Radiofrequency Microneedling-Mediated Enhancement in Percutaneous Delivery of Topical Triamcinolone Acetonide: An In Vivo Quantitative Study

Background: The stratum corneum (SC) limits the efficacy of topical corticosteroids. Radiofrequency microneedling (RFMN) may enhance drug delivery; however, quantitative in vivo human data remain limited. Objective: To evaluate RFMN-assisted delivery of topical triamcinolone acetonide (TAC) and determine optimal device parameters. Methods: In this prospective intra-individual study, five healthy volunteers underwent TAC application followed by RFMN on volar forearms. Two insertion depths (0.5 and 2.5 mm) and three RF energy levels (0, 390, and 750 mJ) were assessed. TAC uptake into the SC was quantified after 6 h using tape stripping and UPLC-PDA. Results: RFMN significantly enhanced TAC absorption compared with topical application alone. The highest uptake was observed at 2.5 mm insertion depth without RF energy (3.5-fold increase). At 0.5 mm depth, only moderate RF energy (390 mJ) improved penetration (2.3-fold), whereas higher energy showed no benefit. TAC distribution profiles demonstrated increased drug deposition primarily in superficial SC layers. Conclusions: Insertion depth is the primary determinant of RFMN-assisted drug delivery, while RF energy plays a secondary, context-dependent role. RFMN represents a promising strategy to enhance topical corticosteroid delivery with potential clinical applications in inflammatory dermatoses and scar modulation.