Obeidat Wasfy M, Obaidat Ihab M
Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan.
J Microencapsul. 2007 May;24(3):263-73. doi: 10.1080/02652040701233648.
The dispersion/incorporation of Eudragit S100 powder as a filler in cellulose acetate butyrate (CAB-551-0.01) microsphere containing theophylline was investigated as a means of controlling drug release. Microspheres of CAB-551-0.01 of different polymer solution concentrations/viscosities were prepared (preparations Z(0), Z(A), Z(B) and Z(C)) and evaluated and compared to microspheres of a constant concentration of CAB-551-0.01 containing different amounts of Eudragit S100 powder as a filler (preparations X(A), X(B) and X(C)). The organic solvent acetonitrile used was capable of dissolving the matrix former CAB-551-0.01 only but not Eudragit S100 powder in the emulsion-solvent evaporation method. The CAB-551-0.01 concentration in Z(A), Z(B) and Z(C) was equal to the total polymer concentration (CAB-551-0.01 and Eudragit S100 powder) in X(A), X(B) and X(C), respectively. Scanning electron microscopy (SEM) was used to identify microspheres shape and morphology. In vitro dissolution studies were carried out on the microspheres at 37 degrees C (+/-0.5 degrees C) at two successive different pH media (1.2 +/- 0.2 for 2 h and 6.5 +/- 0.2 for 10 h). Z preparations exhibited low rates of drug release in the acidic and the slightly neutral media. On the other hand, X preparations showed an initial rapid release in the acidic medium followed by a decrease in the release rate at the early stage of dissolution in the slightly neutral pH which could be due to some relaxation and gelation of Eudragit S100 powder to form a gel network before it dissolves completely allowing the remained drug to be released.
研究了将Eudragit S100粉末作为填充剂分散/掺入含茶碱的醋酸丁酸纤维素（CAB - 551 - 0.01）微球中作为控制药物释放的一种方法。制备了不同聚合物溶液浓度/粘度的CAB - 551 - 0.01微球（制剂Z(0)、Z(A)、Z(B)和Z(C)），并与含有不同量Eudragit S100粉末作为填充剂的恒定浓度CAB - 551 - 0.01微球（制剂X(A)、X(B)和X(C)）进行评估和比较。在乳液-溶剂蒸发法中，所用的有机溶剂乙腈仅能溶解基质形成剂CAB - 551 - 0.01，而不能溶解Eudragit S100粉末。Z(A)、Z(B)和Z(C)中CAB - 551 - 0.01的浓度分别等于X(A)、X(B)和X(C)中的总聚合物浓度（CAB - 551 - 0.01和Eudragit S100粉末）。使用扫描电子显微镜（SEM）来识别微球的形状和形态。在37℃（±0.5℃）下，在两种连续的不同pH介质（1.2±0.2，2小时；6.5±0.2，10小时）中对微球进行体外溶出研究。Z制剂在酸性和微中性介质中表现出较低的药物释放速率。另一方面，X制剂在酸性介质中显示出初始快速释放，随后在微中性pH溶出的早期阶段释放速率降低，这可能是由于Eudragit S100粉末在完全溶解之前发生了一些松弛和凝胶化，形成了凝胶网络，从而使剩余的药物得以释放。
