Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121 Ferrara, Italy.
Colloids Surf B Biointerfaces. 2013 Dec 1;112:322-9. doi: 10.1016/j.colsurfb.2013.07.067. Epub 2013 Aug 8.
The aim of the present study was to develop controlled release inhalable lipid microparticles (LMs) loaded with the antioxidant flavonoid, quercetin and to investigate the interaction of these microparticles with A549 pulmonary alveolar epithelial cells. The LMs were produced using different lipidic materials and surfactants, by melt emulsification followed by a sonication step. The most efficient modulation of the in vitro release of quercetin was achieved by the LMs prepared with tristearin and hydrogenated phosphatidylcholine, which were used for subsequent studies. These LMs exhibited a quercetin loading of 11.8±0.3%, and a volume median diameter, determined by laser diffraction, of 4.1±0.2μm. Moreover, their mass median aerodynamic diameter (4.82±0.15μm) and fine particle fraction (27.2±3.9%), as measured by multi-stage liquid impinger, were suitable for pulmonary delivery. Quercetin was found to be highly unstable (complete decomposition within 6-h incubation) in Ham's F-12 medium used for A549 cell culture. Degradation was markedly reduced (16.4% of the initial quercetin content still present after 24-h incubation) after encapsulation in the lipid particle system. Viability studies performed by lactate dehydrogenase assay, demonstrated that quercetin LMs showed no significant cytotoxicity on the A549 cells, over the concentration 0.1-5μM. The uptake of quercetin by the A549 lung alveolar cells was also investigated. After 4-h incubation, the accumulation of quercetin in the A549 cells was significantly higher (2.3-fold increase) for the microparticle entrapped flavonoid when compare to non-encapsulated quercetin. The enhanced intracellular delivery of quercetin achieved by the LMs is likely due to the flavonoid stabilization after encapsulation.
本研究旨在开发载有抗氧化剂类黄酮槲皮素的控释吸入性脂质微球（LMs），并研究这些微球与 A549 肺泡上皮细胞的相互作用。LMs 采用不同的脂质材料和表面活性剂，通过熔融乳化后进行超声处理制备而成。通过采用三硬脂酸甘油酯和氢化磷脂酰胆碱制备的 LMs，可实现体外释放槲皮素的最有效调控，因此在后续研究中使用了这些 LMs。这些 LMs 的槲皮素载药量为 11.8±0.3%，通过激光衍射测定的体积中值直径为 4.1±0.2μm。此外，通过多阶段液体撞击器测定的质量中值空气动力学直径（4.82±0.15μm）和细颗粒分数（27.2±3.9%）适合肺部给药。在用于 A549 细胞培养的 Ham's F-12 培养基中，槲皮素的稳定性很差（6 小时孵育后完全分解）。在脂质颗粒系统中进行包封后，降解明显减少（孵育 24 小时后仍存在初始槲皮素含量的 16.4%）。通过乳酸脱氢酶测定进行的活力研究表明，在 0.1-5μM 的浓度范围内，载有槲皮素的 LMs 对 A549 细胞没有明显的细胞毒性。还研究了 A549 肺肺泡细胞对槲皮素的摄取。孵育 4 小时后，与未包封的槲皮素相比，A549 细胞中包封的黄酮类化合物的槲皮素积累量显著增加（增加了 2.3 倍）。LMs 实现的载有槲皮素的细胞内递呈的增强可能是由于包封后黄酮类化合物的稳定化。
