Lionzo Maria I Z, Ré Maria I, Guterres Silvia S, Pohlmann Adriana R
Faculdade de Farmácia, Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
J Microencapsul. 2007 Mar;24(2):175-86. doi: 10.1080/02652040701233556.
The objective of this work was to verify the influence of the poly(epsilon-caprolactone) PCL concentration in poly(hydroxybutyrate-co-hydroxyvalerate) P(HBHV)/PCL microparticles, prepared by an emulsion/solvent evaporation process, on the release behavior of a drug. Differential Scanning Calorimetry analyses demonstrated that the preparation process increased the crystallite heterogeneity for the P(HBHV) in the particles. The drug caused an increase in the glass transition of the P(HBHV) in the microparticles. Dexamethasone acetate-loaded microparticles demonstrated drug sustained releases (up to 250 h), which profiles fit the biexponential model. The release of dexamethasone acetate caused an increase in the surface area of the microparticles. The kinetic constants of the sustained phase increased with the augmentation of the PCL content in the blend. The drug release mechanism was dependent on the presence of PCL in the microparticles. A Fickian release was determined for the microparticles prepared exclusively with P(HBHV), while non-Fickian release behaviors were found for the P(HBHV)/PCL microparticles.
本研究的目的是验证通过乳液/溶剂蒸发法制备的聚（3-羟基丁酸酯-共-3-羟基戊酸酯）P(HBHV)/聚己内酯PCL微粒中聚己内酯PCL浓度对药物释放行为的影响。差示扫描量热法分析表明，制备过程增加了微粒中P(HBHV)的微晶异质性。药物导致微粒中P(HBHV)的玻璃化转变温度升高。载有醋酸地塞米松的微粒表现出药物缓释（长达250小时），其释放曲线符合双指数模型。醋酸地塞米松的释放导致微粒表面积增加。持续释放阶段的动力学常数随着共混物中PCL含量的增加而增大。药物释放机制取决于微粒中PCL的存在。仅由P(HBHV)制备的微粒呈现菲克扩散释放，而P(HBHV)/PCL微粒则呈现非菲克扩散释放行为。
