| Popis: |
2 years ago it was recommended (2) that carotene be adopted as the provisional standard for vitamin A. In the preparation of carotene solutions for administration to animals, the solvent employed is important because of the unstable character of. carotene. A study of the stability of carotene in various solvents and under different conditions was suggested by this instability. The investigations of Schertz (3), Hume and Smedley-MacLean (4), Olcovich and Mattill (5), and Turner and Loew (6), show that solutions of carotene in absolute ether, ethyl oleate, ethyl laurate, and oleic acid deteriorate rapidly. Solutions in absolute alcohol, petroleum ether, paraffin oiI, olive oil, cottonseed oil, and hardened cottonseed oil were relatively stable. Addition of small quantities of hydroquinone to the carotene was found to stabilize the solutions. Since the preliminary report of this work was presented (1) Baumann and Steenbock (7) have published results on the stability of carotene in vegetable oils, esters, and organic solvents. Wesson oil was outstanding among the vegetable oils. Ethyl acetate, ethyl succinate, ethyl alcohol, and methyl alcohol were the most satisfactory of the esters and other organic solvents. For the present study the following solvents were selected: three highly purified esters (ethyl butyrate, ethyl Iaurate, and ethyl palmitate), one liver oil (medicinal cod liver oil), and three refined vegetable oils (maize oil, peanut oil, and Wesson oil). Solutions of 0.05 per cent of carotene in these solvents were prepared by warming to about 30” for a few minutes. The solutions were |
