title: Quercetin in lyotropic liquid crystalline formulations: physical, chemical and functional stability.
abstract: The purpose of this study was to develop a lyotropic liquid crystalline formulation using the emulsifier vitamin E TPGS and evaluate its behavior after incorporation of a flavonoid, quercetin. The physical (macro and microscopic), chemical (determination of quercetin content by the HPLC method) and functional (determination of quercetin antioxidant activity by DPPH(*) assay) stability of the lamellar liquid crystalline formulation containing flavonoid was evaluated when stored at 4 +/- 2 degrees C; 30 +/- 2 degrees C/70 +/- 5% RH (relative humidity) and 40 +/- 2 degrees C/70 +/- 5% RH during 12 months. The lamellar liquid crystalline structure of the formulation was maintained during the experiment, however chemical and functional stability results showed a great influence of the storage period in all conditions tested. A significant decrease in quercetin content (approximately 40%) was detected during the first month of storage and a similar significant loss in antioxidant activity was detected after 6 months. The remaining flavonoid content was unchanged during the final 6 months of the experimental period. The results suggest possible interactions between quercetin and the liquid crystalline formulation, which could inhibit or reduce the quercetin activity incorporated in the system. In conclusion, the present study demonstrated that incorporation of quercetin (1%) did not affect the liquid crystalline structure composed of vitamin E TPGS/IPM/PG-H2O (1:1) at 63.75/21.25/15 (w/w/w). Nevertheless, of the total quercetin incorporated in the system only 60% was free to act as an antioxidant.
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/n, 14040-903 Ribeirão Preto, São Paulo, Brazil.
authors.forename: Fabiana T M C
authors.initials: FT
authors.lastname: Vicentini
authors.forename: Rúbia
authors.initials: R
authors.lastname: Casagrande
authors.forename: Waldiceu A
authors.initials: WA
authors.lastname: Verri
authors.forename: Sandra R
authors.initials: SR
authors.lastname: Georgetti
authors.forename: M Vitória L B
authors.initials: MV
authors.lastname: Bentley
authors.forename: Maria J V
authors.initials: MJ
authors.lastname: Fonseca
mesh_terms: D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D004304:Dosage Forms; D004339:Drug Compounding; D004355:Drug Stability; D045703:Emulsifying Agents / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry*; D006813:Humidity; D050866:Liquid Crystals; D009226:Myristates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D019946:Propylene Glycol / Q000737:chemistry; D011794:Quercetin / Q000737:chemistry*; D013678:Technology, Pharmaceutical / Q000379:methods; D013696:Temperature; D013997:Time Factors; D014810:Vitamin E / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D004304:Dosage Forms; D045703:Emulsifying Agents; D016166:Free Radical Scavengers; D009226:Myristates; C008205:isopropyl myristate; D014810:Vitamin E; D011092:Polyethylene Glycols; D019946:Propylene Glycol; D011794:Quercetin; C014225:tocophersolan