DEVELOPMENT OF FELODIPINE LOADED SMEDDS FOR IMPROVING ORAL BIOAVAILABILITY

Felodipine is a poorly water soluble drug having 15% oral bioavailability. In the present study Self micro emulsifying drug delivery system of felodipine was developed to improve its solubility and bioavailability. SMEDDS were prepared by phase titration method and ternary phase diagram was constructed using Chemix software. Based on solubility of drug in the excipients, capmul MCM, oleic acid, Tween 80 and PEG 400 were selected as oil, surfactant and co-surfactant respectively. Liquid SMEDDS were characterized for self-micro emulsification time, droplet size, poly dispersity index, zeta potential, drug release, ex-vivo permeation. The optimized liquid SMEDDS formulation F16 contained capmul MCM (35%), tween 80 (55%), PEG 400 (10%). Formulation F16 has size of 13.66 nm, zeta potential-25.7 mV, drug release 78% in 8 h. The optimized liquid SMEDDS were converted into solid SMEDDS by adsorbing on to neusilin. The drug release was studied in 0.1N HCl and phosphate buffers pH 6.8 using dissolution apparatus II. The dissolution from liquid SMEDDS and solid SMEDDS was significantly high (P<0.0001) compared to drug suspension. The drug permeation was studied by normal sac method. SMEDDS formulation showed significantly high permeation (P<0.007) compared to drug suspension. Single pass intestinal perfusion study was conducted in rats and the effective permeability coefficient (P_eff) of felodipine loaded SMEDDS (16.3 ± 0.86 × 10^-3 ml/min/cm²) were significantly high (P<0.05) compared with drug suspension (7.5 ± 0.87 × 10^-3 ml/min/cm²). The results of the study confirmed that SMEDDS formulation of felodipine could improve the oral bioavailability significantly.