Influence of sodium metabisulfite and glutathione on the stability of vitamin C in O/W emulsion and extemporaneous aqueous gel.
Vitamin C exerts several functions on skin as collagen synthesis, depigmentant and antioxidant activity. Vitamin C is unstable in the presence of oxygen, luminosity, humidity, high temperatures and heavy metals, which presents a significant challenge to the development of cosmetic formulations. Therefore, the utilization of an effective antioxidant system is required to maintain the vitamin C stability. The purpose of this research work was to develop prototypes of cosmetic formulations, as O/W emulsion and extemporaneous aqueous gel, containing vitamin C and to evaluate the influence of sodium metabisulfite (SMB) and glutathione (GLT), as antioxidants, on the stability of the active substance. A HPLC stability-indicating method was developed and validated for this study and stability assays were performed in 90 and 26 days and storage conditions were 5.0+/-0.5, 24+/-2 and 40.0+/-0.5 degrees C. The HPLC stability-indicating method showed linearity (r(2)>0.99), specificity, R.S.D.<1.22% and accuracy/recovery ranging from 95.46 to 101.54%. Preparations with SMB or GLT and the antioxidant-free presented results statistically distinct, demonstrating the necessity of the antioxidant system addition. O/W emulsions with SMB or GLT retained the vitamin C content >90.38% stored at 5.0+/-0.5 and 24+/-2 degrees C. For the aqueous gel with SMB or GLT, the active substance concentration was maintained >94.03%. Considering the vitamin C stability, the SMB and the GLT showed to be statistically adequate, as antioxidants, for the cosmetic formulations.
Maia
Adriana M
AM
Laboratory of Cosmetology, Department of Pharmacy, School of Pharmaceutical Sciences, University of São Paulo, 580 Prof. Lineu Prestes Av., bl. 13, Conjunto das Químicas, Cidade Universitária, 05508-900 São Paulo, SP, Brazil.
Baby
André Rolim
AR
Pinto
Claudinéia A S O
CA
Yasaka
Wilson J
WJ
Suenaga
Eunice
E
Kaneko
Telma M
TM
Velasco
Maria Valéria Robles
MV
D000975:Antioxidants / Q000737:chemistry*; D001205:Ascorbic Acid / Q000032:analysis / Q000737:chemistry*; D004355:Drug Stability; D004655:Emulsions; D005782:Gels; D005978:Glutathione / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D013447:Sulfites / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D000975:Antioxidants; D004655:Emulsions; D005782:Gels; D009821:Oils; D013447:Sulfites; D014867:Water; C005200:sodium metabisulfite; D005978:Glutathione; D001205:Ascorbic Acid