Lacasse F X, Filion M C, Phillips N C, Escher E, McMullen J N, Hildgen P
Faculty of Pharmacy, University of Montreal, Quebec, Canada.
Pharm Res. 1998 Feb;15(2):312-7. doi: 10.1023/a:1011935222652.
The objective of this work was to determine plasma protein adsorption and macrophage phagocytosis of biodegradable polyanhydride, polylactic acid and polylactic-co-glycolic acid microspheres prepared by both spray-drying and solvent evaporation techniques.
Microspheres were characterized by scanning electron microscopy (SEM), confocal laser microscopy, particle size distribution and zeta (zeta) potential determination. Plasma protein adsorption onto the microspheres was determined using a fluoroaldehyde reagent. Phagocytosis was evaluated by incubating microspheres containing the angiotensin II antagonist, L-158,809, with the macrophages in the presence or absence of the phagocytosis inhibitor cythochalasin D. The extent of phagocytosis was established by fluorescence determination of L-158,809 and by optical microscopy. The effect of amphiphilic poly(ethylene glycol) (PEG) derivatives on phagocytosis was determined using PEG-distearate incorporated into the microspheres.
The average diameter of the microspheres, which depended on the polymer and the initial formulation, ranged from 0.9 to 3.2 micrometers. Zeta potential studies showed strong negative values irrespective of the polymer used for the spray-dried formulations. The zeta potential was masked by the incorporation of PEG 400- or PEG 1,400-distearate in the formulation. Confocal laser microscopy showed a homogenous dispersion of PEG (measured as PEG-fluorescein) in the microspheres. Protein adsorption was not observed for any of the microsphere formulations following incubation with bovine serum. Incubation of microspheres with murine macrophages showed that PEG-distearate inhibited phagocytosis at appropriate levels (0.1% w/w). Higher levels > 1% w/w of PEG-distearate) resulted in enhanced association with macrophages, despite the presence of the phagocytosis inhibitor cytochalasin D, indicating fusion between the microspheres and the plasma membrane.
These results demonstrate that spray-dried PEG-containing microspheres can be manufactured and that an appropriate concentration of this excipient in microspheres results in decreased phagocytosis.
本研究旨在测定通过喷雾干燥和溶剂蒸发技术制备的可生物降解聚酸酐、聚乳酸和聚乳酸-乙醇酸共聚物微球的血浆蛋白吸附及巨噬细胞吞噬作用。
通过扫描电子显微镜（SEM）、共聚焦激光显微镜、粒度分布和zeta电位测定对微球进行表征。使用氟醛试剂测定微球上的血浆蛋白吸附。通过在有或无吞噬抑制剂细胞松弛素D存在的情况下，将含有血管紧张素II拮抗剂L-158,809的微球与巨噬细胞孵育来评估吞噬作用。通过对L-158,809进行荧光测定和光学显微镜观察来确定吞噬程度。使用掺入微球中的聚乙二醇二硬脂酸酯（PEG-distearate）来测定两亲性聚乙二醇（PEG）衍生物对吞噬作用的影响。
微球的平均直径取决于聚合物和初始配方，范围为0.9至3.2微米。zeta电位研究表明，无论用于喷雾干燥配方的聚合物如何，均呈现强负值。在配方中加入PEG 400-或PEG 1,400-二硬脂酸酯会掩盖zeta电位。共聚焦激光显微镜显示PEG（以PEG-荧光素测量）在微球中均匀分散。与牛血清孵育后，未观察到任何微球配方有蛋白吸附。将微球与小鼠巨噬细胞孵育表明，PEG-二硬脂酸酯在适当水平（0.1% w/w）时可抑制吞噬作用。更高水平（>1% w/w的PEG-二硬脂酸酯）导致与巨噬细胞的结合增强，尽管存在吞噬抑制剂细胞松弛素D，这表明微球与质膜之间发生了融合。
这些结果表明，可以制备含喷雾干燥PEG的微球，并且微球中该辅料的适当浓度会导致吞噬作用降低。
