Overview of wet granulation drying and granulation processes in wet granulators

Overview of wet granulation drying and granulation processes in wet granulators

The wet granulation technology of the wet granulator is to add a binder or a wetting agent to the pharmaceutical powder to make a soft material, sieving to make wet granules, and drying the wet granules and then granulating them. The granules made by the wet method have the advantages of good surface modification, beautiful appearance, strong abrasion resistance, good compression formability, etc., and are most widely used in the pharmaceutical industry.

The main mechanism of wet granulation:

First, the liquid in the binder wets the surface of the drug powder, causing adhesion between the particles, and then made into particles of a certain shape and size under the action of the liquid bridging and external mechanical force. After drying, it is finally solid. Consolidation in the form of a bridge.

1. Wet granule drying of wet granulator:

筛 The wet granules produced by sieving should be dried immediately to avoid agglomeration or deformation under pressure (the stainless steel tray can be used to spread the prepared wet granules and spread out from time to time to solve the problem of wet granule storage agglomeration and deformation).

Drying temperature: It depends on the nature of the raw materials, generally 50-60 ℃; for some drugs that are stable to humidity and heat, the drying temperature can be appropriately increased to 80-100 ℃.

Drying degree: Control by measuring water content. Granules require that the moisture content of the granules not exceed 2%; the tablet granules retain appropriate moisture according to the difference of each specific variety, generally about 3%.

Drying equipment: Commonly used are box-type (such as drying room, oven) drying, boiling drying, microwave drying or far infrared drying and other heating and drying equipment.

2. Whole grain process:

After the wet granules are dried, they need to be sieved and sieved to break up the agglomerated granules to meet the particle size requirements of the granules or the tablet compression requirements.

(1) Granules: A sieve with a smaller mesh size than 10 mesh (sieve 1) can be used to make the granules that can not pass through the sieve. The lower limit of particle size specification, after passing through 60 mesh or 80 mesh (No. 5 sieve), classify and take particles between 10-80 mesh;

(2) Tablets: Granules can be used with larger sieve meshes than those used to make wet granules.