Sunscreen preparations

In vitro absorption-spectrophotometry techniques are available to assess a sunscreen s efficacy, but the preferred methods are in vivo procedures in which a small body site is irradiated with the desired wavelengths for different periods in the presence or absence of a uv protectant. Procedures vary from country to country to determine the incremental timing of the exposure that ultimately allows quantification via sun protective factor (SPE). In the United States, sunscreen preparations are considered OTC dmg products, and the SPE must be specified (54). Even in countries that do not identify these products as dmgs, SPE labeling has become customary. 

Perfumes, Flavors, Cosmetics, and Soap. Many naturally occurring esters in essential oils and some synthetic esters are important fragrance and flavor compounds (61,62). They are used in perfumes, flavors, cosmetics, soaps, detergents, and air fresheners. Benzyl, butyl, ethyl, methyl, and phenyl esters of benzoic acid are used as flavors, perfumes, and food preservatives. Glyceryl 4-aminobenzoate [136-44-7] and 2-ethyUiexyl 4-dimethylaminobenzoate [21245-02-3] are used in cosmetic sunscreen preparations. Alkyl esters of 4-hydroxybenzoic acid, called parabens, have been used under various names for fungus infections of the skin, and as preservatives in lotions and creams (101). Soap and cosmetic fragrances use large amounts of amyl and benzyl saHcylate. Benzyl saHcylate [118-58-1] is also used in deodorant sprays. 2-Ethylhexyl saHcylate [118-60-5] and 2-ethylhexyl 4-methoxycinnamate [5466-77-3] are used in sunscreen formulations (102). 

Q81 An ultrablock sunscreen preparation always has a sun protection factor of 30. Sunscreen preparations protect the skin from the damage associated with ultraviolet A (UVA). 

Sunscreen preparations tend to contain substances that protect the skin against sunburn caused by ultraviolet B (UVB) rays. UVA rays are associated v/ith long-term skin damage. Sunscreen preparations contain a variety of sun protection factors but not necessarily a factor of 30. 

Products known as UV absorbers, similar to the products used in sunscreen preparations, can be added to alcoholic lotions that almost eliminate this type of discoloration. Some companies use them as a matter of course in the manufacture of their finished perfumes and toilet waters. But they should not be added directly to the perfume compound. Many of the problems of discoloration in soap, for example, as by vanillin, are accelerated by exposure to light. 

Figure 1 Comparison of two hypothetical sunscreen preparations with a nominal SPF of 15 (----) 100% photostable (.) less photostable.

The photostability of sunscreens has been, since the 1990s, primarily a UV-A issue due to the fact that no agreed method was (and still isn t at this time) available to assess the protective capacity of a sunscreen preparation towards UV-A radiation. As in the early days, the photostability of the UV filter or the sunscreen preparation itself was tentatively used instead of a skin-related end point. 

The term "photostability" in the context of UV filters and sunscreen preparations is most often used in either of two ways ... 

Consequently, this kind of analysis may often lead to the premature disqualification of UV filters or UV filter combinations that are often found in sunscreen preparations. 

Optimally, the "analytical" and the "spectral" approaches should be combined. The two are complementary and together provide the most insight into the behavior of a UV filter or a sunscreen preparation. 

When studying UV filters or sunscreen preparations, it is useful and desirable to have some knowledge about the photochemical behavior of the components under study. It is the absence of this knowledge which, over the last two decades, has led to many misinterpretations and erroneous conclusions. 

Further, sunscreen preparations are usually packaged in materials, which are opaque to UV. The integrity of a sunscreen preparation can be checked by an in vitro SPF determination or more preferably and accurately by chemical analysis, e.g., HPLC (3) or spectrophotometrically. 

El 60(a) Solatene ) is a carotenoid and a vitamin substance widespread in plants and animals. In plants it is almost always associated with chlorophyll. It is a vitamin A precursor and exhibits strong vitamin A activity. It can be used in topical ultraviolet sunscreen preparations (but has not been shown to be effective). It can be given orally to reduce photosensitivity reactions in patients with erythro-poetic protoporphyria, and is sometimes tried as an adjunct in treating polymorphous light eruptions. It can be used orally as a dietary supplement also used as a yellow food colorant. 

Cinoiazepam [inn] is one of the [1,41 benzodiazepines, a BENZODIAZEPINE BINDING-SITE AGONIST, with most of its properties similar to diazepam. It has HYPNOTIC, ANTICONVULSANT and ANXIOLYTIC activity. It has been used orally to treat insomnia and anxiety, cinoxacin [ban, inn, jan, usan] (Clnobac ) is an ANTIMICROBIAL, One of a 4-quinolone family related to nalidixic acid, which, though symthetic, are sometimes described as ANTIBIOTICS. It can be used clinically as an ANTIBACTERIAL, mainly used orally for gut infections. Cinoxate [inn, usan] is a cinnamic acid derivative and can be used in topical sunscreen preparations. 

Use Softening agent, plasticizer, and perfume base. High absorption of UV light, low water solubility, low evaporation rate, and good solvent action make it useful in light-stable coatings and sunscreen preparations. 

In some instances it is not the material as applied to the skin that causes the allergic reaction, but a combination of the material and exposure to sunlight. In the late 1970s, the cause of an unusual number of cases of dermatitis in people using a sunscreen preparation was traced to the presence of 6-methylcoumarin, which was in the fragrance in the product... 

Tegner E (1976) Contact allergy to corticosteroids. Int J Dermatol 15 530-523 Thompson G, Maibach HI, Epstein J (1977) Allergic contact dermatitis from sunscreen preparations complicating photodermatitis. Arch Dermatol 113 1252-1253 Thormann J, Kaaber K (1978) Contact sensitivity to phenylbutazone ointment (butazolidine). Contact Dermatitis 4 235-236 Thormann J, Wildenhoff KE (1980) Contact allergy to idoxuridine. Contact Dermatitis 6 170-191... 

Widespread, found e.g. in carrots. Exhibits strong vitamin A activity. Used in ultraviolet sunscreen preparations. Yellow food colouring. Red-brown cryst. Mp 181°. Xmax 452, 484, 520 nm (CS2). Air-sensitive. 

A sunscreen preparation contains 2.50% by mass benzyl salicylate. If a tube contains 4.0 oz of sunscreen, how many kilograms of benzyl salicylate are needed to manufacture 325 tubes of sunscreen (2.6, 2.7)... 

Used in certain laxative preparations, more commonly in Europe. Extracts have been used in sunscreen preparations. ... 

Carrot root oil is used in certain sunscreen preparations and as a source of P-carotene and vitamin A. 

Extracts of both German and Roman chamomiles are used in cosmetics and body care products including bath preparations, hair dye formulas (for blond hair), shampoos, sunscreen preparations, mouthwashes, and others. The oils are used as fragrance components or active ingredients in soaps, detergents, creams, lotions, and perfumes. Use levels reported range from a low of 0.0005% in detergents to a maximum of 0.4% in perfumes considered... 

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