压缩方程评价不同孔体积微丸的压缩特性

采用Kawakita压缩方程评价不同孔体积微丸的压缩特性，为微丸压片工艺的研究提供科学依据。采用不同体积比例的乙醇/水混合液作黏合剂，以微晶纤维素 (MCC)、磷酸二氢钙 (DCP) /MCC (4∶1, w/w)、乳糖 (Lac) /MCC (4∶1) 为填充剂，挤出-滚圆工艺分别制备不同孔体积微丸。以Kawakita压缩方程评价前述微丸的压缩特性，结果表明高孔体积MCC微丸可压性最好，而3种孔体积的DCP/MCC (4∶1) 微丸和Lac/MCC (4∶1) 微丸没有显著差别，这与微丸压缩过程中发生的压缩机制有关，MCC微丸主要发生了塑性变形, 另外两类辅料制成的微丸则主要发生破碎，扫描电镜图直观说明了这一现象。研究结果提示微丸压片工艺发生的机制复杂, 选用不同辅料制备微丸的压缩特性各异，而高孔体积MCC微丸和不同孔体积的DCP/MCC微丸和Lac/MCC微丸可作为微丸压片过程中的缓冲颗粒，以保护含药微丸使之在压片过程中保持原有的形态和释放行为。

Evaluation with compression equations of compression behavior of pellets with different intragranular pore volumes

Microcrystalline cellulose (MCC), calcium phosphate (DCP)/MCC (4∶1, w/w) and lactose (Lac)/MCC (4∶1) pellets with different intragranular porosity were prepared in an extrusion-spheronizator and three volume ratios of ethanol/water were used as binder agents to prepare pellets.  The compression behaviors of these pellets with different intragranular pore volume were evaluated with the parameters of Kawakita model.  The results showed that high pore volume of pellets made up of MCC had the best compressibility and low pore volume of pellets had a poor compactibility.  However, the compressibility of different porosity of pellets made up of DCP/MCC (4∶1) or Lac/MCC (4∶1) was good, but they were not significantly different.  The reason might be the main compression mechanism of high porosity of MCC pellets was plastic deformation and that of DCP/MCC pellets or Lac/MCC pellets was not plastic deformation but fragmentation.  These results can be  observed directly by the SEM photographs.  According to these results, the conclusion could be drawn that high porosity MCC pellets and different porosity DCP/MCC pellets and Lac/MCC pellets can be used as cushion granules to maintain the original shape and release characteristics of drug pellets when pellets were tabletted.