PEGylation is the standard approach for prolonging the plasma exposure of protein therapeutics but has limitations. We explored whether polymers prepared by Reversible Addition-Fragmentation chain-Transfer (RAFT) may provide better alternatives to polyethylene glycol (PEG). Four RAFT polymers were synthesised with varying compositions, molar mass (M_n), and structures, including a homopolymer of N-(2-hydroxypropyl)methacrylamide, (pHPMA) and statistical copolymers of HPMA with poly(ethylene glycol methyl ether acrylate) p(HPMA-co-PEGA); HPMA and N-acryloylmorpholine, p(HPMA-co-NAM); and HPMA and N-isopropylacrylamide, p(HPMA-co-NIPAM). The intravenous pharmacokinetics of the polymers were then evaluated in rats. The in vitro activity and in vivo pharmacokinetics of p(HPMA-co-NIPAM)-conjugated trastuzumab Fab' and full length mAb were then evaluated. p(HPMA-co-NIPAM) prolonged plasma exposure more avidly compared to the other p(HPMA) polymers or PEG, irrespective of molecular weight. When conjugated to trastuzumab-Fab', p(HPMA-co-NIPAM) prolonged plasma exposure of the Fab' similar to PEG-Fab'. The generation of anti-PEG IgM in rats 7 days after intravenous and subcutaneous dosing of p(HPMA-co-NIPAM) conjugated trastuzumab mAb was also examined and was shown to exhibit lower immunogenicity than the PEGylated construct. These data suggest that p(HPMA-co-NIPAM) has potential as a promising copolymer for use as an alternative conjugation strategy to PEG, to prolong the plasma exposure of therapeutic proteins.

聚乙二醇化是延长蛋白质治疗药物血浆暴露的标准方法，但有局限性。我们探讨了通过可逆加成断裂链转移 (RAFT) 制备的聚合物是否可以提供更好的聚乙二醇 (PEG) 替代品。合成了四种具有不同组成、摩尔质量 ( M _n ) 和结构的RAFT 聚合物，包括N -(2-羟丙基) 甲基丙烯酰胺 (pHPMA)的均聚物和 HPMA 与聚（乙二醇甲基醚丙烯酸酯）p 的统计共聚物(HPMA- co- PEGA)；HPMA和N-丙烯酰吗啉，p(HPMA- co- NAM)；和 HPMA 和N-异丙基丙烯酰胺，p(HPMA- co-NIPAM）。然后在大鼠中评估聚合物的静脉内药代动力学。的体外活性和体内P（HPMA-的药代动力学共-NIPAM）缀合的曲妥珠单抗Fab”和全长单克隆抗体然后评价。与其他 p(HPMA) 聚合物或 PEG 相比，p(HPMA - co- NIPAM) 更热衷于延长血浆暴露时间，而与分子量无关。当与曲妥珠单抗-Fab'缀合时，p(HPMA- co- NIPAM)延长了Fab'的血浆暴露，类似于PEG-Fab'。静脉和皮下给药p(HPMA- co) 7天后大鼠抗PEG IgM的产生-NIPAM) 缀合的曲妥珠单抗 mAb 也进行了检查，并且显示出比聚乙二醇化构建体更低的免疫原性。这些数据表明 p(HPMA- co- NIPAM) 具有作为一种有前途的共聚物的潜力，可用作 PEG 的替代缀合策略，以延长治疗性蛋白质的血浆暴露。