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

Abstract

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°C; 30±2°C/70± 5% RH (relative humidity) and 40±2°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-H 2 O (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.

Liquid crystalline systems containing Vitamin E TPGS for the controlled transdermal nicotine delivery

“…The association of Vitamin E TPGS, IPM and PG-water in the ratio 1:1 and 3:1 has been previously demonstrated (Vicentini et al, 2008). Polarized light microcopy analysis is shown in Figure 3.…”

“…Liquid crystalline phases were prepared as previously described by Vicentini et al (2008). To obtain the systems, mixtures of surfactant (Vitamin E TPGS) and oil (IPM) were prepared in different ratios (3:1, 1:1 and 1:3 (w/w)), which were diluted with a mixture of water and PG following the same ratio.…”

Formulation and in vitro release evaluation of newly synthesized palm kernel oil esters-based nanoemulsion delivery system for 30% ethanolic dried extract derived from local Phyllanthus urinaria for skin antiaging

“…[2][3][4] Topically applied antioxidants can directly enrich the natural antioxidant defense system and prevent/reduce oxidative damage to the skin. 7 Phyllanthus urinaria is a herbal plant belonging to the genus Phyllanthus, family Euphorbiaceae. The genus Phyllanthus is widely distributed in tropical and subtropical countries, including Malaysia, Indonesia, China, Southern India, and South America.…”

Novel lecithin-integrated liquid crystalline nanogels for enhanced cutaneous targeting of terconazole: development, in vitro and in vivo studies

“…It was reported that drug loading might influence the microstructure of liquid crystalline systems via interaction with curved bicontinuous lipid bilayer of liquid crystalline phase, by making the microstructure became unstable and thus resulting in a phase transformation. 60 However, the rheological behavior of Tr-loaded LCG revealed that Tr did not affect the microstructure of LCG significantly.…”

“…The anisotropic nature of liquid crystalline system was confirmed under PLM where it showed birefringence due to its molecular organization 39 as shown in Figure 3. As there are some parameters such as drug loading and the alteration of the system components proportions could affect the packing parameter of lecithin, thus affecting the prepared liquid crystalline phase, 60,63 whether drug loading and water capacity would affect the microstructure formed or not was investigated. It was observed that the structure features of the liquid crystals of LCG was not influenced by the incorporation of Tr into the system, but it was mainly affected by water content as depicted in Figure 4.…”