A method via the observation of the first and last melting points (FLMP) of solids is proposed to measure solid-liquid-gas (SLG) equilibrium for the ibuprofen + myristic acid + CO2 and ibuprofen + tripalmitin + CO2 tertiary systems. The temperature-composition (T, w) data as well as the eutectic compositions at different pressures (0.1, 6.0, 10.0, and 15.0) MPa were determined. Results indicate that the two systems arc both simple eutectic at (0. 1 and 6.0) MPa, while the phase diagrams transform into the solid Solution as the pressure increases. The eutectic composition of the ibuprofen + myristic acid + CO2 system is nearly constant (about 0.5 mass fraction of ibuprofen), while that of the ibuprofen + tripalmitin + CO2 system increases from 0.4 (mass fraction of ibuprofen) at 0.1 MPa to 0.6 at 15.0 MPa. T, w data at 0.1 MPa from FLMP are in good agreement with those determined by differential scanning calorimetry (DSC) and also with predictions from the ideal Solubility equation.