Planta Med 2007; 73 - P_263
DOI: 10.1055/s-2007-987044

Self-microemulsifying drug delivery systems as nanosystems for bioavailability enhancement of taxifolin in vitro

M Karlina 1, O Pozharitskaya 1, A Shikov 1
  • 1St-Petersburg Institute of Pharmacy, 27–424 Partizanskaya str, 195248, St.-Petersburg, Russia

Taxifolin, allocated from wood of larch, has a wide spectrum of biological activity, showing antioxidative, capillaroprotective, anti-inflammatory and antithrombotic effects [1,2]. Taxifolin is a poorly water soluble compound and has low bioavailability. There is an actual development of new drug forms on the basis of taxifolin. Self-microemulsifying drug delivery systems (SMEDDS) are perspective drug delivery systems for oral, nasal and transdermal applications. They represent thermodynamically stable systems with high bioavailability of the compounds.

The purpose of the present work was to prepare SMEDDS of taxifolin and to study the release rate of taxifolin in vitro.

A water-in-oil nanoemulsion containing 2% taxifolin, surfactant (Tween 80) and cosurfactant (propylene glycol), oil phase (Labrafil® M 1944 CS) and water was prepared. In vitro release was investigated by the USP 28 paddle over disc method at 100 rpm (temperature 32±1°C, dissolution medium water) at modeling of transdermal application and by using the USP 28 paddle method at 100 rpm (temperature 37±1°C, dissolution medium 1-octanol and water [3]) at modeling of oral application. Concentrations of taxifolin were analyzed by RP-HPLC.

It was shown, that release of taxifolin from nanoemulsion is described by the equation of first order kinetics, constants of rate release for modeling of transdermal and oral application were 0,9306 and 0,8479h-1, accordingly. Taxifolin release from SMEDDS was about 95% in 2 and 3h in models of transdermal and oral application, accordingly. Particle size in the nanoemulsion was evaluated upon dilution with aqueous media as described by [4]. It was concluded that bioavailability of taxifolin was enhanced greatly by SMEDDS. Alternative mechanisms, such as improved lymphatic transport pathway, other than improved release may contribute to enhancement of bioavailability of taxifolin.

References: [1] Middleton E. et al. (2000) Pharmacol. Rev. 52: 673–751. [2] Silva M.M. et al. (2002) Free Radical Res. 36: 1219–1227. [3] Karlina M. et al. (2006) Voprosy Biol. Med. Pharm. Chem. 9: 42–46. [4] Ghosh P.K. et al. (2006) AAPS Pharm Sci Tech, 7: art. 77