Formulation Development and Characterization of Rilpivirine Nanosuspension for Improved Solubility by Nanomilling

The objective of this study was to formulate and optimize a stable rilpivirine nanosuspension. In the present study, yttrium stabilized zirconium oxide beads being used as the milling media in nanomilling process. The lyophilized nanocrystals were being characterized by particle size distribution (PSD), polydispersity index (PDI), X-ray diffraction (XRD) and FTIR (Fourier transform infrared spectroscopy). Optimized nanosuspension has mean particle diameter of 266 nm, PDI of 0.158, zeta potential of 22.1 mV and spherical in shape with surface oriented stabilizer molecules. Flow properties like sedimentation volume, poura-bility with the F value of 0.94 and also the redispersability even after 4 weeks of storage was found to be satisfactory for the optimized nano-suspension. Many folds increase in solubility and rate of drug release observed, The lyophilized nanocrystals retains its crystallinity after nanomilling, stable chemically with high drug content, therefore, the developed nanosuspension would be an alternative better formulation than its conventional formulation to address its bioavailability issue. However, this should be further confirmed by appropriate techniques in vivo studies.