Milk as a Drug Analysis Medium: HPLC Determination of Isoniazid

The use of milk as a medium for drug analysis in a graduate-laboratory experiment is proposed. This project, designed with an interdisciplinary approach, gives the students the opportunity to safely manipulate biological fluids and to learn their basics. The experiment is modeled on a real-life analytical problem, aimed at determining the isoniazid content in milk using simple HPLC equipment. The methodology requires the derivatization of isoniazid with cinnamaldehyde to form a hydrazone suitable for UV detection. The present method could easily be adapted to other drug analysis. Details of the experimental procedure are described along with representative student results. This experiment provides experience in quantitative chromatographic techniques and in the chemical treatment of biological fluids.