Biodegradable Microsphere-Hydrogel Ocular Drug Delivery System for Controlled and Extended Release of Bioactive Aflibercept In Vitro.
Biodegradable Microsphere-Hydrogel Ocular Drug Delivery System for Controlled and Extended Release of Bioactive Aflibercept In Vitro.
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DOI：
10.1080/02713683.2018.1533983
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发表时间：
2019-03
影响因子：
2
通讯作者：
Kang-Mieler JJ
中科院分区：
文献类型：
--
作者：
Liu W;Lee BS;Mieler WF;Kang-Mieler JJ
目前治疗新血管性眼病的标准需要反复玻璃体内注射抗血管内皮生长因子（anti- vegf）。本研究的目的是验证一种可降解的微球-热响应水凝胶给药系统（DDS），该系统能够以可控和延长的方式释放生物活性阿布西普6个月。DDS是用可降解的聚乙二醇-co-（l -乳酸）二丙烯酸酯/ n -异丙基丙烯酰胺（peg - pla - da /NIPAAm）热响应水凝胶悬浮负载afliberept的聚（乳酸-乙醇酸）微球制备的。采用碘-125放射性标记法对dds的包封效率和体外释放谱进行了表征。水凝胶的降解是通过干重的变化来确定的。通过使用LIVE/DEAD®法定量细胞活力来研究降解DDS副产物的细胞毒性。此外，采用斑点免疫印迹法和酶联免疫吸附法测定释放药物的生物活性。最后，用低温扫描电镜观察了热转化前后微球和水凝胶的形貌。微球-水凝胶DDS能够在6个月的控制和延长时间内释放具有生物活性的阿布西普。交联剂浓度和微球负荷量可控制阿布西普的释放量和释放速率。初始释放量（24 h内释放量）为37.35±4.92 ~ 74.56±6.16 μg（2、3 mM水凝胶，各载10、20 mg/ml微球），控制释放量为0.07 ~ 0.15 μg/d。较高peg - pla - da浓度（3mm）比较低浓度（2mm）降解更快。降解的DDS副产物在所有研究时间点均未发现明显的细胞毒性。释放药物的生物活性在整个释放期内保持在治疗水平。微球-水凝胶DDS是一种安全、可控的生物活性药物。这可能在治疗眼部新生血管方面比目前的大剂量注射疗法有显著的优势。
Current standard of care for neovascular eye diseases require repeated intravitreal bolus injections of anti-vascular endothelial growth factors (anti-VEGFs). The purpose of this study was to validate a degradable microsphere-thermoresponsive hydrogel drug delivery system (DDS) capable of releasing bioactive aflibercept in a controlled and extended manner for 6 months. The DDS was fabricated by suspending aflibercept-loaded poly(lactic-coglycolic acid) microspheres within a biodegradable poly(ethylene glycol)-co-(L-lactic acid) diacrylate/N-isopropylacrylamide (PEG-PLLA-DA/NIPAAm) thermoresponsive hydrogel. Encapsulation efficiency of DDSs and in vitro release profiles were characterized by iodine-125 radiolabeled aflibercept. The degradation of hydrogel was determined by dry weight changes. The cytotoxicity from degraded DDS byproducts was investigated by quantifying cell viability using LIVE/DEAD® assay. In addition, dot blot and enzyme-linked immunosorbent assay were used to determine the bioactivity of released drug. Finally, morphology of microspheres and hydrogel were investigated by cryo-scanning electron microscopy before and after thermal transformation. The microsphere-hydrogel DDS was capable of releasing bioactive aflibercept in a controlled and extended manner for 6 months. The amount and rate of aflibercept release can be controlled by both the cross-linker concentration and microspheres load amount. The initial burst (release within 24 h) was from 37.35 ± 4.92 to 74.56 ± 6.16 μg (2 and 3 mM hydrogel, each loaded with 10 and 20 mg/ml of microspheres, respectively), followed by controlled drug release of 0.07–0.15 μg/day. Higher PEG-PLLA-DA concentration (3 mM) degraded faster than the lower concentration (2 mM). No significant cytotoxicity from degraded DDS byproducts was found for all investigated time points. Bioactivity of released drug was maintained at therapeutic level over entire release period. The microsphere-hydrogel DDS is safe and can deliver bioactive aflibercept in a controlled manner. This may provide a significant advantage over current bolus injection therapies in the treatment of ocular neovascularization.