Abstract
            Purpose: The objective of this work was to formulate casein (CAS) nanocarriers for the dissolution  enhancement of poorly water soluble drug celecoxib (CLXB).  
  Methods: The CLXB loaded CAS nanocarriers viz., nanoparticles, reassembled CAS micelles  and nanocapsules were prepared using sodium caseinate (SOD-CAS) as a carrier to enhance the  solubility of CLXB. The prepared formulations were characterized for particle size, polydispersity  index, zeta potential, percentage entrapment efficiency, and surface morphology for the selection  of best formulation. Fourier transform infrared spectroscopy, differential scanning calorimetry  and X-ray powder diffraction study was used to for the confirmation of encapsulation of CLXB.  Further, in vitro drug dissolution, ex-vivo permeation studies on chicken ileum and stability  studies were carried out.  
  Results: The CLXB loaded casein nanoparticles (CNP) (batch A2) showed a particle size diameter  216.1 nm, polydispersity index 0.422 with percentage entrapment efficiency of 90.71% and  zeta potential of -24.6 mV. Scanning electron microscopy of suspension confirmed globular  shape of CNP. The in vitro release data of optimized batch followed non Fickian diffusion  mechanism. The ex vivo permeation studies on chicken ileum of CLXB loaded CNP showed  permeation through mucous membrane as compared to pure CLXB. The apparent permeability  of best selected freeze dried CLXB loaded CNP (batch A2) was higher and gradually increased  from 0.90 mg/cm2  after 10 min to a maximum of 1.95 mg/cm2  over the subsequent 90 min. A  higher permeation was recorded at each time point than that of the pure CLXB.  
  Conclusion: The study explored the potential of CAS as a carrier for solubility enhancement of  poorly water soluble drugs.