## ABSTRACT

Glycerin-Based Moisturizing Lotion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 28.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370

Lipids in the stratum corneum (SC) account for only about 15% of its weight, yet they constitute the primary barrier of the skin,1-5 forming a protective sheath that shields us from desiccation and environmental insults.6 These barrier lipids exist in the SC intercellular space as highly organized lamellar bilayers that are readily visualized by the marriage of transmission electron microscopy (TEM) with RuO4 staining.7,8 The lamellar organization consists of a unique pattern of alternating electron-lucent and electron-dense lamellae forming repeating structures7-10 that are often referred to as Landmann units.10 This lamellar structure appears throughout most of the SC thickness,

Loden “2134_C028” — 2005/9/29 — 21:20 — page 352 — #2

Dry Skin and Moisturizers: Chemistry and

FIGURE 28.1 Normal structure of the lipid lamellae in the intercellular space. Shown are three Landmann units separating the darkly staining corneocytes above and below this intercellular space. Bar = 25 nm.