Codelivery of hydrophilic and hydrophobic drugs in a microneedle patch for the treatment of skin pigmentation

When overexposed to ultraviolet B (UVB) irradiation, skin can cause a series of abnormal reactions, such as excessive pigmentation and solar elastosis. In order to better treat the skin after overexposed to UVB, we designed a dissolving microneedles (MNs) loading hydrophilic ascorbic acid and hydrophobic vitamin A palmitate to achieve codelivery. Here, we confirmed that MNs had enough mechanical strength to insert the skin and two drugs were delivered subcutaneously in sequence in vitro. In white guinea pigs, surface observation and histological observation results confirmed that two drugs by MNs transdermal delivery were better than topical administration in the treatment of UVB-damaged skin. The MNs provide a method of loading different drugs into the needles and advance the development of transdermal drug delivery.