Transport of Substances and Nanoparticles across the Skin and in Vitro Models to Evaluate Skin Permeation and/or Penetration

Abstract

Abstract. Nanotechnology can be used to modify the drug permeation/penetration of encapsulated substances, through the manipulation of many different factors, including direct contact with the skin surface and controlled release. In general, nanoparticles cannot cross the skin barrier, which can be explained by the cell cohesion and lipids of the stratum corneum, the outermost skin layer. The device most commonly used to study the transport of substances and nanoparticles across the skin is the Franz vertical diffusion cell, followed by the substance quantification in the receptor fluid or determination of the amount retained in the skin. Microscopy techniques have also been applied in skin penetration or permeation experiments. This chapter will present the fundamental considerations regarding the transport of encapsulated substances and/or nanoparticles across the skin, the experimental models applied in these studies and a review of the main studies reported in the literature in order to allow the reader to gain insight into the current knowledge available in this area.

The use of nanoencapsulation to decrease human skin irritation caused by capsaicinoids

“…The penetration of nanoparticles into the skin is more common for lipid nanoparticles but is not commonly observed for polymeric nanoparticles. 6 In our work, the ability of the nanoparticles to decrease skin irritation is probably explained by the controlled release properties of the nanocarriers.…”

“…Human skin was selected because of the high likelihood of an in vitro-in vivo correlation. 6 The human skin samples were obtained following plastic surgery, after securing informed consent from the patient. Intact skin (with an intact barrier) was used for the in vitro skin permeation experiment in order to allow a comparison with the skin irritation observed in vivo.…”

“…3,4 Regarding cutaneous use, these nanocapsules can act as a reservoir for lipophilic drugs, 5 modulating their penetration/permeation across the skin by controlling contact of the substances with the stratum corneum. 5,6 952 contri et al after application of retinoic acid was also determined using mouse skin and a visual scale. 7 Pople et al 9 encapsulated tacrolimus into lipid nanoparticles and observed a less irritating effect using the Draize skin patch test in rabbits when compared with a commercial formulation.…”

Nanotechnology-Based Cosmetics for Hair Care

“…Recent progress in nanotechnology allows for the development of carriers with enhanced ability to penetrate and permeate the skin. The stratum corneum, the lipid rich, tightly bonded outermost layer of the epidermis, is a direct barrier to ingredient penetration, preventing passage through the layers of the epidermis to the dermis [8]. While cosmetic products are not intended for systemic absorption, their efficacy depends on entry through this armor.…”

“…However, the presence of hair follicles significantly contributes to the penetration and permeation of topically applied nanosized particles. In the past, it was thought that appendageal offices occupy 0.1% of the skin surface [8]. However, new evidence has suggested that follicular distribution is body-region-dependent, with some body regions (i.e., forehead) harboring a significantly increased number of follicular orifices [10].…”