INFLUENCE OF THE DISINTEGRANT ON THE DRUG PERCOLATION-THRESHOLD IN TABLETS

Previous papers studied ternary tablets containing different concentra tions of polyvinylpyrrolidone cross-link (PVP-CL) as disintegrant. The drug percolation threshold, p(cl), for these tablets was estimated to fall in the range 0.26-0.31 of total porosity. The aim of the present paper is to study if the presence of the disintegrant agent (PVP-CL) in these tablets, exerts an important effect on the drug percolation t hreshold obtained. For this purpose, binary tablets containing the sam e model drug and excipient have been prepared in identical technologic al conditions. The drug percolation threshold in these matrix tablets has been calculated following the method of Bonny and Leuenberger (5). The results obtained show no significant difference between p(cl) in the binary matrix tablets and the drug percolation threshold found in the tablets containing the disintegrant agent. This result supposes a stimulus for the application of the principles of percolation theory t o a great number of pharmaceutical systems containing disintegrant age nts or substances which cause a strong change in its release behavior.