Excipients in tablets and other pharmaceutical formulations play varied roles depending on the intended purpose within the medicine, often necessitating distinct material properties to ensure effective results.
The roles of excipients in drugs include facilitating manufacturing, aiding breakdown and absorption in the body, and protecting the pharmaceutical ingredient from adverse conditions, whether inside or outside the body. Additionally, they add bulk to the product to enhance patient ease of use.
In many instances, not all excipients are required for tablets, as many can perform multiple roles. A classic case is starch, which can function as a diluent, binder, and disintegrant. Meanwhile, some excipients, such as sweeteners, are formulation-specific and may only be needed in chewable or sublingual tablets, rather than film-coated versions.
Typical Excipients in Tablet Manufacturing
- Diluents: Integral for adding volume or mass to tablets.
- Lubricants: Critical for minimizing friction between particles or between particles and metal surfaces.
- Glidants: Enhance the flow of tablet granules.
- Colorants: Provide the tablets with color for identification purposes.
- Flavorings: Used mainly in tablets that have direct oral contact, like chewable tablets.
- Sweeteners: Added primarily to chewable, dispersible, and sublingual tablets.
- Release-Modifying Agents: Employed to manage drug release in modified dosage forms.
- Coating Agents: Can be enteric or non-enteric, comprising of film formers and other components.
- Binders: Essential for binding powder into granules.
Excipients Classification
- Standard Excipients: These include both pharmacopoeia-listed and non-listed substances like lactose and magnesium stearate.
- Mixed Excipients: A physical blend of various excipients, like Opadry and Eudragit.
- Co-processed Excipients: A combination of excipients processed by methods like granulation.
Excipients Based on Origin
- Animal: Examples include lactose and gelatin.
- Vegetable: Includes starch and peppermint.
- Mineral: Includes talc and silica.
- Synthetic: Comprises substances like saccharin and lactic acid.
Disintegrants in Tablet Formulations
These essential components help the tablet disintegrate into smaller fragments for efficient drug dissolution. Common disintegrants include microcrystalline cellulose and starch.
Commonly Used Disintegrants
- Crospovidone: Utilized in doses around 2–5%.
- Croscarmellose Sodium: Typically used in concentrations up to 5%.
Role of Excipients in Pharmaceutical Formulation
Pharmaceutical formulations always include both active pharmaceutical ingredients and excipients. These excipients, while therapeutically inactive, perform critical roles in enhancing the properties, stability, and usability of the final product.
(The author specializes in chemicals and pharmaceuticals)