Effect of lecithin and MgCO3 as additives on the enzymatic activity of carbonic anhydrase encapsulated in poly(lactide-co-glycolide) (PLGA) microspheres.
Effect of lecithin and MgCO3 as additives on the enzymatic activity of carbonic anhydrase encapsulated in poly(lactide-co-glycolide) (PLGA) microspheres.
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DOI：
10.1016/s0304-4165(02)00153-8
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发表时间：
2002-02
期刊：
影响因子：
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通讯作者：
M. Sandor;Alex Riechel;I. Kaplan;E. Mathiowitz
中科院分区：
文献类型：
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作者：
M. Sandor;Alex Riechel;I. Kaplan;E. Mathiowitz
模型酶碳酸酐酶被封装并从通过新型相转化技术制成的聚丙交酯乙交酯 (PLGA) 微球 (1-3 μm) 中释放。卵磷脂在封装过程中用作表面活性剂，并掺入有机相、水相、两相中，或根本不掺入。还用水相中掺入的卵磷脂和聚合物相中掺入的碱性盐 MgCO3 制备了其他微球。通过 HPLC 和活性测定分析释放的碳酸酐酶、从微球中提取的蛋白质或与卵磷脂和 PLGA 一起孵育的酶，以确定这些添加剂对蛋白质完整性和活性的影响。与不含 MgCO3 的其他制剂相比，水相中的卵磷脂似乎增加了单体形式的酶的比例及其对提取蛋白质和释放蛋白质的活性。酶与 PLGA 降解产物的孵育表明微球内的酸性环境有助于封装蛋白质的不可逆失活。添加 MgCO3 通过减少酸诱导的裂解和非共价聚集的量，进一步增加了提取和释放的蛋白质中单体的量，但仍然大大降低了酶的活性。
A model enzyme, carbonic anhydrase, was encapsulated and released from poly(lactide-co-glycolide) (PLGA) microspheres (1–3 μm) made by a novel phase inversion technique. Lecithin was used as a surfactant in the encapsulation process and was incorporated in either the organic phase, aqueous phase, both phases, or not at all. Additional microspheres were also made with lecithin incorporated in the aqueous phase and a basic salt, MgCO3, in the polymeric phase. Released carbonic anhydrase, protein extracted from microspheres, or enzyme incubated with lecithin and PLGA were analyzed via HPLC and activity assay to determine the effect of these additives on protein integrity and activity. Lecithin in the aqueous phase appeared to increase the fraction of enzyme in monomeric form as well as its activity for both extracted protein and released protein as compared to the other formulations without MgCO3. Incubation of enzyme with PLGA degradation products indicated that the acidic environment within the microspheres aids in the irreversible inactivation of the encapsulated protein. Addition of MgCO3further increased the amount of monomer in both the extracted and released protein by decreasing the amount of acid-induced cleavage and noncovalent aggregation, but still greatly decreased the activity of the enzyme.