Controlled Release of Acyclovir from Starch-Based Microneedle Patches for Herpes Simplex Virus Therapy

Abstract

Transdermal drug delivery systems (TDDS) that employ microneedles (MNs) have demonstrated efficacy in disease therapy. In this study, we prepared acyclovir (ACV)-loaded MNs for herpes simplex virus (HSV) therapy using mungbean starch (MBS), polyvinyl alcohol (PVA), and plasticizers (arginine and mannitol) and investigated their characterization, ACV release behavior, antimicrobial activity, and antiviral activity. Mechanical strength and SEM analysis confirmed that the prepared ACV-loaded MNs demonstrated compression forces of 1.30 – 4.80 N/needle, and exhibited a pyramidal square needle shape with a length range of 620 – 640 μm, which is sufficient for effective skin penetration. The ACV release (%) from the ACV-loaded MNs 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 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 (RFV)-loaded MNs on agar blocks and pig ears/agar blocks. Additionally, biodegradation was evaluated using a soil degradation test. The antiviral activity results confirmed that the prepared ACV-loaded MNs are suitable for HSV therapy.

Keywords: Acyclovir-loaded starch-based microneedles, Drug release behavior, Drug release mechanism, Visualization of drug release, Antiviral activity