Laboratory of Pharmaceutical Technology and Biopharmaceutics, University of Bonn, Bonn, Germany.
Int J Pharm. 2010 May 10;390(2):208-13. doi: 10.1016/j.ijpharm.2010.02.001. Epub 2010 Feb 10.
Lipid nanocapsules are recently developed lipid nanocarriers for delivery of lipophilic drugs. Due to their small size and biocompatible nature, lipid nanocapsules (LNC) may be promising carriers for drug delivery with different routes of administration. The aim of this work was to study the effect of formulation variables on the in vitro drug release from LNC. Ibuprofen as a model drug was entrapped in the oily core while Cremophor A25 and Cremophor A6 were used as hydrophilic surfactants in different ratios ranging from 1:1 to 1:0. All the prepared LNC were of comparable particle sizes around 50nm. Varying Cremophor compositions as well as the presence of lecithin, cetyl or stearyl alcohol had no significant effect on the in vitro drug release profiles. However, drug release rates increased significantly with increasing the temperature from 4 to 50 degrees C, i.e. the flux increased from 1.5 to 7microg/(cm(2)min). This was explained by the increased ibuprofen-lipid interactions at reduced temperature where the increased viscosity of the lipid significantly slows down the drug diffusion to the external aqueous phase. In summary, the physicochemical properties of the drug as well as the oil phase have a high impact on the drug release rate while the surfactant type, composition or density exerted only a minor effect.
脂质纳米胶囊是最近开发的用于递送脂溶性药物的脂质纳米载体。由于其粒径小且具有生物相容性，脂质纳米胶囊（LNC）可能是具有不同给药途径的药物传递有前途的载体。本工作旨在研究制剂变量对 LNC 体外药物释放的影响。布洛芬作为模型药物被包封在油核中，而 Cremophor A25 和 Cremophor A6 则以不同比例（1:1 至 1:0）用作亲水表面活性剂。所有制备的 LNC 的粒径均约为 50nm。改变 Cremophor 组成以及存在卵磷脂、鲸蜡醇或硬脂醇对体外药物释放曲线没有显著影响。然而，随着温度从 4°C 升高到 50°C，药物释放速率显著增加，即通量从 1.5μg/（cm2min）增加到 7μg/（cm2min）。这是由于在降低温度下布洛芬-脂质相互作用增加，脂质的增加粘度显著减缓药物扩散到外部水相。总之，药物的物理化学性质以及油相对药物释放速率有很大影响，而表面活性剂类型、组成或密度仅产生较小影响。
