Trolox (6-hydroxy-2,5,7,8-tetramethylchroman- 2-carboxylic acid), a derivative of vitamin E, can undergo photolysis upon UV irradiation. In the present study the photodegradation kinetics of Trolox were thus investigated in different systems in the absence and in the presence of titanium dioxide, a physical sunscreen present in several cosmetic products, that can act as photocatalyst. In all the considered media Trolox degraded under UVB light following pseudo-zero order kinetics, probably by a mechanism of photooxidation. The rate of Trolox photodegradation was lower in O/W emulsions than in aqueous solution and in gel; furthermore it was significantly influenced by the presence of TiO2. Aiming to increase Trolox stability, it was complexed with hydroxypropyl-b-cyclodextrin: the inclusion complex was characterized by phase solubility studies, spectrophotometry and differential scanning calorimetry. The irradiation experiments indicated that complexation with hydroxypropyl-b-cyclodextrin was effective in reducing the photodegradation rate of Trolox. Moreover the host molecule favored the uptake of Trolox into the porcine skin, as shown by in vitro permeation studies. Nevertheless the assay of peroxidation, based on the reaction of malondialdehyde with thiobarbituric acid, indicated that the antioxidant activity of Trolox was maintained even after inclusion in cyclodextrin.

Influence of hydroxypropyl-beta-cyclodextrin on the photostability and antiradical activity of Trolox

CARLOTTI, Maria Eugenia;SAPINO, Simona;UGAZIO, Elena;TROTTA, Francesco;VIONE, Davide Vittorio;CHIRIO, Daniela;CAVALLI, Roberta
2008

Abstract

Trolox (6-hydroxy-2,5,7,8-tetramethylchroman- 2-carboxylic acid), a derivative of vitamin E, can undergo photolysis upon UV irradiation. In the present study the photodegradation kinetics of Trolox were thus investigated in different systems in the absence and in the presence of titanium dioxide, a physical sunscreen present in several cosmetic products, that can act as photocatalyst. In all the considered media Trolox degraded under UVB light following pseudo-zero order kinetics, probably by a mechanism of photooxidation. The rate of Trolox photodegradation was lower in O/W emulsions than in aqueous solution and in gel; furthermore it was significantly influenced by the presence of TiO2. Aiming to increase Trolox stability, it was complexed with hydroxypropyl-b-cyclodextrin: the inclusion complex was characterized by phase solubility studies, spectrophotometry and differential scanning calorimetry. The irradiation experiments indicated that complexation with hydroxypropyl-b-cyclodextrin was effective in reducing the photodegradation rate of Trolox. Moreover the host molecule favored the uptake of Trolox into the porcine skin, as shown by in vitro permeation studies. Nevertheless the assay of peroxidation, based on the reaction of malondialdehyde with thiobarbituric acid, indicated that the antioxidant activity of Trolox was maintained even after inclusion in cyclodextrin.
JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY
61
279
287
Hydroxypropyl-b-cyclodextrin; Lipoperoxidation; UVB-induced degradation; Skin uptake; TiO2; Trolox
Carlotti, M.E.; Sapino, S.; Marino, S.; Ugazio, E.; Trotta, F.; Vione, D.; Chirio, D.; Cavalli, R.
File in questo prodotto:
File Dimensione Formato  
JIPMC_2008_OA_4aperto.pdf

embargo fino al 31/03/2009

Descrizione: Articolo principale
Tipo di file: POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione 680.8 kB
Formato Adobe PDF
680.8 kB Adobe PDF Visualizza/Apri
JIPMC_2008_61_Trolox.pdf

non disponibili

Descrizione: Articolo principale
Tipo di file: PDF EDITORIALE
Dimensione 315.47 kB
Formato Adobe PDF
315.47 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2318/52570
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 7
social impact