Preparation and Characterization of Furosemide Solid Dispersion with Enhanced Solubility and Bioavailability

Furosemide (FMD), as a potent circulating diuretic, is commonly used for the treatment of hypertension and edema arising from cardiac, renal, and hepatic failure. However, the low solubility of furosemide restricts its dissolution and bioavailability. In this study, Polyvinylpyrrolidone K30 (PVP-K30), mesoporous (Syloid 244FP, Syloid XDP 3050), and non-mesoporous (Aeroperl 300, Aerosil 200) silica were chosen as combined carrier to develop novel amorphous solid dispersions of furosemide, and then its dissolution and bioavailability were evaluated. Characterization study included XRD, DSC, TGA, SEM, FT-IR, and molecular docking. We found that FMD:PVP-K30:244FP achieved its best performance in terms of dissolution at the ratio of 1:1:1 when PVP-K30 and mesoporous silica Syloid 244FP (244FP) were chosen as combined carrier. SEM, DSC, and XRD studies indicated that furosemide existed in an amorphous form in the solid dispersion. FT-IR and molecular docking analysis showed that there might be an intermolecular interaction between FMD and the carrier. Moreover, the in vivo pharmacokinetics study revealed that the bioavailability of solid dispersion in rats had significant improvement. In particular, Cmax and AUClast were greatly increased by 2.69- and 2.08-fold in the solid dispersion (FMD-PVP-K30-244FP) group, respectively, and the relative bioavailability was 208.00%. In conclusion, the solid dispersion (FMD-PVP-K30-244FP) can significantly improve the solubility and oral bioavailability of furosemide. Mesoporous silica can be used as an excellent carrier material for furosemide, which can provide new ideas and methods for improving the stability of solid dispersion and further improving the dissolution of insoluble drugs.