Programa de Pós-Graduação em Nanotecnologia Farmacêutica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Eur J Pharm Biopharm. 2011 Sep;79(1):95-101. doi: 10.1016/j.ejpb.2011.03.008. Epub 2011 Mar 22.
The aims of this work were to increase the photostability and to reduce the skin permeation of tretinoin through nanoencapsulation. Tretinoin is widely used in the topical treatment of various dermatological diseases such as acne, psoriasis, skin cancer, and photoaging. Tretinoin-loaded lipid-core polymeric nanocapsules were prepared by interfacial deposition of a preformed polymer. Carbopol hydrogels containing nanoencapsulated tretinoin presented a pH value of 6.08±0.14, a drug content of 0.52±0.01 mg g(-1), pseudoplastic rheological behavior, and higher spreadability than a marketed formulation. Hydrogels containing nanoencapsulated tretinoin demonstrated a lower photodegradation (24.17±3.49%) than the formulation containing the non-encapsulated drug (68.64±2.92%) after 8h of ultraviolet A irradiation. The half-life of the former was seven times higher than the latter. There was a decrease in the skin permeability coefficient of the drug by nanoencapsulation, independently of the dosage form. The liquid suspension and the semisolid form provided K(p)=0.31±0.15 and K(p)=0.33±0.01 cm s(-1), respectively (p≤0.05), while the samples containing non-encapsulated tretinoin showed K(p)=1.80±0.27 and K(p)=0.73±0.12 cm s(-1) for tretinoin solution and hydrogel, respectively. Lag time was increased two times by nanoencapsulation, meaning that the drug is retained for a longer time on the skin surface.
本研究旨在提高维 A 酸的光稳定性并减少其经皮渗透。维 A 酸广泛用于治疗各种皮肤病，如痤疮、银屑病、皮肤癌和光老化等，常作为局部治疗药物。维 A 酸载药脂核聚合物纳米囊由预聚物界面沉积法制备。载纳米囊维 A 酸的卡波姆水凝胶的 pH 值为 6.08±0.14，药物含量为 0.52±0.01mg/g，具有假塑性流变学特性和比市售制剂更高的铺展性。经 8h 紫外线 A 照射后，载纳米囊维 A 酸的凝胶制剂光降解率（24.17±3.49%）明显低于非包封药物制剂（68.64±2.92%），前者的半衰期是后者的 7 倍。纳米包封降低了药物的经皮渗透系数，与制剂形式无关。液体混悬剂和半固体制剂的渗透系数分别为 K(p)=0.31±0.15 和 K(p)=0.33±0.01cm/s（p≤0.05），而含有未包封维 A 酸的样品的凝胶和溶液制剂的渗透系数分别为 K(p)=1.80±0.27 和 K(p)=0.73±0.12cm/s。纳米包封使药物在皮肤表面的滞留时间延长了两倍，从而延长了迟滞时间。
