Preparation and characterization of solid dispersions of celecoxib obtained by spray-drying ethanolic suspensions containing PVP-K30 or isomalt

Abstract

Celecoxib (CLX) is an anti-inflammatory drug that is used for acute pain treatment, but it has very low oral bioavailability owing to its poor water solubility. In this study, CLX solid dispersions are prepared by spray-drying using hydrophilic carriers with the aim of improving its apparent solubility and dissolution rate. Blends with different ratios of CLX, isomalt (ISO) and PVP were prepared in ethanol, and solid dispersions were obtained using a spray dryer. The saturation solubility and dissolution kinetics in 0.25% SLS and 0.04 M Na3PO4 containing media were determined. Also, SEM, DSC, XRPD, and stability studies were used to characterize the systems. Physicochemical analysis demonstrated the presence of amorphous CLX in the spray dried samples. The saturation solubility and dissolution rate of CLX from these formulations were higher than those for pure celecoxib and its physical mixtures. Amorphous CLX showed a lower dissolution rate compared to its crystalline form in 0.25% SLS medium, while this tendency was reversed under alkaline conditions. The CLX:PVP:ISO 3:5:2 spray dried sample showed the highest dissolution rate in both media. Exposure of samples to high moisture (75% humidity) recrystallized some of the amorphous CLX. Thus, the results showed that the dissolution rate of CLX was enhanced in 0.25% SLS, whereas a reduction in dissolution rate was observed in 0.04 M Na3PO4.