基于苯基乙烯基酮双亲性嵌段物的光敏延时释药乳剂

Photosensitive drug delivery emulsion based on amphiphilic block copolymer of phenyl vinyl ketone

聚苯基乙烯基酮(PPVK)在光照下能够发生主链断裂,基于这一特性,本文利用可逆加成-断裂链转移聚合(RAFT)以丙烯酸二甲氨基乙酯(DMAEA)和丙烯酸异辛酯(2-EHA)分别作为亲水性单体和疏水性单体,制备了双亲性三嵌段共聚物PDMAEA-b-PPVK-b-P(2-EHA),并利用该双亲性嵌段物作为乳化剂制备了油酸乙酯为环保油相的可光控延时释放的油包水(W/O)型农药乳剂。对乳液的制备稳定性、光敏感特性以及光控药物释放特性进行了研究。结果表明,在油相与水相体积比为2∶1、嵌段物亲水段与亲油段聚合度之比为1∶5、嵌段物添加量为0.03g/mL且内水相pH=5时,制得的乳液具有良好的稳定性;在紫外光照下,乳液能够很快发生破乳;草甘膦药物释放实验表明,乳液的药物释放表现出光控特性,紫外光照25min后,水相药物草甘膦释放率达90%左右。

Poly（phenyl vinyl ketone）（PPVK）can undergo main chain degradation under light irradiation.Basing on this characterization of the PPVK,N,N-dimethylaminoethyl acrylate（DMAEA）and 2-ethylhexyl acrylate（2-EHA）were chosen as the hydrophilic and hydrophobic monomer,respectively,to prepare an amphiphilic triblock copolymer PDMAEA-PPVK-P（2-EHA） by RAFT polymerization.This amphiphilic block copolymer was used as the polymeric emulsifier and ethyl oleate was used as oil phase to prepare environmental-friendly photosensitive W/O emulsion,which can undergo light-triggered drug release.The stability,photosensitivity,and light-triggered release behaviors of the emulsion were investigated.The results showed that the emulsion could achieve good stability under the condition that the volume ratio of O/W was 2∶1,the polymerization degree ratio of hydrophilic/hydrophobic segments of the block copolymer was 1∶5,the dosage of block copolymer is 0.03 g/mL and the pH of water phase was 5;the emulsion could undergo quick demulsification under UV light irradiation;the drug release experiment showed that the release behavior of glyphosate could be controlled by light,and the total release rate of glyphosate is about 90% after 25 min UV irradiation.