Faculty of Pharmacy, Department of Pharmaceutical Technology, University of Athens, Athens, Greece.
Drug Dev Ind Pharm. 2010 Aug;36(8):903-16. doi: 10.3109/03639040903585119.
Multilayer tablets are gaining importance in oral sustained drug delivery. They consist of an active matrix core and one or more layers applied during tableting which may act as barriers and regulate drug release.
To examine the release performance of two model drugs, diclofenac sodium and furosemide, from two- and three-layer drug delivery systems using as carriers hydrophilic swellable polymers, namely, Metolose, Polyox, Xantham gum, and an erodible material Gantrez.
All prepared formulations demonstrated sustained release profiles. They also indicated that the carrier characteristics (particularly swelling-expansion, erosion-dissolution) and drug solubility in combination with tablet structure considerably influenced the performance of examined formulations as well as their mode and mechanisms of release. In general our findings show that the differences in drug release between the two- and three-layer tablets are small as it appears that two-layer tablets exhibit a slightly higher release. Because of its greater erosion Gantrez formulations displayed faster release relative to Xantham gum, as did Metolose formulations compared to Polyox formulations. A faster release rate was also noted with diclofenac formulations compared to those of furosemide because of diclofenac's higher solubility mainly seen at early time period.
All three-layer Gantrez tablets containing either diclofenac or furosemide and the two-layer furosemide formulation demonstrated a biphasic release. The above indicate that both structures may be used successfully for sustained release drug delivery. In addition the use of multilayer tablets, consisting of materials with suitable properties, may result in modulation of drug release.
多层片剂在口服缓控释给药中越来越重要。它们由活性基质核心和一个或多个在压片过程中施加的层组成，这些层可以作为屏障并调节药物释放。
使用亲水溶胀聚合物（即 Metolose、Polyox、黄原胶和可蚀性材料 Gantrez）作为载体，考察两种模型药物双氯芬酸钠和呋塞米的双层和三层药物传递系统的释放性能。
所有制备的制剂均表现出持续释放的特征。它们还表明，载体特性（特别是溶胀-膨胀、侵蚀-溶解）以及药物在水中的溶解度与片剂结构相结合，极大地影响了所考察制剂的性能及其释放方式和机制。一般来说，我们的发现表明，双层和三层片剂之间的药物释放差异较小，因为双层片剂显示出稍微更高的释放。由于 Gantrez 制剂的侵蚀性更大，与黄原胶相比，Xantham 胶制剂显示出更快的释放，与 Polyox 制剂相比，Metolose 制剂也是如此。与呋塞米制剂相比，双氯芬酸钠制剂的释放速度也更快，这是因为双氯芬酸钠的溶解度更高，主要在早期观察到。
所有包含双氯芬酸钠或呋塞米的三层 Gantrez 片剂和含有呋塞米的双层片剂均表现出两相释放。上述结果表明，这两种结构都可以成功地用于缓控释给药。此外，使用具有适当性质的多层片剂可能会导致药物释放的调节。
