Effect of Skimmed Milk on the Absorption and Metabolism of 5-Fluorouracil (5-FU) in Animals

Several modalities of drug administration have been investigated to improve bioavailability and to reduce 5-FU related toxicity. The aim of present study was to evaluate the effect of skimmed milk on the absorption and metabolism of 5-FU in rabbits, mice and dogs. It was further aimed to determine its route related toxicity in rabbits. Plasma concentration of both 5-FU and its metabolite 5-Fluoro-2-deoxyuridine (5-Fdurd) was determined using HPLC. The absorption of 5-FU co-administered with skimmed milk was significantly higher as compared to its co-administration with water in rabbits and mice (p < 0.001), whereas no significant difference was observed in dogs. The plasma concentration of 5-Fdurd a major metabolite of 5-FU was significantly higher in water group when compared with skimmed milk group in rabbits and mice (p < 0.05), whereas no significant difference was observed in dogs. Route related toxicity was also determined in rabbits. Various hematological parameters were studied at 4th and 7th day after oral and intravenous administration of 5-FU. WBCs count was significantly decreased in intravenous group as compared to control and oral groups (p < 0.001). It was concluded that co-administration of skimmed milk with 5-FU increases its absorption and reduces its metabolism. Skimmed milk also reduces 5-FU related toxicity in rabbits.