Subhaga C S, Ravi K G, Sunny M C, Jayakrishnan A
College of Pharmaceutical Sciences, Medical College, Trivandrum, India.
J Microencapsul. 1995 Nov-Dec;12(6):617-25. doi: 10.3109/02652049509006792.
In spite of several biomedical applications of polyurethanes, very little attention has been focused on these polymers for controlled drug delivery. In this study, an aliphatic polyurethane, Tecoflex, was evaluated as a microsphere matrix for the controlled release of theophylline. Polyurethane microspheres containing theophylline were prepared using a solvent evaporation technique from a dichloromethane solution of the polymer containing the drug. A dilute solution of poly(vinyl alcohol) served as the dispersion medium. Microspheres of good spherical geometry having theophylline content of 35% could be prepared by the technique. The release of the drug from the microspheres was examined in simulated gastric and intestinal fluids at 37 degrees C. While a large burst effect was observed in gastric fluid, in the intestinal fluid a close to zero-order release was seen. Attempts were made to modulate the release by incorporating poly(ethylene glycol) in the matrix and also coating the spheres with paraffin wax. Preliminary data indicate that polyurethanes could be interesting matrices for controlled drug delivery.
尽管聚氨酯有多种生物医学应用，但在用于控释给药方面，人们对这些聚合物的关注却很少。在本研究中，对一种脂肪族聚氨酯Tecoflex作为茶碱控释的微球基质进行了评估。含茶碱的聚氨酯微球是采用溶剂蒸发技术，从含有药物的聚合物二氯甲烷溶液中制备的。聚乙烯醇稀溶液用作分散介质。通过该技术可以制备出具有良好球形几何形状、茶碱含量为35%的微球。在37℃的模拟胃液和肠液中考察了药物从微球中的释放情况。虽然在胃液中观察到较大的突释效应，但在肠液中则呈现接近零级的释放。尝试通过在基质中加入聚乙二醇以及用石蜡对微球进行包衣来调节释放。初步数据表明，聚氨酯可能是用于控释给药的有趣基质。
