Oxidative photodamage refers to the damage caused by the absorption of ultraviolet UV radiation and the subsequent generation of reactive oxygen species ROS such as free radicals and singlet oxygen. These reactive species can cause oxidative stress, leading to the degradation of organic molecules, including common sunscreen agents like oxybenzone and avobenzone.Oxybenzone and avobenzone are organic UV filters that primarily absorb UV radiation in the UVA and UVB range, respectively. They protect the skin by converting the absorbed UV energy into less harmful forms, such as heat. However, upon exposure to UV radiation, these sunscreen agents can undergo structural changes, leading to a decrease in their UV absorption properties.For oxybenzone, photodegradation can lead to the formation of various photoproducts, such as benzophenone and other derivatives. These photoproducts have reduced UV absorption capabilities compared to the parent compound, resulting in decreased sunscreen efficacy. Additionally, some of these photoproducts can generate ROS, further contributing to oxidative stress and potential skin damage.Similarly, avobenzone is also susceptible to photodegradation upon exposure to UV radiation. The primary photoproducts of avobenzone include various isomers and ring-opened forms, which have lower UV absorption properties than the parent compound. This photodegradation can lead to a reduction in the sunscreen's ability to protect against UVA radiation.To mitigate the effects of oxidative photodamage on the UV absorption properties of these sunscreen agents, several strategies can be employed:1. Formulation with photostabilizers: Incorporating photostabilizers, such as octocrylene or ecamsule, can help protect oxybenzone and avobenzone from photodegradation, thereby maintaining their UV absorption properties.2. Use of antioxidants: Adding antioxidants, such as vitamin E or green tea extract, to sunscreen formulations can help neutralize ROS generated during UV exposure, reducing oxidative stress and the potential for photodegradation.3. Combination with inorganic UV filters: Combining organic UV filters like oxybenzone and avobenzone with inorganic filters, such as zinc oxide or titanium dioxide, can provide broad-spectrum protection and reduce the overall burden on the organic filters, potentially increasing their stability.In conclusion, oxidative photodamage can negatively impact the UV absorption properties of common sunscreen agents like oxybenzone and avobenzone. However, by employing strategies such as using photostabilizers, antioxidants, and combining with inorganic UV filters, the stability and efficacy of these sunscreen agents can be improved.