Improvement of physical stability and dissolution rate of celecoxib suspensions by complexation with beta-cyclodextrins.

Solid dispersions of celecoxib with beta-cyclodextrins were prepared by physical mixing, slugging and kneading methods at 1:1 and 1:2 molar ratios and characterized by differential scanning calorimetry. Celecoxib suspensions were formulated employing its solid dispersions with sodium carboxymethylcellulose as the suspending agent. Stability studies were conducted by subjecting all the suspensions to freeze-thaw cycling. The suspensions were evaluated for particle size, sedimentation volume, viscosity, redispersibility and dissolution rate initially and after stability testing. Celecoxib suspensions formulated employing its solid dispersions exhibited good physical stability and gave higher dissolution rates than those formulated with celecoxib alone. The suspension prepared from solid dispersions (1:2) by the kneading method gave the highest improvement in dissolution rate and efficiency. Celecoxib in the inclusion complex with beta-cyclodextrin produced suspensions of better physical stability and dissolution rate.