(124e) Stratum Corneum Microstructure And Implications To Size-Dependent Penetration For Transdermal Delivery

Authors: 
Xu, P., Tulane University
Tan, G., Tulane University
Lawson, L. B., Tulane university
He, J., Tulane University
Clements, J. D., Tulane University School of Medicine
Papadopoulos, K. D., Tulane University
John, V. T., Tulane University


Real time monitoring of penetration through the stratum corneum using confocal laser scanning microscopy is correlated with imaging of skin microstructure using cryo-scanning electron microscopy. The z-series dynamic penetration profiles of fluorescent molecules in the stratum corneum were systematically correlated with cross-sections of skin. Fluorescein salt, fluorescent labeled BSA (~6 nm) and polystyrene latex beads (~30 nm) were used as model penetrants to characterize transport through freestanding stratum corneum. Small molecule fluorescein salt penetrates the stratum corneum within 10 minutes. FITC-BSA is most concentrated in the stratum corneum and detectable in the upper epidermis after 2 hours. Thirty-nanometer latex beads are not transported across the stratum corneum in 2 hours. The penetration of selected molecules or nanoparticles is size-dependent. Freestanding stratum corneum is suitable for penetration studies relevant to vaccine antigen permeation and presentation to underlying dendritic cells of the immune system.