Influence of Excipients on Moisturizing Effect of Urea

Influence of creams with different urea concentrations on plantar skin hydration

INTRODUCTION

The skin is the body's outermost organ, and one of its main functions is to provide protection against potential infections. Hydration is related to the proper functioning of the skin, hindering the appearance of wounds or cracks which could lead to the occurrence of infections or other dermatological alterations. The skin of the foot is thicker than that of the rest of the body due to the load it supports, and it is more complicated to maintain. The intention of this study was to evaluate the efficacy of different concentrations of urea (5% and 20%) in hydrating the foot compared to a placebo cream.

METHODS

The study was carried out with 60 subjects of ages from 20 to 35 years in age. The experimental protocol was initiated by creating three randomized groups (1:1:1), each being treated with a different cream: placebo, 5% urea cream, and 20% urea cream. The examination was carried out using a non-invasive instrument (Corneometer CM 825®) that detects the skin surface hydration.

RESULTS

Analysis of the hydration of the different study zones according to the cream used showed no significant differences between the placebo and 5% urea for the first MTH and heel, but a significant difference for the fifth MTH. There were significant differences in all study areas between the placebo and 20% urea creams, but none between the 5% urea and 20% DISCUSSION/CONCLUSION: The conclusion drawn was that skin hydration was greater with the 20% urea cream versus the placebo, but there were no differences found when comparing either the 20% and 5% urea creams or the placebo and 5% urea creams.

Urea-containing topical formulations

Urea is a well-known moisturiser and keratolytic topical agent. As it is widely used in dermatology, several formulations at different concentrations have been marketed: lotions, creams, foams, ointments, gels and lacquers. Availability of different vehicles and concentration may vary in different countries, but in general products at low, medium and high urea concentration are accessible worldwide. The proper formulation should be chosen according to the disorder to treat, its severity, body areas involved and patients' preference.