Separation of pharmaceutical products with reverse micelles

Reverse micelle extraction has received considerable attention in recent years due to its ability to selectively solubilise solutes from an aqueous phase and to maintain their biological activities. This paper presents the results from studies on extraction of penicillin G from aqueous solution (forward extraction) and from reverse micelles to a new aqueous solution (backward extraction), by employing the principle of liquid-liquid extraction with reverse micelles. AOT is used as a surfactant and isooctane is used as an organic phase. The effect of pH, salt concentration, AOT concentration, and initial penicillin concentration on the penicillin forward and backward transfer at 21ºC was studied. The results show that the solubilisation of penicillin in the forward extraction is dependent on both pH and surfactant concentration. The backward extraction is dependent on ionic strength, surfactant concentration and the initial amount of penicillin in the organic phase before backward extraction. Despite successful results in the backward extraction, the overall extraction yield of penicillin is found to be less than the initial amount of penicillin before forward extraction due to difficulties during the forward extraction process.