The use of asymmetrical flow field-flow fractionation with on-line detection in the study of drug retention within liposomal nanocarriers and drug transfer kinetics
The use of asymmetrical flow field-flow fractionation with on-line detection in the study of drug retention within liposomal nanocarriers and drug transfer kinetics
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DOI：
10.1016/j.jpba.2016.02.037
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发表时间：
2016-05-30
影响因子：
3.4
通讯作者：
Brandl, Martin
中科院分区：
文献类型：
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作者：
Hinna, Askell Hvid;Hupfeld, Stefan;Brandl, Martin
由于其增溶能力，脂质体（磷脂囊泡）适合于设计用于静脉内施用水溶性差的药物化合物的制剂。尽管这种制剂具有良好的体外稳定性，药物泄漏最小，但在静脉内注射时，由于药物转移至血浆蛋白和细胞膜，存在药物过早损失的风险。在这里，我们报告了Hinna及其同事在2014年对最近引入的简单体外预测工具的改进，该工具使小的载药（供体）脂质体与大的受体脂质体接触，后者作为模拟体内生物汇的模型。随后使用不对称流场流分级（AF 4）分离供体和受体脂质体，在此期间，将样品暴露于相当于约600稀释因子的大体积洗脱液中。供体和受体级分中的模型药物含量通过在线UV/维斯消光测量（校正浊度）和收集级分的离线HPLC测量进行定量。改进的方法允许供体和受体囊泡的（近）基线分离以及不仅供体的药物含量的可靠定量-而且现在还由于其改进的尺寸均匀性、胶体稳定性和降低的浊度而允许受体脂质体的药物含量的可靠定量。这种改进，在以前报道的方法允许同时定量的药物转移和药物释放到水相。通过在特定孵育时间取样，测定了模型化合物p-THPP（5，10，15，20-四（4-羟基苯基）-21H，23H-卟啉）的释放和转移动力学。p-THPP在结构上与光敏剂替莫泊芬密切相关，替莫泊芬在临床上使用并在脂质体制剂中进行评估。转移p-THPP受体囊泡遵循第一级动力学与半衰期约300分钟。正如预期的那样，供体和受体囊泡之间的平衡分布是成比例的脂质质量比。发现p-THPP的初始快速转移（类似于5%），并通过确定分离期间供体和受体之间的转移程度来进一步研究。发现供体相和受体相在几分钟内分离，并且只有少量（
Due to their solubilizing capabilities, lip osomes (phospholipid vesicles) are suited for designing formulations for intravenous administration of drug compounds which are poorly water-soluble. Despite the good in vitro stability of such formulations with minimal drug leakage, upon i.v. injection there is a risk of premature drug loss due to drug transfer to plasma proteins and cell membranes. Here we report on the refinement of a recently introduced simple in vitro predictive tool by Hinna and colleagues in 2014, which brings small drug loaded (donor) liposomes in contact with large acceptor liposomes, the latter serving as a model mimicking biological sinks in the body. The donor- and acceptor-liposomes were subsequently separated using asymmetrical flow field-flow fractionation (AF4), during which the sample is exposed to a large volume of eluent which corresponds to a dilution factor of approximately 600. The model drug content in the donor- and acceptor fraction was quantified by on-line UV/VIS extinction measurements with correction for turbidity and by off-line HPLC measurements of collected fractions. The refined method allowed for (near) baseline separation of donor and acceptor vesicles as well as reliable quantification of the drug content not only of the donor- but now also of the acceptor-liposomes due to their improved size-homogeneity, colloidal stability and reduced turbidity. This improvement over the previously reported approach allowed for simultaneous quantification of both drug transfer and drug release to the aqueous phase. By sampling at specific incubation times, the release and transfer kinetics of the model compound p-THPP (5,10,15,20-tetrakis(4-hydroxyphenyl)21H,23H-poiphine) was determined. p-THPP is structurally closely related to the photosensitizer temoporfin, which is in clinical use and under evaluation in liposomal formulations. The transfer of p-THPP to the acceptor vesicles followed 1st order kinetics with a half-life of approximately 300 min. As expected, equilibrium distribution between donor and acceptor vesicles was proportional to the lipid mass ratio. An initial rapid transfer of p-THPP was found (similar to 5%) and investigated further by determining the extent of transfer between donor and acceptor during separation. The donor- and acceptor phase were found to be separated within few minutes and only minor (