Solubility enhancement of nimodipine through preparation of Soluplus® dispersions

ABSTRACT

The present work aims to enhance the water solubility of nimodipine, a hydrophobic drug, using a solid dispersion(SD) technique. Soluplus® as a novel hydrophilic polymeric carrier was used. Nimodipine-Soluplus® SDs (110) wereprepared by impregnation technique using supercritical fluid technology (SCF) and compared with the ones whichwere prepared by conventional hot-melt (HM) method. The solubility and the in vitro release study of the raw drug,solid dispersions, and the corresponding physical mixtures were characterized and compared. The prepared SD bySCF technology showed 77-fold increase in nimodipine solubility, in comparison to 48-fold increase when preparedby HM and 7.7-fold when physically mixed. Moreover, they showed the highest percentage of nimodipine cumulativerelease within the studied period. The results were confirmed the amorphous transfer of the drug into the polymermatrix which was assured by the powder X-ray diffraction and the thermal analysis. In addition to the hydrogen bondformation between nimodipine and Soluplus®, which was evident in the FTIR spectra; A weakening of peak related tonimodipine N–H stretching and C=O of the ester group. Nimodipine solid dispersion with Soluplus® using the SCFtechnology might represent a promising formulation for nimodipine to enhance its oral bioavailability: