Development and Characterisation of a Self-Emulsifying Drug Delivery System for Furosemide: Enhancing Drug Release and Gastrointestinal Permeability

Introduction: This study investigated the use of a self-microemulsifying drug delivery system to enhance the solubility and intestinal permeability of furosemide, a poorly soluble and poorly permeable drug with limited oral bioavailability. Methods: Formulations were developed using selected surfactants and oils, guided by pseudo-ternary phase diagrams. Dispersions were characterised for droplet size, electrokinetic potential, and drug release. Permeability was assessed ex vivo using ovine intestinal tissue in diffusion chambers. Results: The optimised formulation (sesame oil 10%, Tween 80 45%, polyethylene glycol 400 45%) formed droplets with a mean size of 0.78 μm, a size distribution span of 0.320, and an elec-trokinetic potential of -23.5 ± 3.84 mV, indicating good physical stability. At pH 1.2, the formula-tion exhibited significantly faster drug release, with a mean drug release time of 8.16 ± 0.36 minutes, compared to 28.76 ± 1.33 minutes for the commercial tablet. Ex vivo, the cumulative transport of furosemide across duodenal tissue was 0.981 ± 0.42% for the formulation, compared to 0.434 ± 0.17% for the tablet. The apparent permeability of furosemide in the formulation was more than twofold higher (7.09 x 10-7 cm/s vs. 3.06 x 10-7 cm/s) than the commercial tablet. Discussion: Smaller and uniformly distributed droplets enhanced drug release and intestinal transport. The improved solubility and permeability of the formulation indicate enhanced poten-tial for oral absorption. Conclusion: The self-microemulsifying system significantly improved furosemide’s solubility and intestinal permeability. Further in vivo studies are required to confirm improved oral bioa-vailability.