Characterizations and controlled drug release behavior of acyclovir-loaded starch-based microneedles patches for...

Transdermal drug delivery systems (TDDS) using microneedles (MNs) patches have shown promise for improved therapeutic outcomes. In this study, acyclovir (ACV)-loaded MNs patches for herpes simplex virus (HSV) therapy were prepared using mungbean starch (MBS), polyvinyl alcohol (PVA), and plasticizers (arginine and mannitol), and their physicochemical properties, ACV release behavior, antimicrobial activity, and biodegradation, cell viability, and antiviral efficacy were investigated. The MNs exhibited compression forces of 1.30 - 4.80 N/needle and a pyramidal square shape with a length of 620-640 μm, ensuring efficient skin penetration. The ACV release (%) from the ACV-loaded MNs patches during an artificial skin test was found to be 2.50 - 4.32 times higher than that from ACV-loaded biomaterial as the film-type formulation. Additionally, over 98.0 % of ACV was released from the prepared MNs patches within 80 min. The ACV release mechanism was analyzed using zero-order, first-order, Higuchi, Fickian diffusion, and Korsmeyer-Peppas models, which revealed a Fickian diffusion mechanism. Visualization of intradermal drug release were conducted using ACV- and riboflavin-loaded MNs patches on agar blocks and pig ears/agar block models. Biodegradability, cell viability, and antiviral studies further demonstrated the potential of MNs patches as a TDDS. These results suggest that the prepared MNs patches are promising candidates for transdermal HSV therapy.