A RAPID METHOD FOR DETERMINATION OF VITAMINS D 2 AND D 3 IN PHARMACEUTICAL PREPARATIONS BY HPLC K. Sarioglu, 1 S. S. Celebi, 2 and M. Mutlu 1, * 1 Department of Food Engineering, 2 Department of Chemical Engineering, Hacettepe University, 06532 Ankara, Turkey ABSTRACT In this study, a rapid, simple, and economical reversed phase liquid chromatographic method was described for the determina- tion of vitamin D 2 and vitamin D 3 in pharmaceutical preparations. The pharmaceutical formula of vitamin D 2 is prepared by mixing with filling material, and that of vitamin D 3 is prepared by dissolv- ing in herbal oil. Before injection to HPLC the vitamin D 2 sample was extracted with diethyl ether and the extract was cleaned by centrifugation; the vitamin D 3 sample was prepared by dissolving it in an appropriate amount of tetrahydrofuran (THF). The vitamin content of vitamin D 2 and vitamin D 3 samples was determined by reversed phase liquid chromatography. Ultra Violet-Visible (UV-VIS) detector and C-18 column were used for this purpose. Vitamin D 2 and impurities were completely resolved by the mixture of methanol-acetonitrile as mobile phase with a flow rate of 1.0 mL/min. 973 Copyright © 2001 by Marcel Dekker, Inc. www.dekker.com J. LIQ. CHROM. & REL. TECHNOL., 24(7), 973–982 (2001) * Corresponding author. E-mail: gmehmet@eti.cc.hun.edu.tr