University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia.
Eur J Pharm Sci. 2013 Sep 27;50(1):114-22. doi: 10.1016/j.ejps.2013.04.029. Epub 2013 May 3.
Liquid crystalline systems with a lamellar structure have been extensively studied as dermal delivery systems. Ascorbyl palmitate (AP) is one of the most studied and used ascorbic acid derivatives and is employed as an antioxidant to prevent skin aging. The aim of this study was to develop and characterize skin-compliant dermal delivery systems with a liquid crystalline structure for AP. First, a pseudoternary phase diagram was constructed using Tween 80/lecithin/isopropyl myristate/water at a Tween 80/lecithin mass ratio of 1/1, and the region of lamellar liquid crystals was identified. Second, selected unloaded and AP-loaded lamellar liquid crystal systems were physicochemically characterized with polarizing optical microscopy, small-angle X-ray scattering, differential scanning calorimetry, and rheology techniques. The interlayer spacing and rheological parameters differ regarding quantitative composition, whereas the microstructure of the lamellar phase was affected by the AP incorporation, resulting either in additional micellar structures (at 25 and 32 °C) or being completely destroyed at higher temperature (37°C). After this, the study was oriented towards in vitro cytotoxicity evaluation of lamellar liquid crystal systems on a keratinocyte cell line. The results suggest that the lamellar liquid crystals that were developed could be used as a physiologically acceptable dermal delivery system.
具有层状结构的液晶体系已被广泛研究作为经皮给药系统。抗坏血酸棕榈酸酯（AP）是研究和使用最多的抗坏血酸衍生物之一，用作抗氧化剂来预防皮肤衰老。本研究旨在开发和表征具有层状液晶结构的符合皮肤的 AP 经皮给药系统。首先，使用 Tween 80/卵磷脂/肉豆蔻异丙酯/水在 Tween 80/卵磷脂质量比为 1/1 的条件下构建伪三元相图，并确定层状液晶区域。其次，用偏光显微镜、小角 X 射线散射、差示扫描量热法和流变学技术对未负载和负载 AP 的层状液晶体系进行物理化学表征。层间间距和流变学参数因定量组成而异，而层相的微观结构受到 AP 掺入的影响，导致形成额外的胶束结构（在 25 和 32°C）或在较高温度（37°C）下完全破坏。在此之后，研究方向转向角质形成细胞系上的层状液晶系统的体外细胞毒性评估。结果表明，所开发的层状液晶可以用作生理上可接受的经皮给药系统。
