International journal of pharmaceutics
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Randomized Controlled Trial Clinical Trial
Menthol facilitates the skin analgesic effect of tetracaine gel.
The aim of this study is to observe the effect of menthol on the percutaneous penetration and skin analgesic action of tetracaine gel (T-gel). Anesthetic gels containing 4% tetracaine in carbomer vehicle with and without menthol were prepared. The menthol penetration-enhanced gel conferred significantly higher diffusion of tetracaine across full-thickness mouse skin than non-penetration-enhanced gel, in a dose-dependent manner. ⋯ To determine the efficacy of menthol penetration-enhanced tetracaine gel in the management of pain, a double-blind, placebo-controlled, randomized controlled trial (RCT) design was used. The mean verbal pain scores (VPS) were significantly lower in volunteers treated with penetration-enhanced tetracaine gel than those in volunteers receiving non-penetration-enhanced tetracaine gel or placebo. Menthol improved the analgesic efficacy of the tetracaine 4% gel in part through enhanced percutaneous permeation.