Disintegrating agents mechanism action

Botzolakis, J.E. Augsburger, L.L. Disintegrating agents in hard-gelatin capsules. Part I mechanism of action. Drug Dev. Ind. Pharm. 1988, 14, 29-41. 

The mechanism of action of disintegrating agents has been the subject of some debate. Some substances such as starch swell when they come into contact with water, and disruption of the tablet structure has been attributed to this. However, other effective disintegrants do not swell in this way, and are believed to act by providing a network of hydrophilic pathways inside the tablet through which water can diffuse. Irrespective of the precise mechanism of disintegration, it is clear that water uptake into the tablet must be the first step in the disintegration process. ... 

Patel NR, Hopponen RE. Mechanism of action of starch as a disintegrating agent in aspirin tablets./ Pharm Sci 1966 55 1065-1068. 

Crospovidone (Polyplasdone XL) swells sparingly in water. Its mechanism of action is based on capillary forces, which allow for fast penetration of water into the tablet. In tablets with a high content of highly soluble compounds, such as anhydrous beta-lactose, it is more effective than both other super-disintegrating agents. 

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