Evaluation of functional stability of quercetin as a raw material and in different topical formulations by its antilipoperoxidative activity

Abstract

The present study evaluates the antioxidant activity of the flavonol quercetin, and its functional stability as a raw material and when added in formulations. The iron-chelating activity was determined using the bathophenanthroline assay, and the functional stability was evaluated with the antilipoperoxidative assay. Raw material presented concentrationdependent antilipoperoxidative and iron-chelating activities. The initial antilipoperoxidative activity of the raw material, cream and gel-cream were 63%, 78%, and 69%, respectively. There was no detectable loss of activity during 182 days (6 months) of storage at all tested temperatures (4°C, room temperature [RT], 37°C, and 45°C) for the raw material. Considering the method variability of 10%, activity loss greater than 10% for nonionic cream was detected after 126 days at 4°C (20.1%), decreasing thereafter to 22.2% after 182 days. At 45°C, the loss of activity started after 182 days (13.2%). For the anionic gel-cream, activity loss started after 84 days (28.4%, 45°C), decreasing after 182 days to 40.3% at 45°C. At 37°C, activity loss was detected after 182 days (12%). In conclusion, the results suggest that the activity of quercetin depends on iron chelation, and its possible usefulness as a topical antioxidant to prevent oxidative stress-induced skin damage depends on maintaining its antilipoperoxidative activity stored at RT, which avoids special storage conditions.

Quercetin in Lyotropic Liquid Crystalline Formulations: Physical, Chemical and Functional Stability

“…Functional stability guarantees the efficacy of a product with a specific function and has been proposed as a different approach to evaluate the stability of quercetin as an active pharmaceutical ingredient and also in different topical formulations (17,18).…”

Method validation and stability study of quercetin in topical emulsions

“…15 Quercetin is a promising compound to combat free radical diseases such as cancer and inflammatory conditions. Furthermore, its topical effectiveness to protect the skin from oxidative stress has been recently demonstrated, 6,13,16 which reinforces the importance of quality control of topical formulation containing quercetin. In this sense, this work demonstrates one of the most valuable tools in the pharmaceutical analysis of quality control, 11 which is a HPLC assay for the analysis of quercetin in topical formulations.…”

“…It provides information concerning to the shelf-life of pharmaceutical products and conditions for their storage. 13,18 Emulsions must be tested at widely varying temperatures in order to ensure that the product will remain stable throughout all possible conditions. For accelerated temperature testing, it is important to remember that temperature stability protocols depend on product category.…”

“…13 Samples were collected at pre-determined time intervals for pH, centrifugation, optical microscopic analyses and evaluation of quercetin concentration.…”

Elucidating Raw Material Variability—Importance of Surface Properties and Functionality in Pharmaceutical Powders

“…The production of pharmaceutical excipients uses a series of processing steps aimed at eliminating the natural variability of such materials. Despite such efforts, however, excipient variability is not uncommon; there are frequent reports of excipient variability in the pharmaceutical literature (12)(13)(14)(15)(16)(17)(18). In order to assure interchangeability between the different sources (manufacturers) of the same excipient or between different batches from the same source, the common practice in the industry is to perform a series of analytical tests, based on strict specifications for the particular raw material.…”