Serina Therapeutics, Inc., 601 Genome Way, Huntsville, AL 35806, United States.
Bioconjug Chem. 2011 May 18;22(5):976-86. doi: 10.1021/bc200049d. Epub 2011 Apr 20.
Polyoxazoline polymers with methyl (PMOZ), ethyl (PEOZ), and propyl (PPOZ) side chains were prepared by the living cationic polymerization method and purified by ion-exchange chromatography. The following properties of polyoxazoline (POZ) were measured: apparent hydrodynamic radius by aqueous size-exclusion chromatography, relative lipophilicity by reverse-phase chromatography, and viscosity by cone-plate viscometry. The PEOZ polymers of different molecular weights were first functionalized and then conjugated to model biomolecules such as bovine serum albumin, catalase, ribonuclease, uricase, and insulin. The conjugates of catalase, uricase, and ribonuclease were tested for in vitro activity using substrate-specific reaction methods. The conjugates of insulin were tested for glucose lowering activity by injection to naïve Sprague-Dawley rats. The conjugates of BSA were injected into New Zealand white rabbits and serum samples were collected periodically and tested for antibodies to BSA. The safety of POZ was also determined by acute and chronic dosing to rats. The results showed that linear polymers of POZ with molecular weights of 1 to 40 kDa can easily be made with polydispersity values below 1.10. Chromatography results showed that PMOZ and PEOZ have a hydrodynamic volume slightly lower than PEG; PEOZ is more lipophilic than PMOZ and PEG; and PEOZ is significantly less viscous than PEG especially at the higher molecular weights. When PEOZ was attached to the enzymes catalase, ribonuclease, and uricase, the in vitro activity of the resultant bioconjugates depended on the extent of protein modification. POZ conjugates of insulin lowered blood glucose levels for a period of 8 h when compared to 2 h for insulin alone. PEOZ, like PEG, was also able to successfully attenuate the immunogenic properties of BSA. The POZ polymers (10 and 20 kDa) are safe when administered intravenously to rats, and the maximum tolerated dose (MTD) was greater than 2 g/kg. Blood counts, serum chemistry, organ weights, and the histopathology of key organs were normal. These results conclude that POZ has the desired drug delivery properties for a new biopolymer.
聚恶唑啉聚合物具有甲基（PMOZ）、乙基（PEOZ）和丙基（PPOZ）侧链，通过阳离子活性聚合方法制备，并通过离子交换色谱法纯化。测量了聚恶唑啉（POZ）的以下性能：水相尺寸排阻色谱法测定的表观流体力学半径、反相色谱法测定的相对亲脂性和锥板粘度计测定的粘度。首先对不同分子量的 PEOZ 聚合物进行功能化，然后与牛血清白蛋白、过氧化氢酶、核糖核酸酶、尿酸酶和胰岛素等模型生物分子偶联。使用底物特异性反应方法测试过氧化氢酶、尿酸酶和核糖核酸酶的偶联物的体外活性。通过注射到新的斯普拉格-道利大鼠来测试胰岛素偶联物的降血糖活性。将 BSA 偶联物注射到新西兰白兔中，并定期收集血清样本，并用 BSA 抗体进行测试。还通过急性和慢性给大鼠给药来确定 POZ 的安全性。结果表明，分子量为 1 至 40 kDa 的 POZ 线性聚合物很容易制备，多分散性值低于 1.10。色谱结果表明，PMOZ 和 PEOZ 的流体力学体积略低于 PEG；PEOZ 比 PMOZ 和 PEG 更亲脂；PEOZ 的粘度明显低于 PEG，尤其是在较高的分子量下。当 PEOZ 连接到过氧化氢酶、核糖核酸酶和尿酸酶时，所得生物缀合物的体外活性取决于蛋白质修饰的程度。与单独胰岛素相比，胰岛素的 8 小时时，PEOZ 缀合物可降低血糖水平。POZ 与 PEG 一样，也能够成功减弱 BSA 的免疫原性。PEOZ 聚合物（10 和 20 kDa）静脉内给予大鼠是安全的，最大耐受剂量（MTD）大于 2 g/kg。血细胞计数、血清化学、器官重量和关键器官的组织病理学均正常。这些结果表明，POZ 具有作为新型生物聚合物的所需药物输送特性。
