this should be correlated with the dissolution rate of the api and surface tension

The main aim of delivery through any dosage form is the delivery of API. Tablets are mainly formulated via granulation technology like direct compression, wet granulation and dry granulation followed by compression. The compression impacts the drug release from granules. Larger the compression force, higher are the chances of the retard of drug release from granules. The uniformity of dispersion test via mesh 22 ensures that the tablet disintegrates and breaks down to granules passable through the 22 mesh size such that all tablets passing this test will show almost uniform breakdown to granules to give a predictabe and desirable drug release.

Dear Harshita Madam,

Disintegration test is carried out through 10 mesh as specified in USP, whereas Dispersion is through 22 mesh. Can you clarify the reason behind that??

Uniformity of Dispersion test is generally meant for *Dispersible Tablets*, which are uncoated or film-coated tablets intended to be dispersed in water before administration giving a homogeneous dispersion.

In *Uniformity of Dispersion test*, 2 Tablets are placed in 100 ml of water & stirred gently until completely dispersed. A *smooth dispersion* should be obtained which should be passed through 22# (710 microns).

Here smooth dispersion (less than 750 micron) is must *to promote acceptable mouth feel without producing any type of grittiness in the oral cavity* which may compromise patient acceptance compliance.

Moreover, as the PSD of dispersed particle reduced, it will be readily available for absorption through mucosa.

(In *other types of IR Tablets*, Disintegration test is generally performed to ensure only disintegration of tablets into granules through 10# (2000um=2mm)

Because these tablets are meant to be swallowed with water which will be directly reach into stomach where it is meant to be disintegrated & dissolved.)