Influence of lanolin and white soft paraffin on the determination of vitamin A in fats

Pharmaceutical interaction of the most frequently used substances with fats : lanolin, white soft paraffin and vitamin A palmitate was studied. The mix tures were examined by TLC with different ratios of lanolin and vitamin A p almitate, and white soft paraffin and vitamin A palmitate. Vitamin A in the mixtures was determined by the UV spectrophotometric method according to B P 93. It was established that the rise of lanolin concentration resulted in an increased apparent content of Vitamin A in fats as a consequence of lan olin absorption at the wave length of maximum absorption of vitamin A. By a n increase of white soft paraffin concentration, an apparent decreased in t he content of vitamin A in fats was obtained. Therefore, the suggested UV s pectrophotometric method for vitamin A determination has a limited applicat ion on fats with high content of lanolin and white soft paraffin.