Determination of vitamin A, vitamin E, and their esters in tablet preparations using supercritical fluid extraction and HPLC

A rapid and precise method for the isolation of vitamins A and E and their acetate or palmitate esters from tablet matrices was developed using supercritical fluid extraction (SFE). The vitamins were analyzed by nonaqueous reversed-phase high-performance liquid chromatography after a 15- min extraction of the dosage form with supercritical carbon dioxide at 40 °C and at a pressure of 250 atm. A quantitative comparison of SFE with an established liquid extraction procedure was performed on commercial tablet formulations. Vitamin recoveries of over 95.6% compared with conventional liquid extraction were achieved by the SFE technique with a much shorter sample preparation time (15 min vs 2 h). Moreover, the automated SFE process minimized the number of sample handling operations, drastically reduced the consumption of harmful solvents, and provided mild extraction conditions for the analysis of the labile vitamins. The described SFE method is suitable for quality control analyses of pharmaceutical tablets.