The effect of some acrylic polymers on dissolution of celecoxib solid dispersion formulations

Abstract

Objective The purpose of the present study was firstly to identify the effectiveness of Eudragit® polymers (Eudragit® RL, RS, L100-55, L100, S100 and E100) in inhibition of celecoxib precipitation from buffer solutions (pH = 6.8). Furthermore, the influence of Eudragit® polymers on non-sink dissolution behavior of celecoxib from solid dispersions was investigated. Methods Solid dispersions were prepared by the rotary evaporation method. In vitro dissolution studies, FT-IR and differential scanning calorimetry were employed to characterize the formulations. Results The results revealed that Eudragit® E100, L100 and S100 inhibited precipitation of celecoxib efficiently. It is understood that crystallization during the dissolution of solid dispersions could happen through crystallization from solid matrix following contact with the dissolution medium or from the supersaturated solution produced following dissolution. The supersaturated drug concentrations attained from the dissolution of Eudragit®-celecoxib solid dispersions were almost similar, suggesting that crystallization from solid matrix did not occur readily. However, only solid dispersions containing efficient crystallization inhibitor polymers were able to maintain the supersaturated solution up to the end of the dissolution run. Conclusion Results revealed that the principal mechanism of attaining supersaturated solution of celecoxib from solid dispersions was related to crystallization inhibition from solution not from solid matrix.