Matrix Release from Tablets Prepared with Aqueous Dispersion of an Acrylate Methacrylate (a Water -Insoluble) Copolymer as Binder

ABSTRACT

Purpose: To investigate the binder effect of aqueous dispersions of acrylate methacrylates (AMA) copolymer with a view to obtaining matrix (non-disintegrating) tablets with a retard release property. Methods: Aqueous dispersions of AMA (1-15w/v) were formed by a coacervation procedure using ethanol (10 ml) as solvent and water (90 ml) as non-solvent for the copolymer. The aqueous dispersions were used to wet-mass the drug (paracetamol) powder. Resulting granules were compressed to 500 mg tablets using a single punch machine. The tablets were subjected to hardness; friability; disintegration and dissolution tests. Results: The granules formed hard tablets (tensile strength 1 - 2.0 MNm-2) with low friability decreasing from 2 to 1as the AMA binder concentration increased from 0.75 to 11.25w/w. The tablets failed to disintegrate in 3 hr. Drug release generally followed the Higuchi square root of time kinetic (R2 = 0.95). The AMA binder markedly retarded drug release as reflected by the sharp decrease in the dissolution rate constant from 30 min-2 (AMA; 0.75w/w) to 9 min-2 (AMA; 11.25w/w). Conclusion: The AMA dispersion is an effective binder; producing matrix tablets with a retard release property controlled by the binder content in the tablets