Organic ultraviolet UV filters are chemical compounds used in sunscreen lotions to protect the skin from harmful UV radiation. They work by absorbing, reflecting, or scattering the UV rays, preventing them from penetrating the skin and causing damage. There are several types of organic UV filters, and they can be classified based on their modes of action:1. UV Absorbers: These filters work by absorbing the UV radiation and converting it into a less harmful form of energy, such as heat. They contain molecules with specific chemical structures that allow them to absorb UV rays at different wavelengths. Examples of UV absorbers include: a. Benzophenones: These compounds absorb UVB radiation 280-320 nm and some UVA radiation 320-400 nm . Examples include oxybenzone and dioxybenzone. b. Cinnamates: These compounds primarily absorb UVB radiation. Examples include octinoxate and cinoxate. c. Salicylates: These compounds absorb UVB radiation and have a weaker absorption capacity compared to other UV absorbers. Examples include octisalate and homosalate. d. Avobenzone: This compound absorbs UVA radiation, particularly UVA1 340-400 nm , and provides broad-spectrum protection when combined with other UV filters.2. UV Reflectors: These filters work by reflecting or scattering the UV radiation, preventing it from reaching the skin. They contain particles that are larger than the wavelength of UV radiation, which allows them to effectively scatter the rays. Examples of UV reflectors include: a. Titanium dioxide: This compound reflects both UVA and UVB radiation and is often used in combination with other UV filters for broad-spectrum protection. b. Zinc oxide: This compound reflects both UVA and UVB radiation and provides broad-spectrum protection. It is often used in physical sunscreens and is considered to be less irritating to the skin compared to some chemical filters.3. UV Stabilizers: These filters help to stabilize and enhance the performance of other UV filters in the sunscreen formulation. They work by preventing the degradation of other UV filters when exposed to sunlight, ensuring that the sunscreen remains effective for a longer period. Examples of UV stabilizers include: a. Octocrylene: This compound absorbs UVB radiation and helps to stabilize avobenzone, preventing its degradation when exposed to sunlight. b. Tinosorb S and Tinosorb M: These compounds absorb both UVA and UVB radiation and help to stabilize other UV filters in the formulation.In summary, organic UV filters in sunscreen lotions protect the skin from harmful UV radiation through various modes of action, including absorption, reflection, and stabilization. By combining different types of filters, sunscreen formulations can provide broad-spectrum protection against both UVA and UVB radiation, reducing the risk of skin damage, premature aging, and skin cancer.