A pharmaceutical additive or an excipient is a substance that mixed with an active pharmaceutical ingredient for a specific purpose.
I will go through the most common types with examples:
1. Antioxidant :
It is an agent that prevent the oxidation process to the pharmaceutical preparation. Thus, avoid its deterioration.
|Type||Water Soluble||Lipid Soluble|
Simply, related to humidity, so the basic function is to keep the preparation wet and avoid dryness like in ointment and creams.
- Propylene glycol.
3. Stiffening Agents:
Are used to increase the thickness of the pharmaceutical preparations as in an ointments.
Examples : White Wax, Yellow Wax and Paraffin.
4. Suspending Agents:
Are used to increase the viscosity of the vehicle to reduce the rate of sedimentation. Usually the drug is not soluble in the vehicle and a suspending agent is required. Drugs of that type often require the statement “Shake before Use”.
Examples : Agar, Gum tragacanth and Bentonite.
5. Flavoring Agents:
Are used to enhance the pharmaceutical preparation taste and odour.
Examples : usually volatile oils like Anise oil, cinnamon oil, Cocoa, Menthol and strawberry flavors.
6. Coloring Agents (Colorant):
Are used to add a color to liquid preparations.
Examples : Caramel.
7. Sequestering Agents (Chelating Agents):
Agents that are used to form stable complex with metals, they are used as stabilizers in cases of instability caused by metals especially in liquid pharmaceutical preparations.
Examples : EDTA ( Ethyele Diamine tetra acetic acid).
8. Anti-Adherent agents:
Usually used in tablet preparations to avoid the sticking of tablet ingredients.
Examples : Talc & Silicon Dioxide.
9. Polishing agents:
Usually used in tablet preparations to be more attractive.
Examples : White Wax & Carnauba Wax.
10. Emulsifying agents (emulgent):
They are agents that are soluble in both Fat & Water. have hydrophilic and lipophilic characters and used to enhance the stability of the emulsion avoiding the separation between the two phases. They are also known as surfactant or surface active agents.
Tweens and spans