Solubility studies on the antibiotic penicillin V using supercritical fluids

Supercritical fluid extraction is receiving widespread attention as a possible separation process for the food and pharmaceutical Industries since it can be conducted at near-ambient conditions with non-toxic solvents. This study is concerned with investigating the feasibility of separation and isolation of penicillin V using supercritical fluids. A flow apparatus has been constructed and used to determine the high pressure solid-fluid equilibrium solubilities. An absorption spectroscopic method is used to analyze the sample solutions. The solubility of penicillin V in supercritical Carbon dioxide has been measured from 314.85 K to 334.85 K and from 1144 psig to 4050 psig. The solubility ranges from 5.2 x 10^{5 to 5.6 x 104 mole fraction. It was determined that penicillin V can dissolve In supercritical carbon dioxide at concentrations 106-108 greater than that predicted by the ideal gas law. The problems associated with penicillin V and mixed solvents are discussed. The equilibrium solubility is correlated using a compressed gas model with the Peng-Robinson equation of state. The unknown physical properties of penicillin V are estimated using group contribution methods. This model correlates penicillin V solubilities within about 60 %.}