Nanosuspensions of poorly soluble drugs: preparation and development by wet milling

Nanosizing techniques are important tools for improving the bioavailability of water insoluble drugs. Here, a rapid wet milling method was employed to prepare nanosuspensions: 4 types of stabilizers at 4 different concentrations were tested on 2 structurally different drug compounds: indomethacin and itraconazole. Photon correlation spectroscopy (PCS) results showed that the finest nanosuspensions were obtained when 80 wt% (to drug amount) pluronic F68 was the stabilizer for indomethacin and 60 wt% pluronic F127 for itraconazole. Compared to physical mixtures, dissolution rates of the nanosuspensions showed significant increases. The morphology of nanoparticles was observed by transmission electron microscopy (TEM). Crystalline state of the drugs before and after milling was confirmed using differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). The physical and chemical stabilities of the nanosuspensions after storage for 2 months at room temperature and at 4°C were investigated using PCS, TEM and HPLC. No obvious changes in particle size and morphology and no chemical degradation of the drug ingredients were seen.