Dissolving Microneedles with Advanced Design–a Tool for Enhancing Skin Permeation of Naltrexone Hydrochloride

Dissolving microneedles (DMN) could be considered as a promising platform for transdermal delivery of naltrexone hydrochloride (NTX), providing a minimally inva-sive alternative to conventional administration routes. In the present study, DMN patches with an advanced design were developed via a two-step micromoulding tech-nique. The systems were composed of drug-free polyvinylpyrrolidone (PVP) and poly-vinyl alcohol (PVA) blend microneedle tips, combined with a drug-loaded backing layer based on PVP and the thermoresponsive polymer Poloxamer 407. The influence of polymer concentration into DMN tips and backing layer composition on morpholo-gy, mechanical properties, drug release and permeation was evaluated. Mechanical studies as well as SEM observation revealed that intermediate polymer concentration (formulation MN-20%/2:1), used for DMN tips preparation, provided optimal mi-croneedle geometry, superior structural integrity and penetration efficiency. Incorpo-ration of NTX into backing layer allowed high and uniform drug loading. In vitro per-meation studies demonstrated significantly enhanced NTX delivery from DMN sys-tems compared to simple matrix patches, with the thermoresponsive backing layer contributing to controlled drug release. These findings highlight the importance of polymer composition in DMN design and demonstrate the potential of the developed systems as an effective platform for transdermal delivery of NTX.