Formulation and Evaluation of Solid Dispersions of Furosemide in Sodium Starch Glycolate

Purpose: This investigation was carried out to determine if a solid dispersion of furosemide in sodium starch glycolate (SSG) would enhance the dissolution properties of the drug.
Methods: Solid dispersion of furosemide in SSG was prepared in ratios of 1:1 and 1 (furosemide):2 (SSG) by kneading method. In each case, the solid dispersion was characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) to ascertain if there were any physicochemical interactions between drug and carrier that could affect dissolution. Tablets containing the solid dispersion were formulated and their dissolution characteristics compared with commercial furosemide tablets. The dissolution studies were performed at 37 ± 0.5°C and 50 rpm in simulated gastric fluid (pH 1.2).
Results: FTIR spectroscopy, DSC, and XRD showed a change in crystal structure toward an amorphous form of furosemide. Dissolution data indicated that furosemide dissolution was enhanced. XRD, DSC, FTIR spectroscopy and dissolution studies indicated that the solid dispersion formulated in 1:2 ratio showed a 5.40-fold increase in dissolution and also exhibited superior dissolution characteristics to commercial furosemide tablets.
Conclusion: Solid dispersion technique can be used to improve the dissolution of furosemide.

Keywords
Solid dispersion, Furosemide, Sodium starch glycolate, Dissolution enhancement, physicochemical characterisation.