Synergistic Effect of Ultrasound Assisted Extraction and Two-phase Systems on the Recovery of Penicillin G from Water

Penicillin G (Peni G) is a molecule of high interest for pharmaceutical use, but a purification process is required. In this work, phase diagrams of aqueous two-phase systems (ATPS) containing Polyethylene glycol (PEG-6000) - Sodium citrate - water as well as the partitioning behaviour of penicillin G in these systems are presented. The effect of different parameters on extraction conditions such as salt (type and concentration), polyethylene glycol molecular weight and concentration, temperature, pH of buffer solution, volume ratio and the effect of ultrasound were evaluated and optimized. Aqueous two-phase systems of PEG-6000 37.5% (w/w)/ citrate buffer solution 28.5% (w/w) with a ratio of 2/1, pH 6.16, and at room temperature (22°C), assisted by ultrasound (20 kHz value of frequency) is shown to be an effective way of separating and concentrating penicillin G from an aqueous phase and also gives a reduced consumption of time and organic solvents. In those conditions, separation efficiency is upper than 99% compared with liquid/liquid extraction 85%.