Preparation, stabilisation, isolation and tableting of valsartan nanoparticles using a semi-continuous carrier particle mediated process

This work investigated the technical feasibility of preparing, stabilizing and isolating poorly water-soluble drug nanoparticles via a small-scale antisolvent precipitation process operating in semi-continuous mode. Specifically, a novel semi-continuous process was demonstrated for the carrier particle mediated production, stabilization and isolation of valsartan nanoparticles into a solid form using montmorillonite clay particles as the carrier. The semi-continuous process operated robustly for the full duration of the experiment (~16 min) and steady-state conditions were reached after ~5 min. Nanoparticles of valsartan (51 ± 1 nm) were successfully prepared, stabilized and isolated with the help of montmorillonite (MMT) or protamine functionalized montmorillonite (PA-MMT) into the dried form by this semi-continuous route. The dissolution profile of the isolated valsartan nanocomposite solids was similar to that of valsartan nanocomposite solids produced via the corresponding laboratory scale batch mode process, indicating that the product quality (principally the nanoscale particle size and solid-state form) is retained during the semi-continuous processing of the nanoparticles. Furthermore, tablets produced via direct compression of the isolated valsartan nanocomposite solids displayed a dissolution profile comparable with that of the powdered nanocomposite material. PXRD, DSC, SSNMR and dissolution studies indicate that the valsartan nanoparticles produced via this semi-continuous process were amorphous and exhibited shelf-life stability equivalent to > 10 months.