A tablet is a pharmaceutical dosage form. It contains of a combination of active substances and excipients, generally in powder form, passed are compacted into a solid dose.
- Diluents, binders or granulating agents, glidents and lubricants to ensure efficient tableting;
- Disintegrates: to promote tablet break up in the digestive tract;
- Sweeteners or flavours: to enhance the taste;
- Polymer coating: it is applied to make the tablet smoother and easier to swallow, to control the release rate of the active ingredient, to make it more resistant to the environment.
There are three methods by which tablets are manufactured;
- Wet granulation
- Dry granulation
- Direct compression
Manufacturing process depends on many factors, including the compression properties of the therapeutic agents, the particle size of the therapeutic agent, excipients and the chemical stability of the therapeutic agent throughout the producing method.
- It is most commonly used method for the manufacturing of tablets.
- Water is frequently used as the granulation fluid (and heat is employed to dry the formed granules), it is important to ensure that the therapeutic agent is chemically stable during the granulation process.
- The wet granulation exhibit sufficient mechanical properties to be subsequently exposed to other unit operations, Eg: film coating.
- Tablet quality is directly affected by the choice and concentration of binder and the type and volume of granulation fluid. Due to the number of unit operations to the required, the manufacture of tablets by wet granulation is not as efficient as other methods. Eg: direct compression.
- When tablet ingredients are sensitive to moisture and unable to withstand elevated temperature during drying and when the tablet ingredient have insufficient cohesive properties, slugging may be used to form granules.
- This technique is used in preparation of aspirin, aspirin combination, and acetophenetidin.
Excipients used in this method:
- Diluents/ filler: anhydrous lactose/ lactose monohydrate, starch, dibasic calcium phosphate, and MCC
- Disintegrants: Starch, MCC, Sodium starch glycolate, Croscarmellose sodium, Crospovidone.
- Lubricants: Stearates (Mg. stearate, steric acid), Glyceryl fatty acid esters, polyoxyethylene stearates, SLS.
- Glidants: Talc, Colloidal silicon dioxide.
- Miscellaneous Excipients: Colours, sweetening agents, etc.
Advantages & Disadvantages:
- This technique popularity has decreased in recent years, having been superseded by direct compression.
- However both slugging and roller compaction are still employed in tablet manufacture.
- Wet granulation and dry granulation methods having series of unit operations, both time consuming and potentially costly.
- Potentially more attractive option for the manufacture of tablets involves powder mixing and subsequent compression of the powder mix, thereby obviating the need for granulation. This process is called direct compression.
- The mechanism of particle-particle interactions in tablets produced by direct compression are similar to those operative in tablets produced by dry granulation and roller compaction.
Manufacture of Tablets Steps:
- Mixing of the therapeutic agents with the excipients
- Granulation of the mixed powders (this is not performed in direct compression)
- Mixing of the powders or granules with other excipients (mostly lubricants)
- Compression into tablets
- The details of each of these steps will vary depending on the manufacturing method used.
The selection of a tableting method depends on variety of things, including the chemical properties of the API similarly because the desired mechanical options of the finished tablets. Whereas heat-based granulation techniques are unsuitable for APIs with temperature sensitivities, and liquid- or foam-based processes may be harmful to water-sensitive APIs, these methods can provide many of the advantages of dry granulation, without the fragility of a dry-compressed tablet product.
We at KERONE have a team of experts to help you with your need for different methods of tablet manufacturing in various products range from our wide experience