Dendrobium polysaccharide-based microneedles loaded with Celosia cristata flavonoids and adapalene nanoparticles for efficacious treatment of acne vulgaris.

Acne vulgaris is a common chronic inflammatory skin disorder primarily caused by the overgrowth of Propionibacterium acnes (P. acnes). However, the therapeutic efficacy of traditional drugs is often limited due to their inability to penetrate the stratum corneum. Microneedles (MNs) are designed to penetrate the stratum corneum, enabling direct drug delivery to the epidermis. In this study, a new Dendrobium polysaccharide-based composite microneedle (DOP/CCF/PLGA@Adap-MN) delivery system was developed. Dendrobium polysaccharide (DOP) was utilized as the microneedle matrix, loaded with the Celosia cristata flavonoids (CCF) and poly(lactic-co-glycolic acid) adapalene nanoparticles (PLGA@Adap NPs). DOP not only enhanced the mechanical properties and transdermal efficiency of the microneedles but also provided intrinsic anti-inflammatory activity. CCF effectively inhibited the growth of P. acnes, while PLGA@Adap NPs slowly released adapalene to promote acne healing. In vivo studies using a P. acnes-induced mice model demonstrated that this microneedle system effectively reduced skin swelling, inhibited bacterial growth, and decreased inflammatory cell numbers in the skin. The use of bioactive DOP as a microneedle matrix, combined with sustained-release technology, provides a multifaceted and synergistic approach to acne treatment.