chapter  13
22 Pages

The Chemistry of Ultraviolet Filters

Introduction 218

The Electromagnetic Spectrum 218

Effect of UV Radiation on the Skin 220

Classification of UV Filters 221

PABA and p-Aminobenzoates 224

Salicylates 226

Cinnamates 227

Benzophenones 228

Anthranilates 229

Dibenzoylmethanes 230

Camphor Derivatives 230

Miscellaneous Compounds 231

Mechanism of Sunscreening Action 231

Effect of Vehicle on the Efficacy of UV Filters 232

pH Effects on UV Filters 233

Effect of Emollients on the Efficacy of UV Filters 233

Effects on the Extinction Coefficient 235

The Future of UV Filters 235

Conclusions 237

References 238

INTRODUCTION

The recent evidence linking ultraviolet-A (UV-A) rays to serious damage beyond

the fashionable and sought-after tan is daunting (1). These and other important

findings have prompted the cosmetic industry to create new sunscreen products

that would afford the consumers more efficient protection. Since the cosmetic

industry began formulating a myriad of new sunscreen active agents into an

array of functional products, it has become necessary for the cosmetic chemist

to know more about the chemical structure and reactivity of UV filters and

their potential interaction with other ingredients in the sun care cosmetic

formulations.