Combination of microneedles with PLGA nanoparticles as a potential strategy for topical drug delivery

Penetration of PLGA nanoparticles in the hairless mouse skin petreated by microneedles was studied in vitro using nanoparticles containing coumarin 6 and R-phycoerythrin (R-PE) as fluorescent probe. Confocal laser scanning microscopy (CLSM) was used to visualize the distribution of nanoparticles and the high performance liquid chromatography (HPLC) was utilized to quantify the amount of the nanoparticles. The CLSM images revealed that nanoparticles (diameter 160.1 +/- 1.97nm) could penetrate into the skin through the microconduits created with microneedles and reach the depth of more than 42.19 mu m. The quantitative results showed that the amount of nanoparticles deposited in the skin increased by microneedles was about twice that in the control group in a period of 48h. However, the nanoparticle was not able to reach the receptor compartment. In additional, the penetration and the distribution of nanoparticles was significantly influenced by the particle size (diameter ranged from 160.1 +/- 1.97nm to 288.2 +/- 6.62nm). These results suggested that the combination of PLGA nanoparticles with microneedles could be a useful method to increase topical drug delivery and improving therapy by supplying drug reservoirs to the skin.