Preparation and evaluation of celecoxib nanosuspensions for bioavailability enhancement

Celecoxib (CLX) is a selective cyclooxygenase-2 (COX-2) inhibitor; however, the application of CLX is compromised due to its poor aqueous solubility and low oral bioavailability. This study aims to develop a nanotechnology to overcome these issues. Celecoxib nanosuspensions (CLX-NS) were formulated using D-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) as stabilizer via high pressure homogenization (HPH) and then freeze-dried to solid powder. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the physicochemical and pharmaceutical properties of CLX-NS lyophilization. In vitro dissolution, an in situ single-pass intestinal perfusion study, and in vivo pharmacokinetic studies were performed for further investigation. Particles of the nanosuspensions were short-rod shaped (similar to 388 nm) and remained in the same crystalline state as CLX coarse powder. In the test of in vitro dissolution, CLX-NS displayed a higher dissolution amount (90.8% during 60 minutes) compared to groups of CLX coarse powder (47.9%) and physical mixture (52.9%). Moreover, in situ single-pass intestinal perfusion study indicated that CLX-NS could be well absorbed in the whole intestine with the main absorption site being the duodenum. Significant improvements in C-max and AUC(o-t) of CLX-NS were obtained in pharmacokinetic analyses with a 245.8% increase in relative bioavailability compared to CLX coarse powder. This study showed that nanosuspension preparations could be a promising strategy in influencing CLX absorption in gastrointestinal tract, and improving dissolution and oral bioavailability of poorly water-soluble drugs.