Development and characterisation of semisolid systems to deliver propolis in the oral cavity

Pharmaceutical formulations containing poloxamer 407 (P407), Carbopol 934P (C934P) or gelatin (GELA), with ethanolic propolis extract (PE), were designed for the treatment of oral mucosal diseases. PE was produced and its quality was assessed by measuring its specific gravity, pH, weight of dry residue and total flavonoid content. Monopolymeric and binary polymeric formulations were prepared and their gelling temperature (Tsol/gel), pH, continuous flow rheology and mucoadhesion were studied. PE exhibited good quality and the formulations were easy to prepare and showed a wide range of consistency. Most of the formulations showed thermoresponsive behaviour and only those containing 15% P407, plus 0.20% C934P or 1.0 % GELA, displayed Tsol/gel suitable for application to the oral mucosa. Monopolymeric formulations, containing C934P or GELA, and binary formulations exhibited pseudoplastic flow and low degrees of thixotropy. Monopolymeric formulations containing P407 exhibited pseudoplastic flow and rheopexy. The mucoadhesive properties of the systems could not be assessed. Fragments of formulation were found to remain stuck to parts of the mucin disc, owing to cohesive failure of the samples and of the sample/mucin interface. The data obtained on these formulations indicate a potentially useful role in the treatment of oral mucosal diseases. Keywords: Propolis. Mucoadhesion. Poloxamer 407. Carbopol 934P. Gelatin. RESUMO Desenvolvimento e caracteriza o de sistemas semi-sólidos para libera o de própolis na cavidade bucal Formula es farmacêuticas contendo poloxamer 407 (P407), Carbopol 934P (C934P) ou gelatina (GELA), e extrato de própolis (EP) foram desenvolvidos para o tratamento de doen as da mucosa oral. EP foi produzido e sua qualidade foi avaliada quanto ao resíduo seco e ao teor de flavonóides totais. Formula es monopoliméricas e poliméricas binárias foram produzidas e a temperatura de gelifica o (Tsol/gel), o pH, a reologia, assim como a mucoades o das mesmas foram avaliados. O EP apresentou boa qualidade, as prepara es foram fáceis de produzir e apresentaram uma ampla varia o de consistência. A maioria das prepara es apresentou comportamento de resposta térmica e apenas as formula es contendo 15% P407 e 0,20% C934P ou 1,0% GELA apresentaram Tsol/gel adequada para a administra o na mucosa oral. Formula es monopoliméricas, contendo C934P ou GELA, e binárias exibiram comportamento de fluxo pseudoplástico e baixo grau de tixotropia. Formula es monopoliméricas de P407 exibiram fluxo pseudoplástico e reopexia. As propriedades mucoadesivas dos si