Maestrelli Francesca, González-Rodríguez Maria Luísa, Rabasco Antonio Maria, Mura Paola
Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Florence, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy.
Int J Pharm. 2005 Jul 14;298(1):55-67. doi: 10.1016/j.ijpharm.2005.03.033.
Multilamellar vesicle (MLV) liposomes containing ketoprofen-cyclodextrin complexes intended for drug topical delivery were prepared, with the aim of simultaneously exploiting the favourable properties of both carriers. Drug complexes with beta-cyclodextrin (betaCyd) and hydroxypropyl-betaCyd (HPbetaCyd), prepared by coevaporation and sealed-heating methods, were characterised by differential scanning calorimetry, hot stage microscopy, scanning electron microscopy and tested for dissolution properties. The coevaporated system with HPbetaCyd was the most effective, enabling an about 11-fold increase in drug dissolution. Drug and drug-Cyd systems were incorporated in MLV liposomes prepared by the thin layer evaporation technique. All liposomal formulations were characterised for encapsulation efficiency, particle size and morphology, using dialysis, light scattering and transmission electron microscopy techniques, respectively. MLV formation was negatively influenced by the presence of Cyd; nevertheless, it was possible to prepare stable MLVs containing ketoprofen-Cyd complexes. The presence of the Cyd complex affected MLV dimensions but not their lamellar structure. The complex with HPbetaCyd, in virtue of its greater stability than the betaCyd one, allowed higher percentages of encapsulation and gave rise to more stable MLV systems. Permeability studies of drug and drug-Cyd complexes, as such or incorporated in liposomes, performed both across artificial membranes and rat skin, highlighted a favourable effect of Cyd on drug permeation rate, due to its solubilizing action; by contrast, unexpectedly, no skin-permeation enhancer property of liposomes has been evidenced. Confocal laser scanning microscopy studies carried out with the rhodamine-Cyd complex as fluorescent marker, confirmed such results, showing that the label permeated deeper across rat skin layers when it was in solution than when entrapped in liposomes.
制备了含有酮洛芬 - 环糊精复合物的多层囊泡(MLV)脂质体,用于药物局部递送,目的是同时利用两种载体的有利特性。通过共蒸发和密封加热法制备的与β-环糊精(βCyd)和羟丙基 -β-环糊精(HPβCyd)的药物复合物,通过差示扫描量热法、热台显微镜、扫描电子显微镜进行表征,并测试其溶解性能。与HPβCyd的共蒸发体系最有效,使药物溶解增加约11倍。药物和药物 - Cyd体系被包封在通过薄层蒸发技术制备的MLV脂质体中。分别使用透析、光散射和透射电子显微镜技术对所有脂质体制剂的包封效率、粒径和形态进行表征。Cyd的存在对MLV的形成有负面影响;然而,仍有可能制备含有酮洛芬 - Cyd复合物的稳定MLV。Cyd复合物的存在影响MLV的尺寸,但不影响其层状结构。与HPβCyd的复合物由于其比βCyd复合物具有更高的稳定性,允许更高的包封百分比,并产生更稳定的MLV系统。对药物和药物 - Cyd复合物本身或包封在脂质体中的情况进行的跨人工膜和大鼠皮肤的渗透性研究表明,由于其增溶作用,Cyd对药物渗透速率有有利影响;相比之下,出乎意料的是,未证明脂质体具有皮肤渗透促进剂特性。以罗丹明 - Cyd复合物作为荧光标记进行的共聚焦激光扫描显微镜研究证实了这些结果,表明该标记物在溶液中时比包封在脂质体中时能更深地渗透过大鼠皮肤层。