BIOAVAILABILITY OF VITAMIN-A IN THE RAT FOLLOWING INGESTION OF NEOMYCIN SULFATE OR ALUMINUM HYDROXIDE

The objective of the present paper was to study the interaction of Neo mycin and aluminium hydroxide with vitamin A in terms of the effect of these drugs on the bioavailability of vitamin A in the rat. Bioavaila bility was determined on the basis of the effects of the drugs on grow th and on the plasma and hepatic levels of the vitamin. Vitamin A defi cient animals were used in assay 1 and normal animals in assay 2. In e ach assay the animals were divided into 3 groups: one received Neomyci n sulfate (0.1% in the diet), the second received aluminium hydroxide (0.05% in the diet) and the third (control) received no drug. Each of these three groups was subdivided into two groups receiving two differ ent concentrations of vitamin A palmitate. The bioavailability of vita min A was estimated by the parallel line method from the concentration of vitamin A in the diet and in the liver of the animals. No signific ant differences in growth or plasma retinol levels were observed betwe en the groups of animals studied in assays 1 and 2. Total vitamin A co ncentration in the liver of the animals which received Neomycin was lo wer (p<0.05) than that observed in the controls. Neomycin reduced the bioavailability of vitamin A by 13.9% (maximum, 18.1% and minimum, 9.6 %) in assay 1 and by 13.5% (maximum, 17.7% and minimum, 9.3%) in assay 2. Aluminium hydroxide at the level tested did not affect the bioavai lability of vitamin A.