Stabilized ascorbic acid derivatives in microneedle systems: a targeted approach for dermatological anti-aging and pigmentation correction

Abstract

Abstract Background Skin aging and hyperpigmentation disorders, primarily driven by oxidative stress, pose major dermatological challenges. Ascorbic acid plays a crucial role in collagen synthesis and modulation of melanogenesis; however, its clinical utility is restricted due to chemical instability and poor transdermal permeability. Objective This study aimed to develop and characterize dissolving microneedles (MNs) composed of polyvinyl alcohol (PVA) and glycerol for enhanced dermal delivery of stabilized ascorbic acid derivatives—ascorbyl palmitate (AP) and ascorbyl glucoside (AG). Methods MNs (11 × 11 array, 600 μm height) were fabricated via solvent casting using varying concentrations of PVA. The optimized formulation (12% PVA) was evaluated for mechanical strength, drug loading, insertion depth, and physicochemical stability using tensile testing, microscopy, FTIR spectroscopy, and thermal analysis. Antioxidant activity and in vitro drug release profiles were also assessed. Results and Discussion The optimized MNs exhibited robust mechanical properties (tensile strength: 10.17 ± 1.44 MPa) and uniform drug loading (AP: 50 ± 2.14 µg/patch; AG: 70 ± 1.24 µg/patch). Penetration studies confirmed successful skin insertion to approximately 508 μm depth with maintained structural integrity. FTIR and thermal analyses revealed amorphous solid dispersion without chemical interactions. Both AP-MNs and AG-MNs retained antioxidant activity post-encapsulation (IC₅₀: 25.4 ± 2.9 µg/mL and 62.1 ± 3.7 µg/mL, respectively) and demonstrated sustained release over 24 h (98 ± 2.41% for AP-MNs; 95 ± 1.32% for AG-MNs). Conclusion PVA-glycerol dissolving microneedles effectively delivered ascorbic acid derivatives transdermally, maintaining stability and antioxidant function. These MN systems present a promising, minimally invasive platform for anti-aging and hyperpigmentation therapies warranting biological validation to confirm therapeutic efficacy.