Cao Qing-Ri, Kim Tae-Wan, Lee Beom-Jin
National Research Laboratory for Bioavailability Control, College of Pharmacy, Kangwon National University, Chuncheon, Republic of Korea.
Int J Pharm. 2007 Jul 18;339(1-2):19-24. doi: 10.1016/j.ijpharm.2007.04.016. Epub 2007 Apr 24.
Two types of the carnauba wax-based lipophilic matrix tablet using spray-dried granules (SDT) or directly compressible powdered mixtures (DCT) were prepared for sustained release. The model drug was a highly water-soluble potassium citrate and loaded about 74% of the total tablet weight. The SDT slowly eroded and disintegrated during the release study without showing sustained release when the hydrophilic excipients were added. In contrast, the DCT was more efficient for sustained release. The release rate decreased with increasing carnauba wax concentration. In particular, the sustained release rate was markedly pronounced when the lipophilic stearyl alcohol and stearic acid were combined with the carnauba wax. The surface of the intact DCT appeared to be smooth and rusty. The DCT rose to the surface from the bottom of the vessel during the release test, and numerous pores and cracks with no signs of disintegration were also observed after the release test. The release profile was dependent on the formulation composition and preparation method of the matrix tablet. Diffusion-controlled leaching through the channels of the pores and cracks of the lipophilic matrix tablet (DCT) is a key to the sustained release.
制备了两种基于巴西棕榈蜡的亲脂性基质片剂，分别采用喷雾干燥颗粒（SDT）或直接压片的粉末混合物（DCT）来实现药物的缓释。模型药物为高水溶性的柠檬酸钾，其含量约占片剂总重量的74%。在释放研究过程中，当添加亲水性辅料时，SDT会缓慢侵蚀并崩解，未呈现出缓释效果。相比之下，DCT在缓释方面更有效。释放速率随巴西棕榈蜡浓度的增加而降低。特别是，当亲脂性的硬脂醇和硬脂酸与巴西棕榈蜡结合时，缓释速率显著提高。完整的DCT片剂表面看起来光滑且呈铁锈色。在释放试验中，DCT从容器底部升至表面，释放试验后还观察到许多孔隙和裂缝，且无崩解迹象。释放曲线取决于基质片剂的配方组成和制备方法。通过亲脂性基质片剂（DCT）的孔隙和裂缝通道进行扩散控制的溶出是实现缓释的关键。
