Intercalation compounds of ZnAl-hydrotalcite with the UV absorber 5-benzoyl-4-hydroxy-2-methoxy-benzenesulphonate acid (4BHF) have been prepared by ion exchange procedure and used to obtain sunscreen stabilization for new cosmetic formulations. Compounds having a sunscreen loading from 26% to 38% w/w have been obtained changing the pH of the equilibrating solution. In fact, taking advantage of the bi-protic nature of 4BHF, the mono-anions, the di-anions or a mixture of mono- and di-valent anions have been intercalated into the hydrotalcite. The compounds obtained have been firstly characterized by TG, XRPD, DSC, and SEM techniques, and then dispersed in a suitable waterproof silicon cream to obtain new sunscreen formulations. The in vitro 4BHF release from the formulation has been determined. Furthermore, the intercalation products and their formulations have been investigated by means UV–vis absorption spectroscopy in order to study the matrix influence on sunscreen sunlight protection effect and on their photostability. The 4BHF intercalation between ZnAl-hydrotalcite lamellae can be considered a good strategy to increase the sunscreen stability and to prepare solar cosmetic formulations always more efficacious and safe.
Sunscreen immobilization on ZnAl-hydrotalcite for new cosmetic formulations.
PERIOLI, Luana;NOCCHETTI, Morena;AMBROGI, Valeria;LATTERINI, Loredana;ROSSI, Carlo;
2008
Abstract
Intercalation compounds of ZnAl-hydrotalcite with the UV absorber 5-benzoyl-4-hydroxy-2-methoxy-benzenesulphonate acid (4BHF) have been prepared by ion exchange procedure and used to obtain sunscreen stabilization for new cosmetic formulations. Compounds having a sunscreen loading from 26% to 38% w/w have been obtained changing the pH of the equilibrating solution. In fact, taking advantage of the bi-protic nature of 4BHF, the mono-anions, the di-anions or a mixture of mono- and di-valent anions have been intercalated into the hydrotalcite. The compounds obtained have been firstly characterized by TG, XRPD, DSC, and SEM techniques, and then dispersed in a suitable waterproof silicon cream to obtain new sunscreen formulations. The in vitro 4BHF release from the formulation has been determined. Furthermore, the intercalation products and their formulations have been investigated by means UV–vis absorption spectroscopy in order to study the matrix influence on sunscreen sunlight protection effect and on their photostability. The 4BHF intercalation between ZnAl-hydrotalcite lamellae can be considered a good strategy to increase the sunscreen stability and to prepare solar cosmetic formulations always more efficacious and safe.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
