Department of Pharmaceutical Chemistry, Dolphin (PG) Institute of Biomedical and Natural Sciences, Manduwala, Dehradun, Uttarakhand, India.
J Mater Sci Mater Med. 2011 Jan;22(1):125-35. doi: 10.1007/s10856-010-4192-4. Epub 2010 Dec 5.
Enteric copolymers of acrylic acid and methyl methacrylate (2.5:7.5 and 2:8) were prepared using tetrahydrofuran as solvent and AIBN as free radical initiator for colon targeting. FTIR and (1)H NMR spectra of the copolymers showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. Flurbiprofen sodium microspheres (M1 and M2) made with the copolymers, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -57.8 and -53.7 mV) and contained 5.47 and 5.89% drug. FTIR spectrum of microspheres showed peaks for aromatic C = C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. PXRD revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26°C against broad endotherms of copolymers and microspheres. The microspheres released 43 and 36% drug at pH 6.8 in 2 h and 99 and 96% at pH 7.4 in next 3-4 h.The microspheres did not adhere on gastric-mucosa at pH 1.2 but showed mucoadhesion time of 18 min and 9 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in colon, suggesting the potential of the hemocompatible copolymers for pH dependent colon targeted drug delivery system.
丙烯酸和甲基丙烯酸甲酯的肠溶性共聚物（2.5:7.5 和 2:8）以四氢呋喃为溶剂，以 AIBN 为自由基引发剂，用于结肠靶向。共聚物的 FTIR 和 1H NMR 谱表明，单体中不存在乙烯基键/质子，表明聚合成功。用共聚物通过油/油溶剂蒸发法制备的氟比洛芬钠微球（M1 和 M2）为球形，带负电荷（zeta 电位-57.8 和-53.7 mV），载药量为 5.47%和 5.89%。微球的 FTIR 谱显示出芳族 C = C 伸缩和取代苯环的峰，表明氟比洛芬被包埋。PXRD 显示氟比洛芬的结晶结构，而共聚物和微球为无定形。DSC 热图谱显示氟比洛芬钠在 129.26°C 有尖锐的熔融吸热峰，而共聚物和微球则有宽的吸热峰。微球在 pH 6.8 下 2 小时内释放 43%和 36%的药物，在 pH 7.4 下接下来的 3-4 小时内释放 99%和 96%的药物。微球在 pH 1.2 时不粘附在胃黏膜上，但在 pH 6.8 时显示出 18 分钟和 9 分钟的黏膜黏附时间。因此，口服微球将在结肠中释放药物，这表明这些血液相容性共聚物具有用于 pH 依赖性结肠靶向药物传递系统的潜力。
