Formulation Development and Comparative Pharmacokinetic Evaluation of Felodipine Nanoemulsions in SD Rats

The present study involves the formulation and evaluation of o/w nanoemulsions with two simple edible oils in micro-liter quantities, avoiding large quantities of surfactants and co-surfactants. The nanoemulsions were prepared by high energy emulsification technique. The process optimization was based on the particle size, size distribution and entrapment efficiency in relation with the quantity of oil and concentration of surfactant. The percent drug content was determined by HPLC with UV detector. The particle size, polydispersity index (PDI), and zeta potential of nanoemulsions were determined by using particle sizer. Stability studies at 4°C for two months, centrifugation and freeze-thaw cycling were carried out.  Pharmacokinetic studies of nanoemulsion and marketed dosage form were performed in male SD rats and blood plasma samples were analyzed by LC-MS/MS. The particle size, polydispersity index (PDI), and zeta potential of nanoemulsions were found to be in the range of 26.8±0.72 to 154.6±11.4 nm, 0.09±0.01 to 0.28±0.06 and 0.07±0.01 to -28±0.65 mv respectively. Transmission electron microscopy (TEM) and stability studies revealed the physical stability of the nanoemulsions. The percent drug content was found to be in the range of 73.74±3.79 to 101.16±1.35. The oral bio-availability was significantly increased in nanoemulsion compared with the marketed dosage form. These results showed a successful incorporation of felodipine into nanoemulsion with high drug loading efficiency and good stability. Key words: Sesame oil, olive oil, felodipine, sonication, Oral bioavailability.