Efeito da massa molar do acetobutirato de celulose e da adi o de poli(3-hidroxibutirato) sobre as características das microesferas e o prolongamento da libera o do cetoprofeno

No presente trabalho, foram elaboradas microesferas de acetobutirato de celulose (ABC) contendo cetoprofeno com o objetivo de prolongar a libera o do fármaco. Utilizou-se a técnica de emuls o e evapora o do solvente, variando-se os seguintes parametros: massa molar do ABC e a adi o ou n o de poli(3-hidroxibutirato) (PHB), segundo um planejamento fatorial 22. Maiores eficiências de encapsula o do cetoprofeno foram obtidas quando utilizado ABC com maior massa molar e a adi o do PHB levou a uma diminui o do percentual de fármaco encapsulado. Todas as formula es originaram partículas esféricas, com cristais de fármacos aderidos à superfície externa e matriz polimérica porosa quando adicionado o PHB. Os perfis de libera o in vitro indicaram que o aumento da massa molar do ABC levou a uma diminui o do percentual de fármaco inicialmente liberado e a um prolongamento de sua libera o. Por outro lado, a adi o do PHB acelerou a libera o do cetoprofeno a partir das microesferas. Palavras-chave: Microesferas. Cetoprofeno. Prepara es de libera o retardada. ABSTRACT Effects of cellulose acetate butyrate molar weight and addition of poly(3-hydroxybutyrate) on microsphere morphology and ketoprofen prolonged release In the present study, cellulose acetate butyrate (CAB) microspheres containing ketoprofen were produced, with the objective of prolonging its release. The emulsion/solvent evaporation technique was used to make the spheres, varying the parameters (1) CAB molecular weight and (2) addition or not of poly(3-hydroxybutyrate) [PHB], to optimize drug encapsulation, following a 22 factorial design. Higher ketoprofen encapsulation efficiency was obtained when higher molecular weight CAB was used, while the addition of PHB caused a decrease in the percentage of encapsulated drug. All the preparations produced spherical particles, with drug crystals adhering to the external surface, and a porous polymer matrix when PHB was used. The in vitro release profiles indicated that lowering the CAB molecular weight led to a decrease in the drug initially released and a prolonged release. On the other hand, the addition of PHB accelerated the release of the ketoprofen from the microspheres. Keywords: microspheres. Ketoprofen. Delayed-release preparations.