart color to liquid and solid (e.g., tablets and capsules) preparations | Caramel, Ferric oxide & Regulatory approved color |
| Clarifying agent | Used as a filtering aid for its adsorbent qualities | Bentonite |
| Content provided by http://thepharmapedia.com/ | ||
| Emulsifying agent | Used to promote and maintain dispersion of finely subdivided particles of liquid in a vehicle in which it is immiscible. End product may be a liquid emulsion or semisolid emulsion | Acacia Cetomacrogol Cetyl alcohol Glyceryl monostearate Sorbitan monooleate Polyoxyethylene 50 stearate
|
| Encapsulating agent | Used to form thin shells to enclose a drug for ease of administration | Gelatin |
| Flavorant | Used to impart a pleasant flavor and often odor to a preparation. In addition to the natural flavorants listed, many synthetic ones are used | Anise oil Cinnamon oil Cocoa Menthol Orange oil Peppermint oil Vanillin |
| Humectant | Used to prevent drying of preparations, particularly ointments and creams | Glycerin Propylene glycol Sorbitol |
| Levigating agent | Liquid used as an intervening agent to reduce the particle size of a powder by grinding, usually in a mortar | Mineral oil Glycerin Propylene glycol |
| Ointment base | Semisolid vehicle for medicated ointments | Lanolin Hydrophilic ointment Polyethylene glycol ointment Petrolatum Hydrophilic petrolatum White ointment Yellow ointment Rose water ointment |
| Plasticizer | Component of fi lm-coating solutions to make fi lm more pliable, enhance spread of coat over tablets, beads, and granules | Diethyl phthalate Glycerin |
| Solvent | Used to dissolve another substance in preparation of a solution; may be aqueous or not (e.g., oleaginous). Cosolvents, such as water and alcohol (hydroalcoholic) and water and glycerin, may be used when needed. Sterile solvents are used in certain preparations (e.g., injections) | Alcohol Corn oil Cottonseed oil Glycerin Isopropyl alcohol Mineral oil Oleic acid Peanut oil Purifi ed water Water for injection Sterile water for injection Sterile water for irrigation |
| Stiffening agent | Used to increase thickness or hardness of a preparation, usually an ointment | Cetyl alcohol Cetyl esters wax Microcrystalline wax Paraffi n Stearyl alcohol White wax Yellow wax |
| Suppository base | Vehicle for suppositories | Cocoa butter Polyethylene glycols (mixtures) PEG 3350 |
| Surfactant (surface active agent) | Substances that absorb to surfaces or interfaces to reduce surface or interfacial tension. May be used as wetting agents, detergents, or emulsifying agents | Benzalkonium chloride Nonoxynol 10 Octoxynol 9 Polysorbate 80 Sodium lauryl sulfate Sorbitan monopalmitate |
| Suspending agent | Viscosity-increasing agent used to reduce sedimentation rate of particles in a vehicle in which they are not soluble; suspension may be formulated for oral, parenteral, ophthalmic, topical, or other route | Agar Bentonite Carbomer (e.g., Carbopol) Carboxymethylcellulose sodium Hydroxyethyl cellulose Hydroxypropyl cellulose Hydroxypropyl methylcellulose Kaolin Methylcellulose Tragacanth Veegum |
| Sweetening agent | Used to impart sweetness to a preparation | Aspartame Dextrose Glycerin Mannitol Saccharin sodium Sorbitol Sucrose |
| Tablet-Antiadherents | Prevent tablet ingredients from sticking to punches and dies during production | Magnesium stearate |
| Tablet binders | Substances used to cause adhesion of powder particles in tablet granulations | Acacia Alginic acid Carboxymethylcellulose sodium Compressible sugar (e.g., Nu-Tab) Ethylcellulose Gelatin Liquid glucose Methylcellulose Povidone Pregelatinized starch |
| Tablet and capsule diluent | Inert filler to create desired bulk, fl ow properties, and compression characteristics of tablets and capsules | Dibasic calcium phosphate Kaolin Lactose Mannitol Microcrystalline cellulose Powdered cellulose Precipitated calcium carbonate Sorbitol Starch |
