A clinical evaluation to determine the safety, pharmacokinetics, and pharmacodynamics of an inositol-stabilized arginine silicate dietary supplement in healthy adult males

Douglas S Kalman, Samantha Feldman, Adam Samson, Diane R Krieger Miami Research Associates, Miami, FL, USA Purpose: The purpose of this study was to characterize the pharmacokinetics (PKs) and pharmacodynamics (PDs) of an oral inositol-stabilized arginine silicate dietary supplement. Subjects and methods: Ten healthy males, 26.7±5.4 years, took three 500 mg arginine silicate capsules (active product) for 14 days. The subjects attended test visits on Days 1 and 14. Fasting blood and saliva collections were performed predose and at 0.5 hours, 1 hour, 1.5 hours, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours postdose for plasma arginine, serum silicon, and salivary nitric oxide (NO) + nitrite. Results: Day 1 PK parameters (adjusted for body weight) for arginine were peak serum concentration (CMax) 30.06±7.80 µg/mL, time it takes to reach peak serum concentration (tMax) 1.13±0.52 hours, and time required to reach half its original concentration (t1/2) 15.93±9.55 hours and for silicon were CMax 2.99±0.63 µg/mL, tMax 2.44±2.05 hours, and t1/2 34.56±16.56 hours. After Day 1 dose, arginine levels increased at 0.5 hours, 1 hour, 1.5 hours, 2 hours, 3 hours, and 5 hours (P