ABSTRACT
As a novel transdermal drug delivery technology of minimally invasive, safe and efficient, microneedles have received increasing attention. The microchannels formation by microneedles onto the skin is a prerequisite and key for microneedles to deliver drugs. However, there is still a lack of systematic evaluation in skin microchannels. This review summarized influencing factors and evaluation methods in microchannels formation and healing by microneedles, including geometric parameters, materials for preparation, drugs, penetration parameters, differences among the skin of subjects, and presence or absence of occlusion. This review provides reference for other scholars to further study the effectiveness and security of microneedle applications.