Stable and short-lived isotopes in the study of tissue distribution

Two relatively novel techniques that are utilized in the study of tissue distribution of drugs are discussed. The first technique, GC-MS fragmentography, provides an opportunity for the identification and quantification of several compounds and internal standards, in the same analysis, at picogram to nanogram amounts. The second technique utilizes short-lived radioisotopes and external scintigraphy. This approach can continuously monitor the tissue and organ distribution of an appropriately labeled compound. It produces quantifiable results and provides an opportunity for doing several experiments on the same animal in a noninvasive manner.