Читать книгу Cosmeceuticals - Группа авторов - Страница 41

Preservatives are perhaps the most controversial of all cosmeceutical ingredients. All currently available preservatives are made synthetically as no totally natural preservative blend has been created to date. No cosmeceutical can be sold commercially without refrigeration devoid of preservatives. However, preservatives have been blamed for everything from breast cancer to obesity to environmental damage. Without preservatives, the occlusive and emollient lipids in cosmeceutical formulations would rapidly oxidize, rendering the cream rancid, or bacterial contamination would render the water-soluble ingredients unsafe. Preservatives are the second most common allergenic group of substances found in cosmeceuticals behind fragrances [19]. However, the number of cases of irritant and allergic contact dermatitis are indeed small compared with the two necessary functions preservatives perform in cosmetics: spoilage prevention prior to purchase and prevention of contamination after purchase [20, 21]. Paraben esters are the most popular preservatives used in cosmetics as their sensitization and irritation potential is low when applied to healthy skin [22]. They are usually found in concentrations of 0.5% or less in the USA. Some of the “natural” cosmeceuticals use essential oils and fragrances with antimicrobial capabilities, such as oil of clove, cinnamon, eucalyptus, rose, lavender, lemon, thyme, rosemary, and sandalwood [23].