A rapid method for determination of vitamins D-2 and D-3 in pharmaceuticalpreparations by HPLC

In this study, a rapid, simple, and economical reversed phase liquid chroma tographic method was described for the determination of vitamin D-2 and vit amin D-3 in pharmaceutical preparations. The pharmaceutical formula of vita min D-2 is prepared by mixing with filling material, and that of vitamin D- 2 is prepared by dissolving in herbal oil. Before injection to HPLC the vit amin D-2 sample was extracted with diethyl ether and the extract was cleane d by centrifugation; the vitamin D-3 sample was prepared by dissolving it i n an appropriate amount of tetrahydrofuran (THF). The vitamin content of vitamin D-2 and vitamin D-3 samples was determined b y reversed phase liquid chromatography. Ultra Violet-Visible (UV-VIS) detec tor 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. The best resolution of vitamin D-3 from interferences could be achieved by the gradient mixture of methanol and THF as the mobile phase at 1.0 mL/min flow rate. Mean recoveries of vitamin D-2 ranged from 99.65% to 105.48% with an overal l mean of 102.54% for different spilling levels. The limits of detection fo r vitamin D-2 and vitamin D-3 in their preparation were found to be <0.43 < mu>g/g and <1.02 <mu>g/mL respectively.