Granules are agglomerates of powders. Depending upon the application, various granules of different size can be prepared. The usual size ranges of granules are in the range of 4–12 sieve.

Advantages of Granules

1. They flow better than powders. The easy flow characteristics are important in supplying drug materials from the hopper or feeding container into the die cavities of the tablet compression machine. For this reason, powder mixtures are usually granulated if they are intended to be compressed into tablets. Granules also eliminate or control dust.
2. They increase compressibility.
3. They have smaller surface area than a comparable volume of powders. This makes granules more stable physically and chemically than the corresponding powders.
4. They are more easily wetted by a solvent than certain powders, so that granules are also preferred in making solutions.Example: Ampicillin is unstable in aqueous solution, so it is usually prepared as granules and reconstituted with boiled and cooled water just prior to administration. The granules also contain colorants, flavorants and other pharmaceutical ingredients. So the resulting solution or suspension has all the desired medicinal and pharmaceutical features of a liquid pharmaceutical.
5. They produce particle-size uniformity and thus content uniformity.