微晶纖維素之物理性修飾

在直接壓錠 (direct compression) 方面上，微晶纖維素 (M icrocrystalline cellulose,MCC) 由於具備良好壓錠性 (Comp actibility) 性質的條件，因此為市面上最受歡迎的直接壓錠 賦形劑。微晶纖維素其成錠機轉主要是以塑性形變 (plastic d eformation) 為主。同時顆粒的形狀呈不規則狀提供顆粒與顆 粒之間以機械連結 (mechanical interlocking) 的結合方式成 錠，然而，不規則的顆粒又會造成粉末的流動性差。 有鑑於此，本實驗希望藉由 beta-cyclodextrin 與 MCC slur ry 共同乾燥製備來修飾其基本物性性質以及了解其壓錠性 質。由實驗結果顯示， MCC slurry 藉由 beta-cyclodextrin 共製明 顯改善其流動性，其中以顆粒大小為 61~149mm( 處方 2L ~ 4 L) 最明顯。其原因可能是由於共製後的顆粒形狀呈較規則所 造成。此外，其錠片的硬度以及崩散性隨著 beta-cyclodextrin 量 比例增加也有明顯較佳的效果。在壓錠性質方面利用 Heckel Plot 公式評估發現 L 及 S 處方隨著 beta-CD 的量增加，其 Yield Pr essure 都有增加的現象，而且藉由其錠片表面及橫切面之 SE M 圖顯示，可推測 MCC 與 beta-CD 共製後，其成錠機轉仍以塑性 形變方式進行。

Physical Modification of Microcrystalline Cellulose

Microcrystalline cellulose (MCC) is a material that i s very popularly used as an excipient in the production of tablets as a result that it exhibits the best compactibility i n the direct compression. MCC powders are known to for m tablets mainly through plastic deformation. However, the irregularly shaped particles of MCC, which might improve the tensile strength of tablets as a result of mechanical int erlocking bonding, is responsible for its poor flowability of smaller size grade of MCC. In an attempt to improve the flowability of MCC w ithout sacrificing its compactibility, MCC was codried with various amount of beta-cyclodextrin (beta-CD). The physical ch aracters of the resulting powder and tablets were examined and compared. The results showed that the modification o f MCC by codrying with beta-CD significantly improved the flowability of original powder of MCC. This could due to the improved rounded shape of codrying particles. It was f urther confirmed to be true by SEM. Moreover, the compa ctibility and disintegration of tablets produced with the cod rying powders were much better than those using MCC alo ne and even better than various grades of MCC commercia lly available. Data from the Heckel plot indicated that the yield pressure for two different size fractions (61-149 mm and 37-61 mm) increased with the increase of the added a mount of beta-CD in the formulations. By SEM examinations on the surface and cross-section of tablets, all demonstrat ed that codried prodcuts of MCC tablets still through plasti c deformation.