Furosemide – Soluplus® Solid Dispersion: Development and Characterization

Background: Recent patents reveal that Soluplus® has proved to be a promising excipient that modulates dissolution characteristics of many active pharmaceutical ingredients (WO2016161995A1, WO2016169534A1 and WO2016165676A1). Objective: Current article investigates stable solid solution of furosemide with Soluplus® to enhance the dissolution properties of the drug. Method: Drug to carrier ratios to prepare solid dispersion were selected based on the phase solubility study. Solid dispersions of furosemide with Soluplus® were prepared by solvent evaporation and fusion methods. Physicochemical parameters were characterized using Fourier transform infra-red spectrophotometer, thermo- gravimetric analyzer, differential thermal analyzer, and scanning electron microscopy. Drug release from the formulations was compared using USP type II (paddle type) dissolution apparatus containing 900 mL of phosphate buffer (pH - 6.8) maintained at 37±0.5°C at a paddle rotation speed of 50rpm. Results: Fourier transform infra-red spectroscopy confirmed absence of any chemical interaction while thermo-gravimetry and differential thermal analysis showed evidences of formation of a solid solution of furosemide. No furosemide crystals were observed under scanning electron microscope in case of solid dispersion. Dissolution data indicated that furosemide dissolution was enhanced to a great extent and drug to carrier ratio of 1:10 was found to be most suitable. Conclusion: Solid dispersions prepared by fusion method exhibited faster drug release compared to those prepared by solvent evaporation.