Background and Objectives
Nanotechnology may increase the speed of penetration into the skin. This study evaluated the efficacy, safety, and pharmacokinetics of a novel topical anesthetic nanocapsule formulation (2 g) containing 2.5% lidocaine and 2.5% prilocaine (nanorap—test formulation) compared to placebo (control formulation) in skin types I–III patients of both sexes submitted to the ablative fractional CO2 laser treatment.
Methods
The patients (n = 120) included in this double‐blind, single‐center, randomized trial, received topical application of 2 g of the test formulation (50 mg lidocaine + 50 mg prilocaine) and placebo on the forehead region. Efficacy was assessed as pain sensation in four quadrants of each side of the forehead using a visual analogue scale immediately (0 min) and at 30, 60, and 90 minutes after laser application compared to placebo. The safety and tolerability of the test product were evaluated based on the occurrence of systemic adverse events as well as the occurrence of immediate and late skin reactions. Pharmacokinetic evaluation was performed in plasma of eight patients using a validated LC‐MS/MS method for drugs quantification.
Results
Nanorap induced a clinically significant reduction in the pain assessment at all evaluated times (57.2%, 41.6%, 38.6%, and 37.3% at 0, 30, 60, and 90 minutes after drug application, respectively. Mean values of Cmax were 14.20 and 5.36 ng/ml and tmax were 3.5 and 1.8 hour for lidocaine and prilocaine, respectively. No systemic adverse events were observed.
Conclusion
The nanorap formulation demonstrated a clinically and statistically significant efficacy providing analgesia after the ablative fractional CO2 laser therapy in the investigated patients, when compared to placebo. The product also presented good safety and tolerability. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.