Graphene oxide-enhanced dissolvable microneedles for transdermal delivery of alendronate: Augmented permeation and antibacterial activity

Osteoporosis treatment using alendronate (ALN) is limited by poor oral bioavailability and gastrointestinal side effects. To address this limitation, this study developed a graphene oxide (GO)-enhanced soluble microneedle (MN) system for transdermal administration of ALN to treat osteoporosis. The MNs were fabricated from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) using a two-step casting method, forming a drug-loaded core–barrier outer layer. The incorporation of GO significantly improved mechanical strength, with penetration efficiency reaching 66∼88%, and enhanced swelling capacity (PP/GO-ALN swelling ratio: 299%). In vitro release studies showed no significant difference between PP-ALN and PP/GO-ALN MNs in a dialysis bag model, while ex vivo skin permeation demonstrated that PP/GO-ALN MNs achieved significantly higher cumulative drug permeation (1069.53 µg/cm 2 ) over 24 h compared to PP-ALN MNs (712.89 µg/cm 2 ). Furthermore, GO conferred notable antibacterial activity, and the PP/GO-ALN formulation synergistically promoted osteoblast proliferation (cell viability: 107.42%, p < 0.05). These findings demonstrate that the GO-ALN MN system possesses mechanical properties, transdermal delivery, antibacterial effects, and biocompatibility. It provides a highly promising non-invasive strategy for the treatment of osteoporosis.