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Monographs of fragrance chemicals and extracts that have caused contact allergy / allergic contact dermatitis
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
A woman applied a mixture of two popular sunscreens to her face, chest, and thighs. The active ingredient in one was amyl dimethyl PABA and in the other it was homosalate. Twenty-four hours later, the patient noted intense erythema and pruritus, limited to the areas pre-treated with the sunscreens. By 48 hours, there was massive swelling and vesiculation, with oozing of the face, and she could not retract her eyelids. Edema, vesiculation, and erythema were also present over the chest and thighs. Photopatch testing showed positive reactions to the two sunscreens and to 6-MC. Unirradiated patch tests were negative, as were controls. Three patients known to be sensitive to 6-MC were also tested with the sunscreens and had strongly positive photopatch test reactions. High-pressure liquid chromatography analysis of the two sunscreens revealed 6-MC levels of 0.032% in one and 0.2% in the other (19).
Novel UV Filtering Agents for Next-Generation Cosmetics: From Phytochemicals to Inorganic Nanomaterials
Published in Madhu Gupta, Durgesh Nandini Chauhan, Vikas Sharma, Nagendra Singh Chauhan, Novel Drug Delivery Systems for Phytoconstituents, 2020
Cinnamates, salicylates octocrylene, and ensulizole are also active organic UV protective agents. Cinnamates are octinoxate (octyl methoxycinnamate [OMC]) and cinoxate (2-ethoxyethyl-methoxycinnamate). OMC is a potent UVB absorber and is the most frequently used sunscreen ingredient. Salicylates are weak UVB absorbers, and they are generally used in combination with other UV filters. Both octisalate and homosalate are water insoluble that leads to their high substantivity, which is the ability to retain its effectiveness after exposure to water and perspiration. Otocrylene has an excellent safety profile with low irritation, phototoxicity, and photoallergic potential and is used in combination with other UV absorbers to achieve higher SPF formulas and to add stability. Ensulizole or phenylbenzimidazole sulfonic acid is water soluble, and it is used in products formulated to feel lighter and less oily, such as daily use cosmetic moisturizers. It is a selective UVB filter, allowing almost all UVA transmission.
Understanding Fragrance: From Chemistry to Emotion
Published in Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters, Cosmetic Formulation, 2019
The simplest formulation using fragrances is an alcoholic dilution to prepare a perfume. This consists of ethanol (around 80% concentration), water and the fragrance oil. As the final packaging is usually transparent glass, stabilizers are added to protect against interaction with sunlight and prevent any visual change (colour, precipitation, cloudiness, etc.) that will result in consumer rejection of the product. Typical stabilizers are UV filters (benzophenone-3, homosalate and others), chelating agents to reduce availability of heavy metals (ethylenediaminetetraacetic acid [EDTA]) and antioxidant agents (butylated hydroxytoluene [BHT], citric acid). Many perfumes contain colourants or dyes that can add further complexity as some colourants, such as red and blue dyes, have limited photostability requiring a better stabilization system. Perfumes are best prepared by first adding the fragrance oil to alcohol, followed by the addition of the water and other ingredients. The final solution is then chilled to around 5°C and filtered to remove any solid residues or solid material that was not properly solubilized, and also to avoid future precipitation.
Prospects of topical protection from ultraviolet radiation exposure: a critical review on the juxtaposition of the benefits and risks involved with the use of chemoprotective agents
Published in Journal of Dermatological Treatment, 2018
Nilutpal Sharma Bora, Bhaskar Mazumder, Pronobesh Chattopadhyay
Octisalate, homosalate, and trolamine salicylate fall within the class of salicylates which is the weakest organic UVB agents. These ingredients have been known to posses very good safety profiles and are used in conjugation with other sunscreens in relatively high concentrations to augment UVB protection. The photodegradation of other active sunscreen ingredients can be reduced with salicylates such as homosalate and octisalate. These are available in the form of hydrophobic liquids which can serve as solvents for other sunscreens as well as provide water repellent properties (64). Alternatively, the salicylate trolamine salicylate is water soluble which is extensively found in hair care products.
Dispelling myths about sunscreen
Published in Journal of Dermatological Treatment, 2022
Sabrina Lichon Bennett, Amor Khachemoune
The U.S. FDA regulates sunscreen products and classifies them as over-the-counter drugs. In 2019, FDA proposed a new rule describing which sunscreen ingredients are generally recognized as safe and effective (GRASE) (41). The two ingredients found in physical sunscreens, titanium dioxide and zinc oxide, are currently classified as GRASE as studies have shown them to be safe and not systemically absorbed (41–43). Two ingredients that are not GRASE include PABA and tolamine salicylate, which you cannot find in any sunscreen sold in the United States (3,42). Some ingredients found in chemical sunscreens do not have sufficient data yet to determine their GRASE classification, and the proposed rule asks for more data to be provided to the FDA before ruling on their GRASE classification (41). Since the proposed rule, there have been two studies looking at the systemic absorption of certain chemical sunscreens (44–45). The first study looked at the systemic levels of four chemical UV filters (avobenzone, oxybenzone, octocrylene, and ecamsule) after maximal use conditions (application four times a day), while the second study looked at systemic levels of seven chemical UV filters (avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate) after single application. Both studies found systemic levels of these UV filters exceeded the FDA threshold for safety testing (plasma concentration >0.05 ng/mL) under both protocols (44–45). While these ingredients are systemically absorbed, the FDA has not ruled these ingredients unsafe and does not explicitly say to stop using sunscreens with these ingredients as there is not enough data on the health effects of these ingredients (3). If individuals are concerned about the possible health effects of these ingredients, we recommend choosing physical sunscreen as the current studies show them to be safe (38–39).