ABSTRACT
Introduction 293
Specific Aspects of Topical Formulations 294
SC and Hydration 294
Role of Physiological Lipids 296
Barrier Protection and Barrier Recovery 297
Protective Creams with Special Ingredients 300
Application 300
Adverse Effects and Contraindications 301
Conclusion 301
References 302
INTRODUCTION
The stratum corneum (SC) is a very resilient tissue, resulting from the cornified
envelope of individual corneocytes, which is highly resistant to both physical and
chemical assaults, and from the interdigitation of adjacent corneocytes, as well
as from the riveting of adjacent corneocytes via specialized desmosomes
(corneodesmosomes). An interconnected network of structural proteins disperses
the force of external physical insults laterally throughout the skin. SC elasticity
(1) is also influenced by the extent of hydration of corneocyte cytosolic proteins,
a variable that is regulated by the hygroscopic breakdown products of filaggrin
(2), by the sebaceous gland-derived glycerol (3), resulting from high rates of
triglyceride turnover (4), and by changes in external humidity (5,6). SC proteins,
lipids (especially, ceramides), glycerol, and low molecular weight byproducts of
keratohyalin (filaggrin) catabolism, known as natural moisturizing factors
(NMF), bind and retain water in the SC, thereby maintaining its elasticity (4).
