Effect of high-pressure homogenization on formulation of TPGS loaded nanoemulsion of rutin – pharmacodynamic and antioxidant studies

Abstract

Polyphenolic bioflavonoid, Rutin possesses wide range of pharmacological activities. However, it shows poor bioavailability when administered orally. The aim of this study was to formulate and compare the potential of nanoemulsions for the solubility enhancement of rutin (RU) by using different techniques. RU-loaded nanoemulsions were prepared by spontaneous emulsification method and high-pressure homogenization (HPH) technique using sefsol 218 and tocopheryl polyethylene glycol 1000 succinate (TPGS) (1:1), solutol HS15 andtranscutol P as oil phase, surfactant and co-surfactant, respectively. The prepared formulations were compared for various parameters like droplet size, percentage transmittance, zeta potential, viscosity, refractive index and in vitro release. The HPH nanoemulsions showed smaller droplet size and increased in vitro release when compared to nanoemulsions prepared by spontaneous emulsification method. The optimized formulation showed spherical globules with average globule diameter of 18 nm and zeta potential of −41 mV. Cumulative percentage drug released obtained for RU, PF6 (spontaneous emulsification formulation F6) and HF6 (HPH formulation F6) were 41.5 ± 0.04%, 49.5 ± 0.06% and 94.8 ± 0.03%, respectively, after 6 h. The permeability of RU from HF6 was found to be ≈4.6 times higher than RU suspension during ex vivo everted gut sac studies. Antioxidant activity was determined by using DPPH assay and reducing power assay method. Results showed a high scavenging efficiency toward DPPH radicals by HF6. Anti-inflammatory effect of RU as determined by carrageenan-induced rat paw edema method was found to be higher (75.2 ± 4.8%) when compared to RU suspension (46.56 ± 3.5%). It can be inferred that TPGS-loaded nanoemulsion of RU serve as an effective tool in increasing solubility and permeability of RU.