Celecoxib Crystallized from Hydrophilic Polymeric Solutions Showed Modified Crystalline Behavior with an Improved Dissolution Profile

Comparison of two self-nanoemulsifying drug delivery systems using different solidification techniques for enhanced solubility and oral bioavailability of poorly water-soluble celecoxib

In this study, we aimed to develop a solid self-nanoemulsifying drug delivery system (S-SNEDDS) and a solid self-nanoemulsifying granule system (S-SNEGS) to enhance the solubility and oral bioavailability of celecoxib. This process involved the preparation of a liquid SNEDDS (L-SNEDDS) and its subsequent solidification into a S-SNEDDS and a S-SNEGS. The L-SNEDDS consisted of celecoxib (drug), Captex® 355 (Captex; oil), Tween® 80 (Tween 80; surfactant) and D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS; cosurfactant) in a weight ratio of 3.5:25:60:15 to produce the smallest nanoemulsion droplet size. The S-SNEDDS and S-SNEGS were prepared with L-SNEDDS/Ca-silicate/Avicel PH 101 in a weight ratio of 103.5:50:0 using a spray dryer and 103.5:50:100 using a fluid bed granulator, respectively. We compared the two novel developed systems and celecoxib powder based on their solubility, dissolution rate, physicochemical properties, flow properties and oral bioavailability in rats. S-SNEGS showed a significant improvement in solubility and dissolution rate compared to S-SNEDDS and celecoxib powder. Both systems had been converted from crystalline drug to amorphous form. Furthermore, S-SNEGS exhibited a significantly reduced angle of repose, compressibility index and Hausner ratio than S-SNEDDS, suggesting that S-SNEGS was significantly superior in flow properties. Compared to S-SNEDDS and celecoxib powder, S-SNEGS increased the oral bioavailability (AUC value) in rats by 1.3 and 4.5-fold, respectively. Therefore, S-SNEGS wolud be recommended as a solid self-nanoemulsifying system suitable for poorly water-soluble celecoxib.

Modification of microenvironmental pH of nanoparticles for enhanced solubility and oral bioavailability of poorly water-soluble celecoxib

This study aimed to develop a novel pH-modified nanoparticle with improved solubility and oral bioavailability of poorly water-soluble celecoxib by modifying the microenvironmental pH. After assessing the impact of hydrophilic polymers, surfactants and alkaline pH modifiers on the drug solubility, copovidone, sodium lauryl sulfate (SLS) and meglumine were chosen. The optimal formulation of solvent-evaporated, surface-attached and pH-modified nanoparticles composed of celecoxib/copovidone/SLS/meglumine at weight ratios of 1:1:0.2:0, 1:0.375:1.125:0 and 1:1:1:0.2:0.02, respectively, were manufactured using spray drying technique. Their physicochemical characteristics, solubility, dissolution and pharmacokinetics in rats were evaluated compared to the celecoxib powder. The solvent-evaporated and pH-modified nanoparticles converted a crystalline to an amorphous drug, resulting in a spherical shape with a reduced particle size compared to celecoxib powder. However, the surface-attached nanoparticles with insignificant particle size exhibited the unchangeable crystalline drug. All of them gave significantly higher solubility, dissolution, and oral bioavailability than celecoxib powder. Among them, the pH-modified nanoparticles demonstrated the most significant improvement in solubility (approximately 1600-fold) and oral bioavailability (approximately 4-fold) compared to the drug powder owing to the alkaline microenvironment formation effect of meglumine and the conversion to the amorphous drug. Thus, the pH-modified nanoparticle system would be a promising strategy for improving the solubility and oral bioavailability of poorly water-soluble and weakly acidic celecoxib.