CIEPQPF, Department of Chemical Engineering, University of Coimbra, Polo II, Pinhal de Marrocos, P-3030-790 Coimbra, Portugal.
Center for Research and Development in Food Cryotechnology (CCT-Conicet La Plata, UNLP), RA-1900, Argentina.
Colloids Surf B Biointerfaces. 2018 Apr 1;164:50-57. doi: 10.1016/j.colsurfb.2018.01.018. Epub 2018 Feb 3.
Liposomes are exceptional carriers for therapeutic drug delivery. However, they generally suffer from poor cell penetration, low half-life in bloodstream and loss of functionality during storage. To overcome these problems some strategies can be applied, such as functionalization with polymers and the use of protective molecules during dehydration processes. This work reports a complete study about the stability, including freeze-drying in the presence of trehalose, storage and internalization into HEp-2 cells, of stable formulations of pH sensitive polymer-liposome complexes (PLC) composed of soybean lecithin and crosslinked/non-crosslinked poly(acrylic acid) with a cholesterol end-group (CHO-PAA). The results showed that the average hydrodynamic particle size of the complexes persisted unaffected for approximately 75 days after freeze-drying in the presence of 10% w/v trehalose. The efficiency of calcein encapsulation and release profiles in physiologic conditions exhibited no significant alterations when stored for 0 and 1 month, and for 2 and 3 months of storage the calcein release increased with time. The stored complexes were efficiently uptaken into HEp-2-cells, as determined by confocal microscopy. In all cases, the percentage of viable cells was above 90%, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, indicating no potential toxicity. Finally, transepithelial transport assays demonstrated that both fresh and 2 months-stored complexes could transport their calcein content through HEp-2 monolayers over time.
脂质体是治疗药物传递的特殊载体。然而，它们通常存在细胞穿透性差、血液半衰期短以及在储存过程中失去功能等问题。为了克服这些问题，可以采用一些策略，如聚合物功能化和在脱水过程中使用保护分子。本工作全面研究了稳定的 pH 敏感聚合物-脂质体复合物（PLC）的稳定性，包括在海藻糖存在下的冻干、储存和内化进入 HEp-2 细胞，该复合物由大豆卵磷脂和带胆固醇末端基团的交联/非交联聚丙烯酸（CHO-PAA）组成。结果表明，在 10%w/v 海藻糖存在下冻干后，复合物的平均水动力粒径在大约 75 天内保持不变。在储存 0 和 1 个月以及 2 和 3 个月时，在生理条件下包封和释放的效率没有明显变化，而随着时间的推移，钙黄绿素的释放增加。通过共聚焦显微镜确定储存的复合物被有效地摄取到 HEp-2 细胞中。在所有情况下，通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐测定法，活细胞的百分比均高于 90%，表明没有潜在的毒性。最后，跨上皮转运实验表明，新鲜和储存 2 个月的复合物都可以随着时间的推移通过 HEp-2 单层转运其钙黄绿素含量。