| Tablet coating agent | Used to coat a tablet to protect against decomposition by atmospheric oxygen or humidity, to provide a desired release pattern, to mask taste or odor, or for aesthetic purposes. Coating may be sugar, fi lm, or thick covering around a tablet. Sugar-coated tablets generally start to break up in the stomach. Film forms a thin cover around a formed tablet or bead. Unless it is enteric, film dissolves in the stomach. Enteric coating passes through the stomach to break up in the intestines. Some water-insoluble coatings (e.g., ethylcellulose) are used to slow the release of drug in the gastrointestinal tract | Content provided by http://thepharmapedia.com/ |
| Sugar coating | Content provided by http://thepharmapedia.com/ | Liquid glucose Sucrose |
| Film coating | Content provided by http://thepharmapedia.com/ | Hydroxyethyl cellulose Hydroxypropyl cellulose Hydroxypropyl methylcellulose Methylcellulose (e.g., Methocel) Ethylcellulose (e.g., Ethocel) |
| Enteric coating | Content provided by http://thepharmapedia.com/ | Cellulose acetate phthalate Shellac (35% in alcohol, pharmaceutical glaze) |
| Tablet direct compression excipient | Used in direct compression tablet formulations | Dibasic calcium phosphate (e.g., Ditab) |
| Tablet disintegrates | Used in solid forms to promote disruption of the mass into smaller particles more readily dispersed or dissolved | Alginic acid Polacrilin potassium (e.g., Amberlite) Sodium alginate Sodium starch glycolate Starch |
| Tablet glidant | Used in tablet and capsule formulations to improve flow properties of the powder mixture | Colloidal silica Cornstarch Talc |
| Tablet lubricant | Used in tablet formulations to reduce friction during tablet compression | Calcium stearate Magnesium stearate Mineral oil Stearic acid Zinc stearate |
| Tablet or capsule opaquant | Used to render a coating opaque. May be used alone or with a colorant | Titanium dioxide |
| Tablet polishing agent | Used to impart an attractive sheen to coated tablets | Carnauba wax White wax |
| Tonicity agent | Used to render solution similar in osmotic-dextrose characteristics to physiologic fluids, e.g., in ophthalmic, parenteral, and irrigation fluids | Sodium chloride |
| Vehicle | Carrying agent used in formulating a variety of liquids for oral and parenteral administration Generally, oral liquids are aqueous (e.g., syrups) or hydroalcoholic (e.g., elixirs). Solutions for intravenous use are aqueous, whereas intramuscular injections may be aqueous or oleaginous |
|
| Flavoured, sweetened | Content provided by http://thepharmapedia.com/ | Acacia syrup Aromatic syrup Aromatic elixir Cherry syrup Cocoa syrup Orange syrup Syrup |
| Oleaginous | Content provided by http://thepharmapedia.com/ | Corn oil Mineral oil Peanut oil Sesame oil |
| Viscosity-increasing agent | Used to render preparations more resistant to fl ow. Used in suspensions to deter sedimentation, in ophthalmic solutions to enhance contact time (e.g., methylcellulose), to thicken topical creams, etc. | Alginic acid Bentonite Carbomer Carboxymethylcellulose Sodium Methylcellulose Povidone Sodium alginate Tragacanth |
Mode of Action/Mechanism of action of Preservatives
Preservatives interfere with microbial growth, multiplication, and metabolism through one or more of the following mechanisms:
- Modify cation of cell membrane permeability and leakage of cell constituents (partial lysis)
- Lysis and cytoplasmic leakage
- Irreversible coagulation of cytoplasmic constituents (e.g., protein precipitation)
- Inhibition of cellular metabolisms, such as by interfering with enzyme systems or inhibition of cell wall synthesis
- Oxidation of cellular constituents
- Hydrolysis
| Name of Preservatives | Modes/Mechanism of action |
|---|---|
| Benzoic acid, boric acid, p-hydroxybenzoates | Denaturation of proteins |
| Phenols and chlorinated phenolic compounds | Lytic and denaturation action on cytoplasmic membranes and for chlorinated preservatives, also by oxidation of enzymes |
| Alcohols | Lytic and denaturation action on membranes |
| Quaternary compounds | Lytic action on membranes |
| Mercurials | Denaturation of enzymes by combining with thiol (-SH) groups) |
Download Previous Paper (Pharmacist, DI/DCO)
