Moisturization efficacy tests

Grove, G.L., Noninvasive methods for assessing moisturizers, in Clinical Safety and Efficacy Testing of Cosmetics, Waggoner, W.C., Ed., Marcel Dekker, New York, 1990, chap. 7. 

Randomized controlled trials (RCTs) compare active therapy with placebo. Placebo should be as similar to the active therapy in appearance and feel as to be indistinguishable. This means that RCTs involving topical therapy are compared to the cream base, and the cream base most often has an independent function as a moisturizer. The potential effects of the cream base must be made explicit, as they may influence the efficacy of the product tested. By explicating the effect of the placebo arm of... 

In contrast with routine QC where a very limited number of samples are tested, a large number of product containers of each batch should be tested for critical analytical properties such as assay, activity or bioactivity, purity, degradation products, residual moisture, and reconstitution time. The purpose of extensive testing is to show that each pellet is typical and representative of the rest of the batch, which is a guarantee of product safety and efficacy as the patients are usually injected with the contents of a single container. 

The results of the immediate and the 15-minute post-treatment study are listed in Tables 6 and 7. The data indicate that moisture level of the inoculum source can influence bacterial counts and impact results of studies designed to test efficacy of an antibacterial product. Furthermore, the consistency of the results declines as subjects acquire bacteria from sources other than a broth culture. Because consumers are often exposed to bacteria by touching contaminated objects, use of a broth inoculate may not always be appropriate when assessing the... 

Halkier-Sorensen and Thestrup-Pedersen [40] utilized a cross-over study to evaluate the efficacy of a moisturizer (Locobase, Yamanouchi Europe B. V. Research Laboratories, Leiderdrop, The Netherlands) among cleaners and kitchen assistants during daily work. The population was divided into two groups 56 workers used the test moisturizer only on their hands for the first 2 weeks and no emollient during the subsequent 2 weeks, and vice versa (n = 55). The moisturizer prevented the development of skin dryness. Electrical capacitance (epidermal hydration) decreased significantly when the study subjects were not using the moisturizer but, unexpectedly, there was no increase in the TEWL rates or in skin temperature. 

Gabard B (1994) Testing the efficacy of moisturizers. In Eisner P, Berardesca W, Maibach HI (eds) Bioengineering and the skin water and the stratum corneum. CRC Press, Boca Raton,... 

In a more recent study, an increase of the skin microcirculatory patterns (skin temperature and blood flow/velocity in the skin capillaries) consequent to application of pure soluble collagen has been reported. These effects were related by the authors to a shortterm inhibition of the transepidermal water loss, causing indirect uptake of excess water by the biopolymers in the dermis and consequent increase of elasticity and pulsation efficacy of the small blood vessels (83). These tests are largely heterogeneous and the results obtained not comparable, being based on different exposure and evaluation methodologies however, all studies report only short-term moisturizing effects. 

---