Atorvastatin-Loaded Dissolving Microarray Patches for Long-Acting Microdepot Delivery: Comparison of Nanoparticle and Microparticle Drug Formulations

The increasing popularity of prolonged-release dosage forms, owing to their ability to provide continuous drug release after administration, has significantly improved patient compliance and overall quality of life. However, achieving prolonged release beyond 24 h frequently requires the use of invasive methods, including injections or implants, which may prove challenging for people suffering from needle phobia. This study introduces atorvastatin (ATR) microparticles (MPs) or nanocrystal (NCs) dissolving microarray patches (D-MAPs) as a noninvasive alternative for intradermal drug delivery over a two-week period for the management of hyperlipidemia. The MP-loaded D-MAPs exhibited an average drug loading of 5.15 ± 0.4 mg of ATR per patch, surpassing the 2.4 ± 0.11 mg/patch observed with NC-loaded D-MAPs. Skin deposition studies demonstrated the superior performance of MP D-MAPs, which delivered 2.0 ± 0.33 mg of ATR per 0.75 cm² patch within 24 h, representing 38.76% of the initial amount of drug loaded. In contrast, NC D-MAPs delivered approximately 0.89 ± 0.12 mg of ATR per 0.75 cm² patch at 24 h, equivalent to 38.42 ± 5.13% of the initial ATR loaded. Due to their favorable results, MP D-MAPs were chosen for an <i>in vivo</i> study using Sprague-Dawley rats. The findings demonstrated the capacity of D-MAPs to deliver and attain therapeutically relevant ATR concentrations (>20 ng/mL) for 14 days after a single 24-h application. This study is the first to successfully demonstrate the long-acting transdermal delivery of ATR using MP-loaded D-MAPs after a 24-h single-dose application. The innovative D-MAP system, particularly when loaded with MP, arises as a promising, minimally invasive, long-acting substitute for ATR delivery. This technology has the potential to improve patient compliance and therapeutic outcomes while also significantly advancing the field of transdermal drug delivery.