Skin penetration of ultradeformable liposomes for topical drug delivery: CLSM as a tool of analysis

ALONSO, S. DEL VALLE; CALIENNI, M. NATALIA; MONTANARI, JORGE

Workshop; Imaging Techniques for Biotechnology and Biomedical Applications - Workshop; 2016

Ultradeformable liposomes (UL) of soyphosphatidylcholine and sodium cholate are a type of drug delivery nanosystem(Montanari et al. 2007). UL are capable to penetrate the stratum corneum of theskin impelled by the dehydration pressure caused by the transdermal humiditygradient (Cevc and Blume, 1992). The incorporation of drugs in UL improvesspecific-site delivery and aims to reduce collateral effects (Betancourt, etal., 2009). Therefore, it is crucial to determine if the novel formulationscontinue to penetrate the stratum corneum and release their content into theviable epidermis.UL loaded with the antitumoral drug 5-Fluorouracil (5FU) andtwo fluorescent dyes: Fluorescein Isothiocyanate (aqueous core of UL) and 1,2Dipalmitoyl-sn-glycero-3- phosphoethanolamine-N-(Lissamine? rhodamine Bsulfonyl) (membrane of UL), were non-occlusively applied on human skin in aSaarbrücken Penetration Model device 1 hour at 37ºC. Human skin explants wereobtained from abdominal surgery discards from caucasian 39 years old woman.After incubation, the full skin thickness was optically scanned at 6 μmincrements through the z-axis by confocal laser scanning microscopy (CLSM)until 60 µm profundity. Also, histological slides of incubated skin obtained bycryosectioning were studied by CLSM (Montanari, et al. 2010). Fluorescenceintensity of each image was obtained by Image-J software. The same histologicalslides were also subjected to hematoxylin and eosin staining in order to detectthe possible presence of histological alterations in the analyzed tissues,using light microscopy. 5FU-loaded conventional liposomes (without the borderactivator sodium cholate) were used as control of non-penetrant formulation.5FU delivery was indirectly observed both in the stratum corneum and in theviable epidermis. The dyes have penetrated together along the skin explant asit was evidenced with the CLSM analysis. However, in the histological slides,the lipophilic dye intensity was higher in the stratum corneum whereas thehydrophilic dye intensity was higher in the viable epidermis. Therefore, theformulation conserves its key feature of skin penetration at body temperatureafter encapsulation of 5FU.ReferencesBetancourt, T., et al., Controlled releaseand nanotechnology, in Nanotechnology in Drug Delivery, 2009, Springer. p.283-312.Cevc, G. and G. Blume, Lipid vesicles penetrate into intact skin owingto the transdermal osmotic gradients and hydration force. Biochim Biophys Acta,1992. 1104(1): p. 226-32.Montanari, J., et al., Photodynamic ultradeformableliposomes: Design and characterization. Int J Pharm, 2007. 330(1-2): p.183-94.Montanari, J., et al., Sunlight triggered photodynamic ultradeformableliposomes against Leishmania braziliensis are also leishmanicidal in the dark.J Control Release, 2010. 147(3): p. 368-76.