Application of tritium thermal activation method for labeling of isoniazide

Full text: For labeling of pharmacological preparation of isoniazide we used the method of labeling by thermally activated tritium. Isoniazide was labeled by thermally activated tritium in apparatus for tritium labeling. The influence of procedure of labeling on isoniazide has been investigated. During of labeling the change of color of izoniazide was revealed, that indicates on partial destruction of izoniazide. The optimum regime of labeling was selected. The system of purification of tritium-labeled izoniazide by thin layer chromatography (TLC) has been developed. Tritium-labeled preparation of izoniazide was purified by TLC on silicagel in the ethyl acetate system: isopropanol: liquid ammonia (concentrated): acetone (15:20:5:2). Application of TLC for purification of tritium-labeled preparation allows complete purification of izoniazide from by-products. The output of purified tritium-labeled preparation of izoniazide was 41.4%. The received preparation had specific radioactivity of 468.5 MBq/mmol, radiochemical purity of the preparation was 95 %. TLC purification seems to be an inexpensive and fast method, suitable for purification of tritium-labeled izoniazide. Thus, the used method allows obtaining of tritium-labeled preparation of izoniazide, suitable for medical and biologic researches. Received tritium-labeled preparation of izonizide is supposed to be used in studies of binding capacity of blood transport proteins of patients with various pathological conditions. (authors)