Fate of Poly-3-Hydroxybutyrate-co3-Hydroxyvalerate on Skin

Abstract

Transdermal drug delivery systems have become increasingly sophisticated over time. However, the greatest limitation for developing an effective drug delivery system is the highly impermeable outermost layer of the skin called the stratum corneum. Therefore, materials penetrating the skin must be of low molecular weight, and lipophilic. There are many techniques to safely pass the stratum corneum and one of the promising method of transdermal drug delivery is the use of micro and nano sized particles. The aim of this study was to develop three different micro and nano sized carriers to study their skin penetration and to judge their effectiveness within the skin. Polymeric micro/ nanocapsules carrying a fluorescent dye Nile Red, were prepared using poly(3-hydroxybutyrate-co 3-hydroxyvalerate) (PHBV) (5 %mol. hydroxyvalerate). The in vivo transdermal permeation of PHBV micro/nanoparticles were studied using a mouse model. According to the particle size analysis with Master Sizer and Zeta Potential Measurement System, the PHBV micro/nanocapsules were 1.9 µm, 426 nm and 166 nm in diameter. The particles were applied to healthy skin of the dorsal region of BALB/c mice. Penetration of the particles was determined by GC-MS analysis of the skin for PHBV. Scanning electron microscope (SEM) imaging was used to study their morphology. GC-MS results showed that the capsules penetrated into the skin in relation with their particle size, despite the highly impermeable outer skin layer. However, histology cross-section revealed that uncompromised skin could not penetrate; the transport of the polymeric particle was clearly impeded by the stratum corneum. It was thus shown in this study that control of penetration depth, and therefore, the target size within into the skin is possible by varying the size of the drug carrying nanocapsules.

Keywords

• transdermal drug delivery
• micro/nanocapsules
• polymeric carriers
• in vivo drug permeation