Dissolution enhancement of felodipine by amorphous nanodispersions using an amphiphilic polymer: insight into the role of drug–polymer interactions on drug dissolution

Felodipine, a poorly soluble drug, is widely used in the treatment of angina pectoris and hypertension.This study aimed at the preparation of amorphous solid dispersion (SD) of felodipine using an amphiphilic polymer, soluplus, for the potential enhancement in solubility of the drug.Solid dispersions with varying proportions of drug and soluplus were prepared and the rate and extent of dissolution from SDs was compared with that of the pure drug. FT-IR and (1)H NMR spectroscopic analysis were carried out to examine the formation mechanism of SDs. Various techniques were used for solid state characterization of designed SDs.Formation of amorphous solid dispersions with particle size in nanometer range indicated suitability of polymer and method used in the preparation. FT-IR and (1)H NMR spectroscopy revealed that soluplus was involved in strong hydrogen bonding with felodipine molecules which resulted in the conversion of crystalline felodipine into amorphous form. Solid dispersion with 1:10 drug/polymer ratio showed more than 90% drug dissolution in 30 min whereas pure felodipine showed less than 19% drug dissolution in 1 h.Amorphous SDs of felodipine were prepared using soluplus resulting in substantial enhancement in the rate and extent of dissolution of felodipine.