Preparation and in vitro/in vivo evaluation of fenofibrate nanocrystals

The majority of the candidate drug entities exhibit solubility-limiting absorption. Nanocrystal suspensions with particle size in the nanometer scale (nanonization) can increase aqueous solubility and improve oral bioavailability. Regarding the importance of nanosuspension solidification, this study intended to study the critical parameters on redispersed particle size of dried nanocrystals as pretabletting material during spray drying process, such as supporting agents, inlet temperature and feed rate. Fenofibrate with poor water solubility and low melting point was used as a model drug. Nanocrystals of fenofibrate were prepared by a bead-milling method. Five types of hydrophilic excipients in combination with sodium dodecyl sulfate (SDS) were studied as supporting agents during spray drying. The resultant products were characterized by particle size analysis, scanning electron microscopy imaging, differential scanning calorimetry, X-ray powder diffraction and dissolution testing. Spray dried powder with a mean redispersed particle size of 699 nm was produced by using mannitol and SDS as supporting agent. Weight ratio (RF/m) of fenofibrate:mannitol and inlet temperature strongly influenced the particle size of the nanocrystals. The optimal inlet temperature and feed rate was optimized as 75 °C and 4 mL min(-1), respectively. Partially transformation of fenofibrate crystalline to the amorphous form was observed. The dissolution profiles of tablets prepared with the spray dried powder were similar to the commercial nanocrystal formulation Lipidil™ ez, and faster than that of the micronized formulation. The relative bioavailability of the spray-dried formulation was determined to be 89.6% taking Lipidil™ ez as the reference. There were no significant statistic differences of AUC0-72 and Cmax between the two formulations.