Kawashima Y, Niwa T, Takeuchi H, Hino T, Ito Y
Gifu Pharmaceutical University, Japan.
Chem Pharm Bull (Tokyo). 1992 Jan;40(1):196-201. doi: 10.1248/cpb.40.196.
Prolonged-release spherical micro-matrices of ibuprofen with Eudragit RS were prepared using a novel emulsion-solvent diffusion method. Those particles were termed "microspheres" due to their characteristic sponge-like texture and unique dissolution and compression properties unlike conventional microcapsules or microspheres. The internal porosity of microspheres could be easily controlled by changing the concentration of the drug and the polymer in the emulsion droplet (ethanol). With lower concentration of ibuprofen in the ethanol, the resultant microspheres had a higher porosity, about 50%. The drug release rate from the microspheres was interpreted by the Higuchi model of spherical matrices, which depended only on their internal porosity of the microspheres when size distribution and drug content were the same. The tortuosities in the microspheres were found to be almost constant (3-4) irrespective of porosity, suggesting the same internal texture. Microsphere compressibility was much improved over the physical mixture of the drug and polymer owing to the plastic deformation of their sponge-like structure. The more porous microspheres produced stronger tablets [corrected].
采用新型乳液-溶剂扩散法制备了含欧巴代RS的布洛芬缓释球形微基质。由于其具有类似海绵的质地以及与传统微胶囊或微球不同的独特溶解和压缩特性，这些颗粒被称为“微球”。通过改变乳液滴（乙醇）中药物和聚合物的浓度，可以轻松控制微球的内部孔隙率。乙醇中布洛芬浓度较低时，所得微球具有较高的孔隙率，约为50%。微球的药物释放速率由球形基质的Higuchi模型解释，当粒径分布和药物含量相同时，该模型仅取决于微球的内部孔隙率。无论孔隙率如何，微球中的曲折度几乎恒定（3-4），表明内部结构相同。由于其海绵状结构的塑性变形，微球的可压缩性比药物与聚合物的物理混合物有了很大提高。孔隙率更高的微球制成的片剂强度更大[已修正]。
