Disintegrating efficiency of croscarmellose sodium in a direct compression formulation

The efficiency of croscarmellose sodium (Ac-Di-Sol(R)) in a direct compression formulation containing a poorly water soluble drug (albumin tanate) at high dosage was investigated. An experimental design with two variables, applied pressure and concentration of Ac-Di-Sol(R), allowed the;evaluation of microstructural, mechanical and disintegration properties of the tablets. Tablet properties evaluated were affected by both variables, while compression parameters were essentially dependent on applied pressure. The disintegration process was correlated with the densification behaviour, analysed by means of Heckel plots and force-displacement curves, and tablet microstructure, measured by using a mercury porosimeter. The shortest disintegration time was found for mixtures more prone to plastic deformation and densification at same level of applied pressure. These mixtures also revealed a finer pore structure. However, mixtures with higher yield pressures (i.e. less prone to plastic deformation) showed longer disintegration times and coarse pore structure. The different rearrangement of disintegrant particles in powder mixture is suggested tb explain the dominant effect of the disintegrant bonding mechanism presented at a given mixture composition. According to our results, consolidation mechanism and microstructure analysis should be performed while optimizing disintegration response in tablets formulated with a disintegrant mainly acting by swelling mechanism. (C) 1997 Elsevier Science B.V.