Pan granulation mechanism: The mechanism of granulation process mainly divided into Dry Granulation and Wet Granulation. The formation of granules by Dry Granulation and Wet Granulation is totally different.
The conversion of powder to dry granules bed is totally different based of the machine used in granulation process, same as for Wet Granulation Process. The method of formation of granules in pan granulation mechanism can be described in different ways-
Nucleation
In the presence of liquid/water a liquid bridges form an intact mass due to particle contact and adhesion which act as nuclei for further growth of granules. Presence of liquid, powder go through the stages act as nuclei.
Transition
The nuclei can be formed in two ways-One way is- where a single particle can be added to the nuclei and another is two nuclei can be add themselves and the resulted two nuclei reshape by the agitation of podwer bed.
Ball Growth
The resulting powder will grow in time to time and size increase of this spherical granules look like a ball. The ball growth process produces large granules, some this is too much large to use in pharmaceutical purposes. The spheronizing equipment like planetary mixer facilitate some degree of ball growth activities.
The ball growth process can be divided into four classes, stated here-
Coalescence
Two or more granules join together to form a larger granule.
Breakage
Granules are fragmented in to several parts and this parts joint in to another granules and form a layer over the existing granules.
Abrasion Transfer
When granules beds are facing agitation then attrition occur to the materials from granules, then this abraded materials attached/adhere to the other granules increase their size.
Layering
When we add one separate amount of powder to a granules bed then this powder adhere/attached to the granules form a granules layer over the surface and increase the granule size.