New Hybrid Organic/Inorganic Polysilsesquioxane–Silica Particles as Sunscreens

Abstract

Effectiveness of organic sunscreens is limited by phototoxicity and degradation. Both of which can be significantly reduced by encapsulation in hollow particles or covalent incorporation into the solid structure of particles, but direct comparisons of the two methods have not been reported. In this study, physical encapsulation and covalent incorporation of sunscreens were compared with 1 mol % salicylate and curcumeroid sunscreens. 2-Ethylhexyl salicylate was physically encapsulated in hollow silica nanoparticles prepared by oil-in-water (O/W) microemulsion polymerizations (E-Sal). Some of these particles were coated with an additional shell or cap of silica to reduce leaking of sunscreen (cap-E-Sal). Covalent incorporation involved co-polymerizing tetraethoxysilane (TEOS) with 0.2 mol % of new salicylate and curcuminoid sunscreen monomers with triethoxsilyl groups. Particles were prepared with the salicylate attached to the silica matrix through single silsesquioxane groups (pendant; P-Sal) and two silsesquioxane groups (bridged; B-Sal). Particles based on a new curcuminoid-bridged monomer were also prepared (B-Curc). Sunscreen leaching, photodegradation, and sunscreen performance were determined for the E-Sal, cap-E-Sal, P-Sal, B-Sal, and B-Curc particles. Covalent attachment, particularly with bridged sunscreen monomers, reduced leaching and photodegradation over physical encapsulation, even with capping.

Size and Optically Tunable Ethyl Cellulose Nanoparticles as Carriers for Organic UV Filters

“…The incorporation of individual organic UV filters into nanoparticles has been demonstrated with nanoparticles designed from materials such as: silica,, solid‐lipid nanoparticles, poly‐lactide particles,, gelatin, cyclodextrins, and ethyl cellulose (EC). Nanoparticles from EC, in particular, are very appealing as carriers for organic UV filters because: i) they are biobased and biocompatible, ii) the particles can be prepared in a simple precipitation process using acceptable solvents, and iii) they are suitable for use in various solvent systems thus multiple sunscreen formulation types i. e. emulsion, oil based and even formulations containing ethanol – EC is soluble only in pure ethanol and EC nanoparticles are perfectly stable in 25% v/v ethanol .…”

A Review of the Structure, Preparation, and Application of NLCs, PNPs, and PLNs

“…When the high-pressure homogenization method is used to prepare NLCs [37,38,39,40,41,42,43,44,45,46,47,48,49], the encapsulation efficiency of coenzyme Q 10 NLC is the highest. El-Salamouni et al [38] employed a modified high-shear homogenization method to prepare NLCs using glyceryl monostearate (GMS) as the solid lipid, castor oil as the liquid lipid, and Poloxamer188 as the surface active agent.…”

Lanthanide(III)‐Based Multicolor Luminescent Hybrid Gel for Amine Sensing

“…TMC-Si was synthesized according to al iterature method, [6] as shown in Scheme 1a.As olution of 1,3,5-benzenetricarbonyl trichloride (0.265 g, 1mmol) in benzene (3 mL) was added dropwise at 0 8Cu nder an itrogen atmosphere to as olution of APTES (0.73 mL, 3.1 mmol) and Et 3 N( 0.5 mL, 3.4 mmol) in benzene (7 mL), and the reaction mixture was stirred for 48 ha tr oom temperature, resulting in white precipitate (triethylammonium chloride), which was filtered off and the solvent was removed in vacuo. The clear, light-yellow oil was purified by running it through as ilica plug (ethyl acetate/dichloromethane = 2.5:1) and then drying the product in vacuo to obtain TMC-Si as aw hite solid.…”