Sonophoretic acceleration of degradation process for vaterite particles delivered into the hair follicles

Intrafollicular drug delivery is beneficial in terms of both localized therapy of relevant skin disorders and systemic transportation of bioactive molecules. Vaterite particles are capable of loading and delivering various substances to hair follicles. Possibility to control the duration of their intrafollicular degradation can improve such a particulate delivery system. Here, we propose the use of sonophoresis (1 MHz, 1 W/cm$^{2}$) to accelerate the resorption of vaterite carriers inside the hair follicles of rats in vivo. The effect of sonication is demonstrated utilizing optical coherence tomography monitoring of the skin and scanning electron microscopy investigation of the plucked hairs. A nine-minute post-treatment of skin in the site of particle delivery allowed us to almost halve the time of their degradation.