Phase diagram of ibuprofen with fatty acids

Drug formulation often implies the preparation of multicomponent systems based both on drug–drug and drug-excipient combinations. It is well-known that drug-excipient interactions can deeply influence the technological and biopharmaceutical properties of solid dosage forms. Thermal analysis is often employed to evidence such interactions. Using Differential scanning calorimetry, we have determined two binaries solid–liquid phase diagram for ibuprofen (1) + lauric acid (2) and ibuprofen (1) + palmitic acid (2) mixtures. The eutectic temperature is also measured. Group-contribution model (UNIFAC, versions modified) is used to predict the diagram. The excipient, Lauric Acid and Palmitic Acid, were found to form simple eutectics with ibuprofen, and deviations were observed between experimental and predicted solid–liquid equilibria.