What's in a Tablet? Extraction and Spectroscopic Identification of Pharmaceutical Unknowns

Spectroscopic characterization of molecules is typically reinforced in the organic chemistry teaching laboratory via the analysis of reaction products by NMR and IR, and initial coverage of these topics can include experiments involving the identification of unknown compounds. To combine the unknown identification component with common laboratory techniques and relevant biologically active compounds, an experiment was developed allowing students to identify the active pharmaceutical ingredient present in various unknown tablets. The protocol involves pulverization of the unknown tablets, solid-liquid extraction, vacuum filtration, liquid-liquid extraction, and solubility tests prior to analysis via IR and NMR spectroscopy. Ultimately, this laboratory experiment provides a platform for students to reengage with many techniques covered in introductory organic chemistry laboratory experiments while gaining exposure and familiarity with spectroscopic methods.