Picker K M
Martin-Luther-University Halle-Wittenberg, Department of Pharmacy, Halle/Saale, Germany.
Drug Dev Ind Pharm. 1999 Mar;25(3):329-37. doi: 10.1081/ddc-100102178.
Carrageenans can be used as excipients for controlled-release tablets. The aim of this study was to determine their compaction and consolidation behavior to prove their usefulness for tableting. The Carr indices of the three carrangeenans, two kappa-carrageenans(Gelcarin GP-812 NF and GP-911 NF) and one tau-carrageenan (Gelcarin GP-379 NF), indicate that the materials are free flowing. They are polymers in the rubbery state. Their glass transition-temperature is about 0 degree C analyzed by differential scanning calorimetry (DSC). The powders were analyzed regarding their compression behavior using an eccentric tableting machine. From data obtained during one compaction cycle, porosity-pressure and pressure-time plots were made. Compaction behavior is evaluated by fitting the pressure-time function to the pressure-time plot and by fitting the Heckel function to the porosity-pressure plot. The polymers show "viscoelastic" tableting behavior. Several additional tableting parameters were analyzed for strengthening the results obtained, namely, maximum work, maximum power, and the time between maximum upper punch force and maximum displacement of the upper punch. The crushing strength of the tablets is high; therefore, the carrageenans are able to form strong compacts. However, they remain in the rubbery state, as shown by thermomechanical analysis. In addition, elastic recovery is regarded at several times after ejection. Finally, after 10 days, it is about 30% as determined from the minimum of tablet height during the compression cycle. These results indicate that the carrageenans are suitable tableting excipients for controlled-release tablets. They show good compactibility and good consolidation behavior. Strong compacts with a high elastic recovery are formed; this means that the materials are able to embed drugs softly. Only a little stress and strain remains in the tablet. All three carrageenans show similar tableting behavior, and a flexible dosage form design is possible.
角叉菜胶可用作控释片剂的辅料。本研究的目的是确定其压缩和固结行为，以证明其在压片方面的实用性。三种角叉菜胶，即两种κ-角叉菜胶（Gelcarin GP - 812 NF和GP - 911 NF）和一种τ-角叉菜胶（Gelcarin GP - 379 NF）的卡尔指数表明这些材料具有良好的流动性。它们是处于橡胶态的聚合物。通过差示扫描量热法（DSC）分析，其玻璃化转变温度约为0℃。使用偏心压片机分析了这些粉末的压缩行为。根据在一个压缩循环中获得的数据，绘制了孔隙率-压力和压力-时间曲线。通过将压力-时间函数拟合到压力-时间曲线以及将赫克尔函数拟合到孔隙率-压力曲线来评估压缩行为。这些聚合物表现出“粘弹性”压片行为。为了强化所得结果，还分析了几个额外的压片参数，即最大功、最大功率以及最大上冲力与上冲最大位移之间的时间。片剂的抗压强度很高；因此，角叉菜胶能够形成坚固的压块。然而，如热机械分析所示，它们仍处于橡胶态。此外，在弹出后多次观察弹性恢复情况。最后，10天后，从压缩循环中片剂高度的最小值测定，弹性恢复约为30%。这些结果表明，角叉菜胶是适用于控释片剂的压片辅料。它们表现出良好的可压性和固结行为。形成了具有高弹性恢复的坚固压块；这意味着这些材料能够轻柔地包埋药物。片剂中仅残留少量应力和应变。所有三种角叉菜胶都表现出相似的压片行为，并且可以进行灵活的剂型设计。
