Coatings from blends of Eudragit® RL and L55: a novel approach in pH-controlled drug release.
Coatings from blends of Eudragit® RL and L55: a novel approach in pH-controlled drug release.
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DOI：
10.1016/j.ijpharm.2014.09.023
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发表时间：
2014-12
影响因子：
5.8
通讯作者：
R. Wulff;Claudia S. Leopold
中科院分区：
文献类型：
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作者：
R. Wulff;Claudia S. Leopold
本研究的目的是考察以聚甲基丙烯酸季铵盐和甲基丙烯酸乙酯共聚物为包衣材料的茶碱微丸的释药行为。在有机溶液或水分散体中，以不同的共聚比例将Eudradit®RL PO(RL)和Eudradit®L 100-55(L55)的混合物包覆在微球上。一般来说，茶碱在pH为6.8的磷酸盐缓冲液中的渗透性低于在pH为1.2的盐酸中的渗透性。进一步的溶出实验表明，pH值的不同导致了药物释放的差异。对不同包衣水平和RL和L55混合比例的微丸的释药数据进行了历史数据的实验设计。药物在盐酸中的释放主要受包衣程度的影响，而在pH为6.8的磷酸盐缓冲液中药物释放的决定因素是共混比例。正如预期的那样，不同pH值下的溶出实验表明，药物的释放取决于解离的L55与RL的比例，因为电离是官能团相互作用的必要条件。与延迟释放固体制剂的溶出度试验(Ph.EUR.)结果表明，盐酸暴露后，在中性介质中保持了其独特的释药行为。这些发现表明，RL和L55在溶液包衣中的结合是一种很有前途的药物控制释放方法。
The aim of the present study was to investigate the drug release from theophylline pellets coated with blends of quaternary polymethacrylate and methacrylic acid–ethyl acrylate copolymers. Pellets were coated with blends of Eudragit®RL PO (RL) and Eudragit®L 100-55 (L55) in either organic solution or aqueous dispersion at various copolymer ratios. Generally, the coatings were less permeable for theophylline in phosphate buffer pH 6.8 than they were in hydrochloric acid pH 1.2. Further dissolution experiments revealed that the differences in drug release are caused by the different pH values. A design of experiments for historical data was performed on drug release data of pellets with different coating levels and blend ratios of RL and L55. Drug release in hydrochloric acid was predominantly affected by the coating level, whereas for drug release in phosphate buffer pH 6.8 the blend ratio was the determining factor. As expected, dissolution experiments at different pH values showed that drug release depends on the ratio of dissociated L55 to RL because ionization is a requirement for the functional groups to interact. With the dissolution test for delayed-release solid dosage forms (Ph. Eur.) it was demonstrated that the unique release behavior in neutral media is preserved after the exposition to hydrochloric acid. These findings indicate that the combination of RL and L55 in coatings prepared from solutions is a promising approach for controlled drug release.