胃溶型丙烯酸树脂乳液的制备

Preparation of stomachic acrylic resin emulsion

采用乳液聚合法,以甲基丙烯酸甲酯(MMA)和甲基丙烯酸二甲氨基乙酯(DM)为单体,制备了可直接用于药物包衣的胃溶型丙烯酸树脂乳液。结果表明,当温度为65℃,单体摩尔比为1∶1,引发剂和乳化剂用量分别为0.6%和0.3%,采用单体连续滴加法时,可制得稳定的乳液,聚合物分子量为14.9万。在180℃以下,产品的失重率基本不随温度而变,而在180℃以上,失重率随温度升高而增加。聚合物膜在缓冲溶液中的失重率随pH的增加而减小,当pH为1.0和2.0时,膜几乎全部溶解,pH为3.0时,膜的失重率为65.0%,在pH为4.0时,失重率迅速降低到32.8%,到pH为7.0时,膜已基本不溶。

Acrylic resin emulsion which can be used for drug coating directly was prepared by emulsion polymerization with methyl methacrylate（MMA） and 2-（di-mthylamino）ethyl methacrylate（DM） as monomers.The results showed that the stable emulsion can be successfully prepared when the temperature was 65 ℃,molar ratio of monomers was 1∶1,dosage of initiator and emulsifier was 0.6% and 0.3%,respectively,and the monomer was added continuously.Molecular weight of polymer was 1.49×105.Weightlessness rate of the product almost had no change with temperature change when the temperature was below 180 ℃,but increased with increasing temperature when the temperature was above 180 ℃.Weightlessness rate of the film in the buffer solution decreased with increasing pH,the film almost dissolved completely when the pH was 1.0 and 2.0,and weightlessness rate was 65.0% when pH was 3.0,then reduced to 32.8% rapidly when pH was 4.0,and the film was almost insoluble when pH increased to 7.0.