Impact of co-administration of protonated nanostructured aluminum silicate (cholesterol absorption inhibitor) on the absorption of lipid soluble vitamins D3 and K1: An assessment of pharmacokinetic and in vitro intraluminal processing

Abstract Protonated nanostructured aluminum silicate (NSAS) is a protonated montmorillonite clay that was shown to be effective as an inhibitor of intestinal cholesterol absorption. The effect of NSAS on the intestinal absorption of nutrients is unknown. An in vitro lipolysis model was adapted to test the intraluminal processing of vitamin D 3 and K 1 in the presence of various amounts of NSAS. Additionally, vitamin absorption was assessed in male Sprague-Dawley rats randomized in the following treatment groups: IV administration of 0.1 mg/kg vitamin D 3 and 1 mg/kg vitamin K 1 , and a single-dose gavage of 1 mg/kg vitamin D 3 and 5 mg/kg of vitamin K 1 in peanut oil with various doses of NSAS slurry, 2% NSAS-fortified diet, or 50 mg/kg stigmastanol. The solubilized fraction of vitamin D 3 in the lipolysis medium was reduced from 70% to 46% upon the addition of 120 mg NSAS. In contrast, the solubilized fractions of vitamin K 1 were not significantly affected. Although the NSAS-fortified diet did not significantly affect the absorbed fraction of both vitamins, NSAS slurry decreased the absorption of vitamin D 3 as compared to the control. These results indicate that NSAS may be incorporated in diet to treat hypercholesterolemia; however, vitamin D 3 monitoring may be required.