Influence of hydrophilic polymers on celecoxib complexation with hydroxypropyl β-cyclodextrin

Complexation of celecoxib with hydroxypropyl beta-cyclodextrin (HP beta CD) in the presence and absence of 3 hydrophilic polymers-polyvinyl pyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), and polyethylene glycol (PEG)-was investigated with an objective of evaluating the effect of hydrophilic polymers on the complexation and solubilizing efficiencies of HP beta CD and on the dissolution rate of celecoxib from the HP beta CD complexes. The phase solubility studies indicated the formation of celecoxib- HP beta CD inclusion complexes at a 1:1M ratio in solution in both the presence and the absence of hydrophilic polymers. The complexes formed were quite stable. Addition of hydrophilic polymers markedly enhanced the complexation and solubilizing efficiencies of HP beta CD. Solid inclusion complexes of celecoxib-HP beta CD were prepared in 1:1 and 1:2 ratios by the kneading method, with and without the addition of hydrophilic polymers. The solubility and dissolution rate of celecoxib were significantly improved by complexation with HP beta CD. The celecoxib- HP beta CD (1:2) inclusion complex yielded a 36.57-fold increase in the dissolution rate of celecoxib. The addition of hydrophilic polymers also markedly enhanced the dissolution rate of celecoxib from HP beta CD complexes: a 72.60-, 61.25-, and 39.15-fold increase was observed with PVP, HPMC, and PEG, respectively. Differential scanning calorimetry and X-ray diffractometry indicated stronger drug amorphization and entrapment in HP beta CD because of the combined action of HP beta CD and the hydrophilic polymers.