Propylene glycol free 5% minoxidil lotion formulation: cosmetic acceptability, local tolerability, clinical efficacy and in-vitro skin absorption evaluations

Background: A new propylene glycol (PG)-free 5% minoxidil (Mnx) lotion has been recently commercialized. Aim of this study was to evaluate the acceptability/tolerability and clinical efficacy of 3-month application of this new PG-free Mnx lotion and the penetration of the active compound in a reconstructed human epidermis (RHE/Episkin) model in comparison with a PG Mnx 5% lotion. Methods: Thirty subjects of both sex with a diagnosis of AGA were enrolled in the trial. Cosmetic acceptability and clinical efficacy were evaluated after 4, 8 and 12 weeks of treatment. Global tolerability was evaluated at week 12. Cosmetic acceptability evaluation was assessed using a 7-item questionnaire using a 10-point scale score. Global Tolerability was evaluated with a 4-grade scale. Clinical efficacy was evaluated with a 5-grade scale. Skin absorption of PG-free Mnx was evaluated and compared with a PG Mnx solution using the Episkin model. Results: All subjects concluded the study. The 7-item questionnaire mean values were always <2 at each time-point evaluation, demonstrating high cosmetic acceptability/tolerability. No subjects reported burning, itching or redness sensations. Global Tolerability score mean±SD value was 1.7±0.4. Clinical efficacy scores were 0.4, 0.6 and 1.2 at week 4, 8 and 12, respectively. PG-free Mnx showed similar amount of absorbed dose in comparison with PG Mnx. Conclusions: This new PG-free lotion shows a very good cosmetic acceptability/tolerability profile. Clinical efficacy was also documented. The skin penetration of this formulation is comparable to the PG Mnx lotion, supporting the bioequivalence of the two products.