Sunscreen Enhancement of Octyl Methoxycinnamate Microcapsules by Using Two Biopolymers as Wall Materials

Abstract

Octyl methoxycinnamate (OMC) is widely used as a chemical sunscreen in sunscreen cosmetics. However, its direct contact with the skin would bring certain risks, such as skin photosensitive reaction. How to improve the effect of skin photodamage protection has become a current research hotspot. Encapsulating ultraviolet (UV) filters into microcapsules is an interesting method to increase the photostability of filters. In this study, sodium caseinate (SC) and arabic gum (GA) are chosen as wall materials to prepare synergistic sunscreen microcapsules by complex coacervation technology. A series of experiments are conducted to investigate the effects of pH, wall material concentration, and wall/core ratio on the formation of OMC microcapsules. The morphology, composition, and stability of OMC microcapsules are characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The OMC microcapsule is uniform in size distribution, smooth in surface morphology, and has good thermal stability. The results show that the ultraviolet absorption of the OMC microcapsules is better than that of the uncoated OMC for the ultraviolet-B (280–320 nm). Moreover, the OMC microcapsule released 40% in 12 h, while OMC released 65%, but the sun protection factor (SPF) of the OMC microcapsule sunscreen is 18.75% higher than that of OMC. This phenomenon may be attributed to the hydrophobic interaction between SC and OMC and the electrostatic interaction between SC and GA.

Enhanced Sunscreen Effects via Layer-By-Layer Self-Assembly of Chitosan/Sodium Alginate/Calcium Chloride/EHA

“…As shown in Figure 11 , the free EHA and sunscreen nanocapsules all have high absorbance between 280 and 320 nm, and the maximum absorption intensity of 2.11 was 311 nm, which suggested sunscreen nanocapsules had a better sunscreen effect than free EHA. The maximum absorbance of the sunscreen nanocapsules was larger than that of free EHA, indicating that the sunscreen effect of sunscreen nanocapsules was better than that of free EHA, which due to the sunscreen nanocapsules were not only had the UV absorption function of chemical sunscreen, but also had the effect of physical sunscreen on ultraviolet reflection [ 44 ]. In detail, firstly, the EHA encapsulated by nanocapsules still had a good effect in sunscreen, secondly, the sunscreen nanocapsules as a spherical particle with nano-size had different degrees of scattering and refraction to ultraviolet rays except absorbing ultraviolet rays, leading to higher absorbance, thirdly, due to the nano-size, the sunscreen nanocapsules could be arranged closely on the 3 m tape and the clearance between particles was small, which had a certain diffraction effect on ultraviolet light, leading to the light transmittance reduced and the absorbency improved.…”

Recent developments in sunscreens based on chromophore compounds and nanoparticles

“…18b). 54 Solvent displacement was used to manufacture biodegradable polymer nanocapsules (35) that contained the lipophilic sunscreen Parsol MCX (OMC) as the oil core. To look into the formulations' photoprotective potential, and OMC loading ability, with stabilizing agent effects (polysorbate 85, P-85, and poloxamer 188, P-188).…”

Design of Bombyx mori (B. mori) Silk Fibroin Microspheres for Developing Biosafe Sunscreen

“…Excessive ultraviolet (UV) radiation could damage our skin in daily life. Prolonged UV irradiation induces the generation of reactive oxygen species (ROS), leading to epidermis inflammation, keratin deposition, and premature aging of the skin, etc. − Moreover, UV is harmful to DNA by creating cyclobutene pyrimidine dimers (CPDs) during its replication, resulting in skin cancer. , Various sunscreens have been developed for resisting UV. − Inorganic sunscreens, including titanium dioxide (TiO 2 ) and zinc oxide (ZnO), as well as organic sunscreens, such as octyl methoxy cinnamate (OMC) and avobenzone, are strong UV absorbing agents. ,− However, the high UV-absorbing capacity of these sunscreens is often accompanied by the generation of free radicals. During the photoprotection, inorganic sunscreens yield additional ROS due to their intrinsic photocatalytic activities while organic sunscreens photodegrad into lethal free radicals. − Besides, these sunscreens can also penetrate the skin because of their nanosize, eventually triggering inflammations in the tissues or even influencing the circulatory system. ,, Hence, there is a great demand to develop sunscreens with high UV-resistance efficiency as well as credible biosafety.…”