Wet granulation is a process of forming granules from powder forms by binding them together using adhesives, which are usually in the form of a solution or suspension in a suitable liquid. The liquid is added to the powder under the influence of an impeller, screws, or air, which produces bonding between the primary powder particles to produce wet granules. The final step of the wet granulation process is the evaporation of the solution, which leaves the original powder particles bound together with the adhesive binder.

Wet granulation is a major unit operation in the production of pharmaceuticals as solid dosage oral formulations. It is the oldest and most popular technique in the pharmaceutical industry. The advantages of wet granulation include better uniformity, perfect shapes, masking of tabulation deficiencies, and speeding up the dissolution speed of drugs with poor dissolution rates.

Some key aspects of the wet granulation process include:

• Excipients are the extra materials in a drug apart from the active ingredient.
• The granulation liquid should be non-toxic and is preferably water, although various other solvents may be considered, such as propan-2-ol and ethanol.
• The granulation liquid may be used alone or with dissolved binders (glue) .
• The process of wet granulation can be very simple or complex depending on the characteristics of the initial powders and the final objective.
• Wet granulation is traditionally a batch process in the pharmaceutical production, but the batch type wet granulations are foreseen to be replaced more and more by continuous wet granulation in the pharmaceutical industry in the future.