Preparation, Characterizaton and Dissolution Kinetics of Celecoxib : beta and HP beta Cyclodextrin ComplexesAuthor(s): K. P. R. Chowdary and Lingaraj S. Danki
Celecoxib, a specific inhibitor of cycloxygenase-2 (COX-2) is poorly water soluble nonsteroidal anti-inflammatory drug with relatively low bioavailability. The effect of 9-cyclodextrin (9CD) and hydroxypropyl 9-cyclodextrin (HP9CD) on the aqueous solubility and dissolution rate of celecoxib was investigated. The phase solubility studies indicated that the solubility of celecoxib was significantly increased in the presence of 9-cyclodextrin and hydroxypropyl 9-cyclodextrin and was classified as ALtype, indicating the 1 : 1 stoichiometric inclusion complexes in water. Solid complexes were prepared by kneading method using 9-cyclodextrin and hydroxypropyl 9-cyclodextrin. The complexes formed were quite stable. Solid inclusion complexes of celecoxib : 9-cyclodextrin and celecoxib : hydroxypropyl 9- cyclodextrin were prepared in 1 : 1, 1 : 2 and 1 : 3 weight ratios. In vitro studies showed that the solubility and dissolution rate of celecoxib were significantly improved by complexation with 9- cyclodextrin and hydroxypropyl 9-cyclodextrin with respect to pure drug alone. The celecoxib : 9CD (1 : 3) inclusion complex yielded a 20 fold increase in the dissolution rate of celecoxib where as the celecoxib : HP9CD (1 : 3) inclusion complex yielded a 21 fold increase in the dissolution rate of celecoxib, when compared with pure drug. Solid complexes prepared were characterized by differential scanning calorimetry, powder x-ray diffractometry, scanning electron microscopy and IR studies.