抄録
Vitamin A values of the sample containing all-trans vitamin A only and the samples containing all-trans vitamin A and neovitamin A (confirmed by thin-layer chromatography) were estimated by the methods of USP XVI, BP 1960,BP 1963 and the modified method of JP VII. When the values estimated by USP XVI method and JP VII modified method were compared with those estimated by BP 1960 and 1963 methods on the sample containing all-trans vitamin A only, the former were about 1.5% lower than the latter. This might be due to the loss of vitamin A in the preparation of the unsaponifiable matter. When the values estimated by BP 1963 method were compared with those by the other methods on the samples containing all-trans vitamin A and neovitamin A, the former were 1 to 4 % higher than the latter. This might be due to the fact that BP 1963 method gave a little higher value than the calculated biological potency for neovitamin A.
