Biotransformation and pharmacokinetics of inositol hexanicotinate in rats

Xenobiotica. 2013 Sep;43(9):817-22. doi: 10.3109/00498254.2012.762591. Epub 2013 Jan 24.

Abstract

Inositol hexanicotinate (IHN) is an ester of the anti-hyperlipidemic drug nicotinic acid (NA). This study assessed the hydrolysis rate of IHN in human and rat plasma, and pharmacokinetics of the drug using a rat animal model. IHN (10 or 50 µg/mL) was incubated in plasma at 37 °C for 72 h. Kinetic parameters were determined based on the disappearance of IHN and the appearance of NA. The mean IHN disappearance and NA appearance half-lives were 1.07 and 3.93 h in human plasma, and 0.152 and 2.68 h in rat plasma. Increasing the initial plasma concentration to 50 µg/mL increased the NA appearance half-life in human and rat plasma to 4.66 and 6.47 h, respectively. After single 50 or 100 mg/kg intravenous dose of IHN to Sprague-Dawley rats, the drug showed statistically significant dose-dependent alterations in systemic clearance, suggesting a non-linear saturable elimination of IHN. Dose-normalized mean plasma levels of NA increased by 30% with increasing IHN dose (p < 0.02). The mean metabolic ratio (i.e. NA/IHN AUC ratio) significantly increased with increasing IHN dose (p < 0.05). The results provide first indication of saturable elimination and rapid disappearance of IHN, while niacin was slowly formed.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Biotransformation
  • Chromatography, High Pressure Liquid
  • Half-Life
  • Humans
  • Hydrolysis
  • Kinetics
  • Male
  • Nicotinic Acids / blood
  • Nicotinic Acids / chemistry
  • Nicotinic Acids / pharmacokinetics*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Nicotinic Acids
  • Inositol Niacinate