Catalog NumberHG-RHE-M018
CategoryRheology Modifiers
Acrylates/Beheneth-25 Methacrylate Copolymer as a Polymeric Emulsifier to Delay UV-Filter Recrystallization in Sunscreens
Sohn, Myriam, et al. Journal of Pharmaceutical Sciences 108.5 (2019): 1800-1807.
This study evaluated the performance of Acrylates/Beheneth-25 Methacrylate Copolymer (used at 2% w/w, referred to as polymeric 1) as an emulsifying polymer to slow the recrystallization of oversaturated, crystalline lipophilic UV filters and thereby preserve delivered photoprotection.
Experimental Design: The study compared 24 sunscreen formulations that differed only in emulsifier system-six oil-in-water (anionic, mixed anionic/non-ionic, mixed non-ionic/polymeric and two polymeric variants including Acrylates/Beheneth-25 Methacrylate Copolymer at 2% w/w), one water-in-oil, and one switch-oil-phase (SWOP) base-while keeping the oil phase (dibutyl adipate : dicaprylyl carbonate, 5:3), humectants and auxiliaries constant. Four crystalline, lipophilic UV filters (BEMT 2.5% w/w, EHT 3.0% w/w, DHHB 8.0% w/w and BMDBM 4.4% w/w) were loaded above their saturation in the emollient to promote recrystallization, and formulations were prepared by heating phases to 80 °C for emulsification then cooling to ambient temperature.
Key Finding: Microscopic evaluation of the recrystallization speed revealed significant differences between the emulsifying systems. The formulation stabilized with Acrylates/Beheneth-25 Methacrylate Copolymer demonstrated a pronounced ability to delay the recrystallization of UV filters. This stabilizing effect was particularly beneficial for the two UVA filters tested, which showed a notably slower crystal growth rate in the polymeric emulsion compared to other systems. Measured absorbance of formulations decreased after recrystallization, confirming that crystal growth negatively affects sunscreen performance.
Acrylates/Beheneth-25 Methacrylate Copolymer as a Structural Polymer in a High-Oil O/W Body Butter
Tafuro, Giovanni, et al. Cosmetics 11.2 (2024): 60.
This study evaluated the role of Acrylates/Beheneth-25 Methacrylate Copolymer (used alongside sodium polyacrylate) in supporting the semi-solid structure of a high-oil oil-in-water (O/W) body butter and assess performance when the synthetic texturizer PMMA is replaced by biodegradable, naturally derived alternatives.
Formulation: The formula is an O/W body butter with a large lipid phase composed of synthetic esters, triglycerides, natural waxes and fatty alcohols. The emulsifying system combines non-ionic and anionic surfactants. Synthetic polymers (sodium polyacrylate and the Acrylates/Beheneth-25 Methacrylate Copolymer) provide the semi-solid network that supports the high oil content. Four biodegradable powders - two organic (Z: zea mays starch + olive-oil glycerin + PVA; M: maltodextrin) and two inorganic (H: mica; S: mixture of aluminum silicate, titanium dioxide and silica) - were tested for replacing the PMMA texturizer (3% w/w).
Key Results:
· The Acrylates/Beheneth-25 Methacrylate Copolymer base effectively maintained the emulsion's core structure across all variants.
· Texture analysis revealed that the inorganic texturizers (S and H) significantly enhanced the mechanical properties of the emulsion, outperforming the organic alternatives. Their superior wettability was particularly beneficial in the high-oil-phase system.
· Rheological data confirmed that by adjusting the concentration of the inorganic texturizer S to 1.5% w/w, the reformulated product achieved viscosity and elasticity parameters most similar to the original PMMA-containing body butter.