Recent developments in the determination of residual solvents in pharmaceutical products by microextraction methods

Residual solvents, or organic volatile impurities, are a potential toxic risk for drugs and pharmaceutical products and have been a concern of manufacturers for many years. This review is to describe and discuss applications of microextraction techniques for the extraction of such volatiles for pharmaceutical product analysis. For better clarification, micro-extraction techniques applied for this purpose are divided into two categories of solid phase microextraction and solvent-based (i.e. single drop and dispersive liquid-liquid) micro-extraction. As can be seen below, attempts to employ these techniques for the determination of residual solvents in pharmaceutical products are mainly reported in recent years, after their better development, therefore not too many references can be found to be included in this first review article. To enable the routine application of different modes of microextractions techniques to real-world problems, more operational convenience and some form of automation would be needed, especially for solvent-based microextractions.