The direct compression method is the shortest method used in the pharmaceutical industries for the manufacturing of tablets. It is a very simple method and less equipment and labour is required. However, all products can not be compressed by direct compression because it has many limitations.
As the name indicates that direct compression involves directly the compression of powders without the production of granules.
Direct Compression Method is used for those products which have good compressibility properties.
It is used for low dose or potent products.
It is used for those products which have good flow properties or flow is improved by using granular type excipients which are easily compressed e.g coarse grades of microcrystalline cellulose and Spray-dried Lactose instead of simple lactose.
Low dose and medium dose Products are good for direct compression method and large dose products are not reasonable because tablet weight is increased too much. In Direct compression, we simply compress the powders without forming granules or slugs, so it is economical and time-saving because the equipment which is used for manufacturing of granules in wet or dry granulation is not required for direct comparison.
Following steps are involved for Direct Compression,
Weighing of ingredients
Weigh all the ingredients according to BMR.
Sieving of ingredients
Sieve all ingredients through a proper mesh.
Mix API and excipients in a reasonable mixer and mix lubricants at the end.
Now the mixed powder is removed from the mixer and is compressed by using suitable tooling on compression machine.
Merits of Direct compression
- Short time is required to complete the process so efficiency is enhanced.
- Less labour is required.
- Less equipment utilization.
- Cleaning time is reduced as compared to wet granulation and dry granulation.
De-Merits of Direct compression
- All products can not be compressed by direct compression method.
- In case of high dose products final weight of tablet become too high so this method is not suitable for high dose.
- Powders result in compression related problems like flow problem, weight variation.
- Granular type excipients are used in dry granulation which are costly.