In 1997, Wiechers1 introduced the concept of relative performance measurement to compare the moisturization of several neat emollients. The capacitance of skin treated with test products was measured by a corneometer and compared with glycerin-treated skin (defined as 100%) and untreated skin (defined as 0%) at given intervals, normally 6 hr after application. As one might expect, this test showed that all emollients were not the same in their capacity to moisturize skin. Emollients offered either low moisturization performance (0–30% relative performance moisturization (RPM)), medium RPM (30–70%), high RPM (70–100%), or excellent RPM (> 100%).1 Two structurally similar emollients interestingly imparted completely different moisturization performance: isopropyl isostearate (IPIS), with an RPM of 100%; and isostearyl isostearate (ISIS) with a score of only 15%, as illustrated in Figure 1.
Orthorhombic Phase Stabilization for Internal Occlusion: A New Mechanism for Skin Moisturization
Jul 16th, 2013