Cloud Point Extraction in the Determination of Drugs in Biological Matrices

Cloud point extraction (CPE) is a simple, safe and environment-friendly technique used in the preparation of various samples. It was primarily developed for the assessment of environmental samples, especially analyzed for metals. Recently, this technique has been used in the extraction and determination of various chemical compounds (e.g., drugs, pesticides and vitamins), in various matrices (e.g., human plasma, human serum, milk and urine). In this review, we show that CPE is a reliable method of extraction and can be used in analytical laboratories in combination with other techniques that can be used in the determination of drugs and other chemicals in the human biological matrix. According to the literature, a combination of different methods provides good recovery and can be used in the simultaneous determination of many drugs in a single analysis. CPE can be optimized by changing its conditions (e.g., type of surfactant used, incubation temperature, pH and the addition of salts). In this review, we present the optimized CPE methods used in the determination of various pharmaceuticals and describe how the conditions affect the performance of extraction. This data might support future designing of the new CPE applications that are simple and more accurate. We compared CPE with other extraction methods and also showed the advantages and disadvantages of various extraction techniques along with a discussion on their environmental impact. According to the publications reviewed, it is obvious that CPE is an easy, safe, rapid and inexpensive method of extraction.