Both methodologies present similar aspects on the procedure, but they present important divergences in the experimental design and in the way of evaluating the result, generating different responses.
For COLIPA methodology, first, it is necessary to determine the static SPF on dry skin and then determining the SPF after water immersion. The water resistance evaluation is made through the ration between the result obtained after the immersion and the result obtained on dry skin (static SPF). In general, for a sunscreen to be considered with water resistance, the mean SPF value after the water immersion should be at least 50% of the static SPF, taking into consideration the variation obtained in the clinical study.
For the FDA methodology, it is possible to directly determine the SPF after water immersion, without the static SPF, since there is the demand that the SPF on the label is the one obtained after the immersion.
Allergisa has 4 bathtubs with controls of the parameters of the water, such as agitation (flow), temperature, pH, conductivity and hardness, which might affect the SPF after immersion results. The bathtubs are individual and projected for more comfort to the subjects, they are equipped with televisions for entertainment.
We also take part in proficiency tests (interlaboratorial), in order to assure that our results are always close to the main labs in the world.
Our studies follow strict protocols and standardized by national and international resolutions or validated within the most strict quality concepts.SEE ALL SPF SERVICES