Disposition of the Flavonoid Quercetin in Rats After Single Intravenous and Oral Doses

Abstract

The pharmacokinetic and mean time tissue distribution parameters, after a single 50-mg/kg dose of quercetin administered as intravenous bolus, oral solution, and oral suspension, were determined using rat as an animal model. Following intravenous administration, the elimination rate constant and the elimination half-life were found to be 0.0062 min(-1) and 111 min, respectively. Examining the mean time tissue distribution parameters reflected a strong binding affinity of the drug molecules to both plasma and tissue proteins. In addition, the low permeability rate of drug molecules in the peripheral system was demonstrated. Following the oral administration of the drug, the extent of absorption was greater from solution than from suspension. Moreover, the solution showed a shorter Tmax and a higher Cmax than suspension. The absolute bioavailability for the solution was 0.275 and that for suspension was 0.162. The mean residence time (MRT) and the mean absorption time (MAT) were higher for suspension, reflecting the need for dissolving the drug in order to be absorbed. The mean (in-vivo) dissolution time (MDT(in-vivo)) was 34.5 min. Thus, an oral quercetin formulation that can readily form a drug solution in the gastrointestinal tract may enhance the absorption of the drug.

Quercetin in an animal model of spinal cord compression injury: correlation of treatment duration with recovery of motor function

“…1 Using a dose of 100 mmoles kg À1 twice daily, one would anticipate that plasma quercetin levels would peak at higher levels than when a dose of 25 mmoles kg À1 was administered thrice daily. It is known that quercetin, in solution administered intravenously in the rat, has a biphasic plasma clearance with a rapid drop in concentration followed by a slower drop with a half-life of 111 min with an intrinsic mean residence time within peripheral tissues of just over 3 h. 14 In our investigations, quercetin is administered intraperitoneally in the form of a suspension in saline. The work of Khaled and colleagues 14 has demonstrated that quercetin administered as a suspension takes 50% longer time to enter plasma than quercetin administered in solution; hence, one might anticipate a longer quercetin residence time in tissues that may affect therapeutic efficacy.…”

Enzymatically Modified Isoquercitrin, .ALPHA.-Oligoglucosyl Quercetin 3-O-Glucoside, Is Absorbed More Easily than Other Quercetin Glycosides or Aglycone after Oral Administration in Rats

“…19) In our preliminary experiment, the bioavailability of quercetin dissolved in dimethylsulfoxide/water (70 : 30) solution in rats was 3.2-fold higher than that of quercetin suspended in water. Thus, the solubility of quercetin is a highly important factor for its bioavailability.…”

Production of stabilized quercetin aqueous suspensions by supercritical fluid extraction of emulsions

“…Due to the low water solubility of quercetin, it has a minimal absorption in the gastrointestinal tract, and its oral bioavailability is lower than 17% in rats [6] and lower than 1% in humans [7]. Different approaches have been proposed in literature to increase the bioavailability of quercetin.…”