Colonic delivery of sodium butyrate via oral route: Acrylic coating designof pellets and in vivo evaluation in rats

Few pharmaceutical studies, with the exception of those on rectal solutions , are described on short chain fatty acid (SCFA) formulations-especially fo r sodium butyrate, which is a colonocyte preferential substrate. Highly dos ed butyrate pellets (90%) were prepared and their coating was designed for colonic delivery. In vivo determination (pH and transit time of pellets in rats) allowed to respectively choose the grade and thickness (resistance of 6 h) of the pH-dependent coating (Eudragi (R) L+S, 1: 1). The coated pelle ts were administered to naturally butyrate-deprived rats. The rats' colonic mucosa had the particularity to weakly express mitochondrial HMG-CoA synth ase, an enzyme that responds to luminal butyrate. The results did not show early absorption of butyrate, but a probable cecal loss in the rat cecum as cecal residence time of the pellets was important and as pH was propitious for the coating hydrolysis. It seemed that butyrate, given daily for 7 day s without the other main SCFA, was unable to induce the enzyme and/or that the close (0.32 mmol/day) was insufficient. (C) 2001 Prous Science. All rig hts reserved.