Influence of polymeric excipients on the solubility of aspirin: Experimental measurement and model prediction

In this work, the solubility of aspirin at 293.15-313.15 K was measured in several aqueous systems where one excipient out of PEG 6000, PEG 400, PVP K25, HPMC E3 and poloxamer 188 was present. It was found that PVP K25 had the strongest solubilizing ability and the solubility enhancement of aspirin by poloxamer 188 was greatly affected by temperature. In addition, the Wilson, NRTL and UNIQUAC models were employed to predict the solubility of aspirin in various organic solvents as well as in different mixtures of polymeric excipients and water through interaction parameters obtained from experimental data. The average ARDs of Wilson, NRTL, and UNIQUAC models were 0.0300, 0.0318, 0.0305 for the binary aspirin-solvent systems, respectively, and those were 0.4214, 0.1166, 0.0861 for the ternary aspirin-polymer-water systems. UNIQUAC model among these three models was found to have excellent performance for solubility prediction of aspirin in solvents and polymer-water solutions. (C) 2019 Elsevier B.V. All rights reserved.