J. Conceição^1,, M. Estanqueiro¹, M. H. Amaral¹, P. Lobão¹, P. Costa¹, J. M. Sousa Lobo¹

The aim of this study was to develop and characterize buccal bilayer tablets containing ibuprofen microparticles, prepared through emulsion/chilling method, to obtain a sustained release. In this way, three formulations of bilayer tablets containing three bioadhesive polymers, namely Noveon^® AA-1 Polycarbophil USP, Carbopol^® 974 and Carbopol^® 980 were prepared. Weight uniformity, friability, hardness and in vitro drug release studies, by two different methods, were evaluated in the manufactured tablets. The calculation of similarity factor (f₂) was also carried out. In addition, three gels (0.5%, w/w) with the same polymers were prepared and textural analysis (firmness and adhesiveness) were assessed in comparison with the bioadhesive layer of tablets. Buccal bilayer tablets with suitable physical properties (weight uniformity, hardness and friability) were produced. In vitro dissolution tests, performed during 8 hours, have demonstrated a sustained release of ibuprofen (maximum drug released: 30.0 - 45.1%). According to f₂, both dissolution methods and the three studied polymers showed similar dissolution profiles (f₂ > 50). Tablets containing Carbopol^® 974 showed higher values of firmness and adhesiveness after 6 h of hydration in phosphate buffer pH 7.4. On the other hand, it was not possible to verify a relationship between the textural parameters of the gels and the bioadhesive layer of tablets containing the same polymers.

Buccal Bilayer Tablets, Bioadhesive Polymers, Microparticles, Ibuprofen, Sustained Release