Department for the Postgraduate Programme in Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brasil.
J Pharm Pharmacol. 2010 Jan;62(1):35-45. doi: 10.1211/jpp.62.01.0003.
This study aimed to investigate the distribution and release profile in the skin of a lipophilic model molecule, octylmethoxycinnamate (OMC), loaded in poly(epsilon-caprolactone) nanocapsules (NC) by the Franz cell method.
Nanocapsules were formulated in a hydroxyethylcellulose gel and compared to the same gel containing 5% of free OMC as control. A new extraction method was used to discriminate the OMC still entrapped in the NC from free OMC released in the skin strata. The OMC extraction from the skin was performed using acetonitrile, which broke the NC, or isopropyl myristate, which kept the NC intact.
When isopropylmyristate was used to determine the OMC released from NC, the results showed that more than 80% of the OMC was released from the NC at the skin surface after 6 h, whereas only 30% was released in the stratum corneum and epidermis.
It is suggested that the mechanism of release is different at the surface and in viable skin, probably due to the different local environments surrounding the NC. The small amount of OMC that reached the dermis was no longer encapsulated, suggesting that the NC did not reach the dermis. The viable epidermis seemed to be the limiting barrier against NC diffusion into the skin.
本研究旨在通过 Franz 细胞法研究亲脂性模型分子辛甲氧肉桂酸（OMC）负载于聚己内酯纳米囊（NC）中的分布和释放情况。
将纳米囊配制在羟乙基纤维素凝胶中，并与含有 5%游离 OMC 的相同凝胶作为对照进行比较。采用一种新的提取方法来区分仍包封在 NC 中的 OMC 与释放到皮肤层中的游离 OMC。使用乙腈或肉豆蔻异丙酯从皮肤中提取 OMC，前者可以破坏 NC，后者则保持 NC 完整。
当使用肉豆蔻异丙酯来确定 NC 中释放的 OMC 时，结果表明，6 小时后，超过 80%的 OMC 从 NC 释放到皮肤表面，而只有 30%释放到角质层和表皮中。
这表明释放机制在皮肤表面和活皮之间是不同的，可能是由于 NC 周围的局部环境不同。到达真皮的少量 OMC 不再被包裹，这表明 NC 并未到达真皮。活表皮似乎是 NC 扩散进入皮肤的限制屏障。
