低临界胶束浓度PEGMA-b-PCL的制备及其 药物缓释性能

Preparation of the lower CMC nanocarrier PEGMA-b-PCL and its drug sustained-release properties

摘要:

以ε-己内酯（ε-CL）为疏水链段，聚乙二醇甲醚甲基丙烯酸酯（PEGMA）为亲水链段，4-氰基-4-[(十二烷基硫基硫羰基)硫基]戊酸（CDPA）为可逆加成-断裂链转移（RAFT）试剂，在以甲苯为溶剂、N2氛围、80 ℃、反应24 h的条件下，通过RAFT聚合法制备了两嵌段聚合物PEGMA-b-PCL。将其自组装为胶束用作纳米药物载体，并以姜黄素（Cur）为胶束负载药物。考察了两嵌段聚合物结构、分子量及分布，表征了胶束载体粒径、形貌，测试了胶束载体的载药和释药性能。结果表明，不同嵌段聚合物相对分子质量范围为478~7318，此类聚合物具有较低的临界胶束浓度（CMC），在常规条件下（pH=7.4）其范围为0.920~1.600 μg/mL。胶束载体粒径范围为:68.34~186.30 nm。当n(CDPA)∶n(ε-CL)=1∶200时，胶束载药量和包封率最高，可达12.05%和75.26%。在不同pH值环境下，药物缓释性能可达15 d，其中pH=5.0时释药量可达35.38%。

Abstract:

ε-caprolactone(ε-CL), polyethylene glycol methyl ether methacrylate (PEGMA), and 4-cyano-4-(dodecylsulfanylthiocarbonyl)sulfanylpentanoic acid (CDPA) were respectively considered to be hydrophobic chain segment, hydrophilic chain segment, and initiator in the polymerization reaction. A bi-block polymer PEGMA-b-PCL was prepared by reversible addition-fragmentation chain transfer(RAFT)polymerization and the polymer were self-assembled into polymeric micelle as nanocarriers. The results showed that the relative molecular weight of the polymer was in the range of 478-7318, and the size distribution of the micelles was 68.34-186.30 nm. The polymeric micelle critical micelle concentration (CMC) (pH=7.4, 0.920 μg/mL~1.600 μg/m L) is lower. When n (CDPA): n(ε-CL) = 1: 200, the drug loading capacity and encapsulation efficiency of drug curcumin(Cur)loaded micelles are the as high as 12.05% and 75.26%, respectively. Under different conditions, the drug sustained release behaviour can be carried?out within 15 days, and the cumulative release amount of the drug can reach as high as 35.38% in the aqueous solution (pH=5.0).