Measurement and Correlation of Solid Drugs Solubility in Supercritical Systems

Abstract

A dynamic experimental set-up was utilized to measure ibuprofen solubility in supercritical CO2 at the pressure range of 8-13 MPa and the temperatures of 308, 313 and 318 K. Mole fraction values varied from 0.015×10−3 to 3.261×10−3 and correlated by using seven different semi empirical equations of state (Bartle, Modified Bartle, Mendez-Teja, Modified Mendez-Teja, Kumar-Johnson, Sung-shim and Gordillo) as well as seven cubic equations of state (van der Waals, Redlich-Kwong, Soave-Redlich-Kwong, Peng-Robinson, Stryjek-Vera, Patel-Teja-Valderana and Pazuki). Single and twin-parametric van der Walls mixing rules (vdW1, vdW2) were applied in order to estimate the supercritical solution properties. The physicochemical properties were also obtained using Joback, Lydersen and Ambrose methods. Absolute average relatives deviation (AARD) were calculated and compared for all the correlating systems. Results showed that among the cubic equations of state (EOSs) the Pazuki equation (AARD19.85% using vdW1 and AARD8.79% using vdW2) and SRK equation (AARD19.20% using vdW1 and AARD10.03% using vdW2) predicted the ibuprofen solubility in supercritical CO2 with the least error in comparison to the others. Among the semi-empirical EOSs the most desirable deviation (AARD<10%) was obtained by using Modified Bartle and Modified Mendez-Teja equations in all the studied temperatures.