Residual Solvents in Drugs

Technique Used:  Static Headspace coupled with GC/MS

A pharmaceutical manufacturer wanted to know whether a solvent (ethanol) used in their process was present in a powdered drug. Static headspace and gas chromatography/mass spectrometry (GC/MS) were used to identify and quantify the amount of any ethanol present. The resultant gas chromatogram of the drug (top figure) shows a possible solvent peak at a retention time of approximately 1.67 min. The peak is positively identified as ethanol from its mass spectrum (bottom figure). The amount of ethanol was quantified using a one-point standard.