Enhancing the transdermal delivery of rigid nanoparticles using the simultaneous application of ultrasound and sodium lauryl sulfate

The potential of rigid nanoparticles to serve as transdermal drug carriers can be greatly enhanced by improving their skin penetration Therefore the simultaneous application of ultrasound and sodium lauryl sulfate (referred to as US/SLS) was evaluated as a skin pre-treatment method for enhancing the passive transdermal delivery of nanoparticles We utilized inductively coupled plasma mass spectrometry and an Improved application of confocal microscopy to compare the delivery of 10- and 20-nm cationic neutral and anionic quantum dots (QDs) into US/SLS-treated and untreated pig split-thickness skin Our findings include (a) similar to 001% of the QDs penetrate the dermis of untreated skin (which we quantify for the first time) (b) the QDs fully permeate US/SLS-treated skin (c) the two cationic QDs studied exhibit different extents of skin penetration and dermal clearance and (d) the QD skin penetration is heterogeneous We discuss routes of nanoparticle skin penetration and the application of the methods described herein to address conflicting literature reports on nanoparticle skin penetration We conclude that US/SLS treatment significantly enhances QD transdermal penetration by 500-1300% Our findings suggest that an optimum surface charge exists for nanoparticle skin penetration and motivate the application of nanoparticle carriers to US/SLS-treated skin for enhanced transdermal drug delivery (C) 2010 Elsevier Ltd All rights reserved