Lewis Andrew, Tang Yiqing, Brocchini Steve, Choi Ji-Won, Godwin Antony
Biocompatibles UK Ltd, Weydon Lane, Farnham, Surrey, United Kingdom.
Bioconjug Chem. 2008 Nov 19;19(11):2144-55. doi: 10.1021/bc800242t.
The water-soluble, biocompatible polymer poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was evaluated for protein conjugation. PMPC is a zwitterionic polymer that is able to form a more compact conformation in aqueous solution than poly(ethylene glycol) (PEG). While a terminally functionalized N-hydroxysuccinimide derivative of PMPC was not efficient for conjugation to an amine moiety on interferon-alpha2a (IFN), we found that a bis-thiol specific derivative of PMPC could be conjugated after reduction of the disulfide bonds in IFN. Utilizing PMPC that displayed a similar hydrodynamic volume to 20 kDa PEG, we evaluated the in vitro antiviral and antiproliferative activity and pharmacokinetics of a PMPC-IFN conjugate. As a hygroscopic zwitterionic polymer, PMPC is able to form a compact conformation in aqueous solution, which was found to be more compact than PEG. This suggests that PMPC protein conjugates may display different plasma elimination characteristics than PEG protein conjugates. PMPC-IFN displayed marked resistance to antibody binding in Western blot analysis with a polyclonal anti-IFN antibody while displaying comparable in vitro antiviral and antiproliferative activity to PEG-IFN. During an in vivo pharmacokinetic study, the absorption t(1/2) for PMPC-IFN was considerably extended compared to the native IFN and 20 kDa PEG analogue. This is also consistent with the SDS-PAGE result where an apparent reduction in mobility through a hydrated medium was observed. The elimination t(1/2) was also vastly extended over the native IFN and twice the value of 20 kDa PEG-IFN. This suggests that tissue migration of PMPC-IFN occurs more slowly than the 20 kDa PEG-IFN despite their similarity in hydrodynamic volume, leading to an an improved depot effect, which could explain the longer elimination t(1/2). In this study, we demonstrate a potential use of PMPCylation as a novel tool for enhancing the pharmacokinetic profile of therapeutic proteins in ways that complement PEGylation.
对水溶性生物相容性聚合物聚（2-甲基丙烯酰氧基乙基磷酰胆碱）（PMPC）进行了蛋白质缀合评估。PMPC是一种两性离子聚合物，在水溶液中能够形成比聚乙二醇（PEG）更紧密的构象。虽然PMPC的末端功能化N-羟基琥珀酰亚胺衍生物与α2a干扰素（IFN）上的胺部分缀合效率不高，但我们发现PMPC的双硫醇特异性衍生物在IFN中的二硫键还原后可以缀合。利用与20 kDa PEG具有相似流体力学体积的PMPC，我们评估了PMPC-IFN缀合物的体外抗病毒和抗增殖活性以及药代动力学。作为一种吸湿性两性离子聚合物，PMPC能够在水溶液中形成紧密的构象，并发现其比PEG更紧密。这表明PMPC蛋白质缀合物可能表现出与PEG蛋白质缀合物不同的血浆消除特征。在使用多克隆抗IFN抗体的蛋白质印迹分析中，PMPC-IFN对抗体结合表现出显著抗性，同时其体外抗病毒和抗增殖活性与PEG-IFN相当。在体内药代动力学研究中，与天然IFN和20 kDa PEG类似物相比，PMPC-IFN的吸收半衰期（t(1/2)）显著延长。这也与SDS-PAGE结果一致，在该结果中观察到通过水合介质的迁移率明显降低。消除半衰期也比天然IFN大大延长，是20 kDa PEG-IFN值的两倍。这表明尽管PMPC-IFN与20 kDa PEG-IFN的流体力学体积相似，但其在组织中的迁移比20 kDa PEG-IFN更慢，从而导致改善的储库效应，这可以解释更长的消除半衰期（t(½)）。在本研究中，我们证明了PMPC化作为一种新型工具的潜在用途，可通过补充聚乙二醇化的方式来增强治疗性蛋白质的药代动力学特征。
