Assessing the plasma pharmacokinetics, tissue distribution, excretion and effects on cholesterol pharmacokinetics of a novel hydrophilic compound, FM-VP4, following administration to rats.

PURPOSE The purpose of this project was to 1) assess the disposition kinetics of [3H]-cholesterol following co-administration with a novel hydrophilic compound, FM-VP4, and 2) determine the pharmacokinetics, tissue distribution and excretion of [3H]FM-VP4 following single oral (150 mg/kg which includes 100 mCi of radiolabel) and intravenous (15 mg/kg which includes 10 mCi of radiolabel) doses. METHODS Following an overnight fast (12-16 h) and 48 h post-surgery, adult male Sprague Dawley rats were divided into six treatment groups (n=4/group). Groups received single oral doses of 25 mCi/ml [3H]cholesterol alone or with 5, 10, 20, 50 and 100 mg/kg FM-VP4 at 0700 h. Ten percent Intralipid was used to solubilize and co-administer [3H]-cholesterol and FM-VP4. LC-MS analysis confirmed minimal cholesterol and vegetable stanol content within 10% Intralipid. Thin layer chromatography was used to confirm that the majority of radioactivity measured in plasma was associated with either esterified or unesterified cholesterol. In a second study pharmacokinetics of [3H]FM-VP4 were studied following intravenous or orally gavaged doses (n=8). Tissues, urine and feces were also collected in FM-VP4 kinetics study to measure tissue distribution of radioactivity. Plasma [3H]-cholesterol and [3H]FM-VP4 were tested for radioactivity. RESULTS FM-VP4 co-administration significantly decreased [3H]-cholesterol AUC0-48h and Cmax, and increased CL/F and Vd/F of [3H]-cholesterol as compared to controls in a dose-dependent manner. Following oral administration of [3H]FM-VP4, the majority of radioactivity following was recovered in the feces and gastrointestinal (GI) tract. The compound exhibited an oral bioavailability of 6.5%. Following IV administration, a two-compartment pharmacokinetic model was observed and the majority of the radioactivity was recovered in the GI tract. CONCLUSIONS FM-VP4 reduces plasma concentration of [3H]-cholesterol in fasting rats. [3H]FM-VP4 has a very low oral bioavailability.