Pharmacokinetics and tissue distribution of inositol hexaphosphate in C.B17 SCID mice bearing human breast cancer xenografts.

Inositol hexaphosphate (IP(6)) is effective in preclinical cancer prevention and chemotherapy. In addition to cancer, IP(6) has many other beneficial effects for human health, such as reduction in risk of developing cardiovascular disease and diabetes and inhibition of kidney stone formation. Studies presented here describe the pharmacokinetics, tissue distribution, and metabolism of IP(6) following intravenous (IV) or per os (PO) administration to mice. SCID mice bearing MDA-MB-231 xenografts were treated with 20 mg/kg IP(6) (3 μCi per mouse [(14)C]-uniformly ring-labeled IP(6)) and euthanized at various times after IP(6) treatment. Plasma and tissues were analyzed for [(14)C]-IP(6) and metabolites by high-performance liquid chromatography with radioactivity detection. Following IV administration of IP(6), plasma IP(6) concentrations peaked at 5 minutes and were detectable until 45 minutes. Liver IP(6) concentrations were more than 10-fold higher than plasma concentrations, whereas other normal tissue concentrations were similar to plasma. Only inositol was detected in xenografts. After PO administration, IP(6) was detected in liver; but only inositol was detectable in other tissues. After both IV and PO administration, exogenous IP(6) was rapidly dephosphorylated to inositol; however, alterations in endogenous IPs were not examined.