Atorvastatin-Loaded Dissolving Microarray Patches\nfor Long-Acting Microdepot Delivery: Comparison of Nanoparticle and\nMicroparticle Drug Formulations

The increasing popularity of prolonged-release dosage forms, owing\nto their ability to provide continuous drug release after administration,\nhas significantly improved patient compliance and overall quality\nof life. However, achieving prolonged release beyond 24 h frequently\nrequires the use of invasive methods, including injections or implants,\nwhich may prove challenging for people suffering from needle phobia.\nThis study introduces atorvastatin (ATR) microparticles (MPs) or nanocrystal\n(NCs) dissolving microarray patches (D-MAPs) as a noninvasive alternative\nfor intradermal drug delivery over a two-week period for the management\nof hyperlipidemia. The MP-loaded D-MAPs exhibited an average drug\nloading of 5.15 ± 0.4 mg of ATR per patch, surpassing the 2.4\n± 0.11 mg/patch observed with NC-loaded D-MAPs. Skin deposition\nstudies demonstrated the superior performance of MP D-MAPs, which\ndelivered 2.0 ± 0.33 mg of ATR per 0.75 cm<sup>2</sup> patch\nwithin 24 h, representing 38.76% of the initial amount of drug loaded.\nIn contrast, NC D-MAPs delivered approximately 0.89 ± 0.12 mg\nof ATR per 0.75 cm<sup>2</sup> patch at 24 h, equivalent to 38.42\n± 5.13% of the initial ATR loaded. Due to their favorable results,\nMP D-MAPs were chosen for an <i>in vivo</i> study using\nSprague–Dawley rats. The findings demonstrated the capacity\nof D-MAPs to deliver and attain therapeutically relevant ATR concentrations\n(>20 ng/mL) for 14 days after a single 24-h application. This study\nis the first to successfully demonstrate the long-acting transdermal\ndelivery of ATR using MP-loaded D-MAPs after a 24-h single-dose application.\nThe innovative D-MAP system, particularly when loaded with MP, arises\nas a promising, minimally invasive, long-acting substitute for ATR\ndelivery. This technology has the potential to improve patient compliance\nand therapeutic outcomes while also significantly advancing the field\nof transdermal drug delivery.