Influence of sodium metabisulfite and glutathione on the stability of vitamin C in O/W emulsion and extemporaneous aqueous gel

Accelerated chemical stability data of O/W fluid emulsions containing the extract of Trichilia catigua Adr. Juss (and) Ptychopetalum olacoides Bentham

“…The pH values of FE and FEL resulted in apparent variations of higher magnitude at 40.0 ± 0.5 o C with reduction of 13.8 and 19.7%, respectively. At high temperatures, alterations were expected for this physicochemical parameter since the temperature elevation possess direct influence on the stability of cosmetic and pharmaceutical dosage forms, as well, the active substances (Maia et al, 2006). Both formulations presented tendency to reduce the pH value at high temperature storage condition, probably, due to the deterioration of the components of the fluid emulsions and the active substances from the extract of Trichilia catigua FE samples presented reduction of the active substance of 3.36% for the room temperature condition and 0.68%, for the low temperature, after the 90 th day of the stability assay.…”

“…The UV-spectrophotometric method at 361.0 nm was previously validated (Rolim et al, 2005;Baby et al, 2006) for linearity, specificity, precision, accuracy, recovery, limit of detection (LOD) and limit of quantification (LOQ) (ICH Q2B, 1996;Feinberg, Raguènès, 1999;Analytical Procedures and Methods Validation, 2000;United States Pharmacopeia, 2004;Ramos et al, 2005;KedorHackmann et al, 2006). As solvent and blank, the mixture of ethanol 95.0% and acetic acid 0.02 M (99:1) was used.…”

Development and optimization of chemically stable lipid microspheres containing flunarizine

“…Particularly for F 8 , which involving the advanced antioxidant system for FZ, embodied a superior chemical stability to all the other LMs. Additionally, F 7 was a little bit stabile to F 6 , which can be properly explained by various ways to antioxidation between L-cysteine 20,21 and Na 2 SO 3 22 . Therefore, through the course of the higher incubation of 60 ± 2°C 10 days, F 8 seemed to be the optimal formulation for improving the chemical stability of FZ-LMs.…”

“…L-Cysteine was thought to act not only as a free radical scavenger by donating a hydrogen from its thiol group 20 but could also interact with lipid-derived hydroperoxides at the interface of the LMs 21 . Hydrosoluble Na 2 SO 3 , because of its reducible singlet oxygen, was usually added to formulations as an antioxidant 22 , which could effectively maintain the chemical stability of FZ in the aqueous phase and the dynamic equilibrium in the different phases of FZ-LMs. Hydrosoluble EDTA, a transition metal chelator, has been reported to dramatically retard lipid oxidation in oil-in-water LMs by removing iron from the droplet surface 23 , and it can also prevent interaction with peroxides 24 but only as far as iron is concerned.…”

Formulation and stability of ascorbic acid in topical preparations

“…[7] The minimal daily requirement for ascorbic acid in healthy adults is 40 to 60 mg. [8,9] Ascorbic acid is a water-soluble vitamin and is extensively used as such or in the form of a derivative such as sodium ascorbate and ascorbyl palmitate as an ingredient of anti-aging cosmetic products. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] It exerts several functions on the skin such as collagen synthesis, depigmentation and antioxidant activity. [15,29] As an antioxidant, it protects the skin by neutralizing reactive oxygen species (ROS) generated on exposure to sunlight.…”