Characterization of nimodipine amorphous nanopowder prepared by quenching cooling combined with wet milling and spray drying

Currently, reducing particle size or preparing drugs into amorphous forms are widely used methods to improve the solubility and dissolution rate of insoluble drugs. The purpose of this study was to prepare nimodipine amorphous nanopowder (NMD-NAP) using nimodipine (NMD) as a model drug to increase the solubility and dissolution rate of insoluble drugs by the combined effect of reducing the particle size and preparing the drug into an amorphous form. The NMD-NAP was successfully prepared by quenching cooling combined with wet milling and spray drying. The prepared NMD-NAP was shown to have good redispersibility by particle size analysis. The shapeof NMD-NAP was characterized by SEM and AFM, showing a spherical or spheroidal structure. The results of PLM, DSC, XRD, and FT-IR indicated that the drug existed in an amorphous form. The dissolution study showed that the dissolution rate of NMD in NMD-NAP was improved about 5 times that of pure NMD and 3 times that of nimodipine nanocrystalline (NMD-NC), indicating the combination of nano size and amorphous form produced a synergistic effect that could significantly increase the dissolution rate of NMD. Due to the significantly improved solubility and good industrial feasibility of the prepared NMD-NAP, the preparation of insoluble drugs into amorphous nanopowders is an effective method to improve the solubility of insoluble drugs and has good application prospects.