QUALITATIVE INVESTIGATION OF UPTAKE OF FINE-PARTICLE SIZE MICROCRYSTALLINE CELLULOSE FOLLOWING ORAL-ADMINISTRATION IN RATS

A subchronic toxicity study was conducted to evaluate the potential to xicological effects associated with intestinal translocation of a spec ial fine particle size (median particle size 6 mu m) microcrystalline cellulose (MCC). Four groups of Sprague-Dawley rats (20/sex/group) rec eived either 0 (control), 500, 2500 or 5000 mg/kg/day MCC (25 % w/v in tap water) daily by oral gavage for 90 d. At study termination, organ s and tissues from high-dose and control animals, including multiple s ections of intestine with gut-associated lymphoid tissue, were process ed for light microscopy with subsequent examination under polarised li ght for the presence of birefringent MCC particles. None were observed in any tissue examined. No toxicologically significant effects or les ions were found in any other parameter or organ evaluated. The 'no obs erved adverse effect level' (NOAEL) for toxicological effects was grea ter than 5000 mg/kg/day MCC, which was the highest dosage tested. Thes e results further verify the safety of commercial MCC products for use in food and pharmaceutical applications.