Nimodipine (NM) tablets with high dissolution containing NM solid dispersions prepared by hot-melt extrusion

Using a mixture of Eudragit® EPO and polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA) (Kollidon VA64) as carriers, a nimodipine solid dispersion (NM-SD) was prepared by hot-melt extrusion (HME) to achieve high dissolution. The dissolution profiles in 900 mL 0.1 mol/L HCl showed that the drug release of NM-SD reached 90% in 1 h. Powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) were used to characterize the state of NM. The results obtained showed that NM was in an amorphous form in the solid dispersion (SD). NM-SD tablets (NM-T-SD) were compressed by wet granulation and direct compression, respectively. The stability of NM-T-SD was examined during a 2-month storage period (40°C, RH 75%). The results showed that the dissolution of NM-T-SD was slightly reduced after 2 months storage (40°C, RH 75%), which implied that aging occurred to some degree. However, no NM crystals could be observed by PXRD after 2 months storage for NM-T-SD (F11) prepared by direct compression.