Elaboration, characterization, and stability study of a sunscreen emulsion for use as a towelette application in...

The World Health Organization (WHO) estimates that as much as 80% of the solar radiation that an adult receives throughout his/her life is received during the first 18 years (1). Skin protection against harmful solar radiation during this early stage of life is therefore a highly important factor in the prevention of future skin-related diseases. In this respect, recent developments in pediatric dermatology and cosmetic technology have led to remarkable improvements in child skin protection products. However, in spite of these scientific breakthroughs, many currently available commercial sunscreen formulations have not been well received by the general public, due to inadequate sensory properties, chemical instability, undesirable side effects, and low effectiveness. These disadvantages are not only attributable to the formulations themselves, active principle, and excipients, but also, to a large extent, galenic aspects. The objective of this work was to develop and characterize a sunscreen emulsion for pediatric use, using a towelette as vehicle, to overcome problems of ineffectiveness and formulation instability, and to improve skin-sensory properties. The composition of the towelette, the emulsion, and the presentation format were selected on the basis of the differences between children's and adult skin. In order to evaluate the chemical stability of the formulation, a study of the organoleptic, physicochemical, microbiological, and rheological characteristics was carried out at 4°, 25°, and 40°C over a period of 30 days. Tests were performed on both the sunscreen emulsion only and the same formulation impregnated within a towel, to test the influence the towel may have on the stability of the emulsion.