When it comes to sun protection, the science is clear. Health experts agree that using sunscreen is important during outdoor summer activities to protect the skin from the sun’s damaging ultraviolet rays. Too much sun exposure can cause sunburns, premature skin aging and skin cancer.
A sunscreen labelled “broad spectrum” provides UV protection across both the UVB and UVA range. Most of the sunscreen manufacturers consider SPF (Sun Protection Factor) while formulating sunscreen which depends on the active ingredients used in the formulation, which are basically responsible for providing protection against Sunlight.
Sunscreen agents are basically categorized into inorganic and organic UV filters which have specific mechanisms of action upon exposure to sunlight. Inorganic agents reflect and scatter light, while organic blockers absorb high-energy UV radiation. Recently, hybrid materials combining properties of organic and inorganic compounds have attracted the attention of scientists as a promising sunscreen agent. Remarkably, botanical agents, which contain large amounts of antioxidant compounds, can be used as inactive ingredients to protect the skin against adverse effects (e.g., photo aging, wrinkles, and pigment).
Further, organic blockers are classified into either UVA (anthranilates, dibenzoylmethanes, and benzophenones) or UVB filters (salicylates, cinnamates, para-aminobenzoic acid (PABA) derivatives, and camphor derivative). These agents show outstanding safety and aesthetic properties, compared to inorganic UV filters. Besides, they are mostly used in combination to provide broad-spectrum absorption, as well as increased SPF values. Nevertheless, the combination is limited in selecting the appropriate UVA/UVB filters to avoid possible negative interactions between the combining agents.
Inorganic blockers have been approved to protect human skin from direct contact with sunlight by reflecting or scattering UV radiation over broad spectra. The current agents are ZnO, TiO2, FexOy, calamine, ichthammol and talc. Although they are generally less toxic, more stable, and safer for human than those of organic ingredients, they are visible due to white pigment residues left on the skin and can stain clothes.
The hybrid materials are two half-blended materials intended to create desirable functionalities and properties. They are constituted of organic components mixed with inorganic components at the molecular or nano scale. The combination creates ideal materials with a large spectrum and high physicochemical properties.
Majority of the organic as well as inorganic sunscreen ingredients are effective against UVB. There are very few sunscreen ingredients like Avobenzone, PBSA, and Ethyl Hexyl Triazone which are effective against UVA.
An ideal Sunscreen agent should be safe, nontoxic, chemically inert, non-irritating, and fully protect against broad spectrum that can prevent photo carcinogenesis and photo aging. However, they also have negative effects, including contact sensitivity, estrogenicity, photo allergic dermatitis, and risk of vitamin D deficiency. Hence many companies are now in a process to develop newer ingredients with lesser side effects.
Selection of proper Sunscreen is of much importance along with the concentration of each sunscreen ingredients while using more than one active in formulation in order to obtain desire SPF value and final sun protection. Many companies are now also coming up with blend of UV filters which can be directly incorporated in the formulation and get the desire efficiency of the sunscreen product.
Considering all the aspects of sunscreen ingredient on human body in many countries it is regulated by Food and Drug regulatory authority and also sold as prescription product, specifically in developed countries.
All sunscreen active ingredients broadly classified as below based on methods by which they protect against sunlight.
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Organic chemical compounds that absorb ultraviolet light. (Such as Octylmethoxy Cinnamate, Avobenzone, and Octocrylene etc.)
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Inorganic particulates that reflect, scatter, and absorb UV light (such as titanium dioxide, zinc oxide, or a combination of both).
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Organic particulates that mostly absorb UV light like organic chemical compounds, but contain multiple chromophores that reflect and scatter a fraction of light like inorganic particulates.
Sunscreens provide protection from the two types of damaging ultraviolet (UV) rays: UVA and UVB. Both UVA and UVB rays.