Determination and Pharmacokinetics of Isoliquiritigenin in Rat Plasma by RP–LC After Intravenous Administration

Pharmacokinetics, biodistribution and bioavailability of isoliquiritigenin after intravenous and oral administration

CONTEXT

Isoliquiritigenin (ISL) has been shown to exhibit a variety of biological activities. However, there is little research on the pharmacokinetic behavior and tissues distribution of ISL.

OBJECTIVE

Pharmacokinetics, biodistribution and bioavailability of ISL after intravenous and oral administration were determined by systematic investigation in Sprague-Dawley rats.

MATERIALS AND METHODS

ISL was dissolved in medicinal ethanol-Tween 80-0.9% sodium chloride saline in a volume ratio of 10:15:75. The ISL solution was injected in rats via a tail vein at a single dose of 10, 20 and 50 mg/kg and administered orally in rats at a single dose of 20, 50 and 100 mg/kg, respectively. Blood samples were collected at time intervals of 0.08, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 6, 8 and 12 h after intravenous injection. Tissues of interests in mice were collected immediately at each determined time point (0.5, 1, 2, 3 and 6 h) after cervical dislocation.

RESULTS

The dose-normalized AUC values were 7.3, 7.6 and 8.7 μg × h/ml (calculated based on the dose of 10 mg/kg) for intravenous doses of 10, 20 and 50 mg/kg, respectively. The elimination half-lifes (t1/2λ) were 4.9, 4.6 and 4.8 h at 10, 20 and 50 mg/kg intravenous doses, respectively. The F values were 29.86, 22.70, 33.62% for oral doses of 20, 50 and 100 mg/kg, respectively. Liver, heart and kidney were major distribution tissues of ISL in mice. The plasma protein binding of ISL in rats was 43.72%.

CONCLUSION

The work may useful for further study of the bioactive mechanism of ISL.

Preparation of isoliquiritigenin-loaded nanostructured lipid carrier and the in vivo evaluation in tumor-bearing mice

Isoliquiritigenin-loaded nanostructured lipid carrier (ISL-NLC) was constructed and characterized. In vivo antitumor efficacy and immuno-modulation effects of ISL-NLC were evaluated in sarcoma 180 (S180)-bearing and murine hepatoma 22 (H22)-bearing mice model through intraperitoneal (i.p.) administration. The ISL-NLC biodistribution was also investigated in H22-bearing mice. Results demonstrated that the ISL-NLC had a spherical shape with a mean size of (160.73 ± 6.08) nm and encapsulation efficiency of (96.74 ± 1.81)%. ISL released from the nanoparticles was in a sustained manner with an initial burst release. ISL-NLC significantly inhibit tumor growth at 10, 20 and 40 mg/kg levels, and inhibition rates were 75.70%, 82.27% and 83.90% in the S180-bearing mice and 71.49%, 81.11% and 85.62% in the H22-bearing mice, respectively. The biodistribution study showed that ISL concentration of ISL-NLC in tumor is higher 2.5-fold than ISL suspension. The elimination half-life (t1/2), area under the curve (AUC) and the mean residence times (MRTs) of the ISL-NLC was much longer than that of the ISL suspension. As a whole, anticancer effect of ISL encapsulated in NLC was superior to ISL in suspension on H22-bearing and S180-bearing mice at the same dose and was a dose-dependent way, and ISL-NLC improved immunity of ISL. It can be inferred that nanostructured lipid carriers are a promising carrier for cancer therapy using ISL.

Pharmacokinetics and tissue distribution of 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside from traditional Chinese medicine Polygonum multiflorum following oral administration to rats

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum multiflorum is an important traditional Chinese medicine used for health promotion and disease treatment. One major bioactive compound in P. multiflorum is a stilbene glycoside (2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside, PM-SG), which possesses antioxidative, anti-inflammatory and endothelial-protective activities.

MATERIALS AND METHODS

The purpose of the present study was to investigate in vivo pharmacokinetics and tissue distribution of PM-SG after oral administration of Polygonum multiflorum extract to rats by using a reversed-phase high-performance liquid chromatography coupled with liquid-liquid phase extraction. The pharmacokinetic parameters were determined using both compartmental and non-compartmental analyses.

RESULTS

All calibration curves for PM-SG in rat plasma and tissues were linear (all r(2)>0.99) over the range of 0.27-185.00 μg/ml. The intra- and inter-day variations were less than 3% at concentration range of 8.7-131.2 μg/ml and good overall recoveries (97.7-101.5%) were obtained at the same range. The maximum concentration (C(max)) and the time to reach this concentration (T(max)) of PM-SG were 31.9 μg/ml and 40.0 min, respectively. The pharmacokinetic profiles estimated by fitting two-compartment and non-compartment models revealed that PM-SG was rapidly absorbed into the body fluids and widely distributed throughout the body, with great efficiency of utility, followed by quick elimination. The highest PM-SG levels were detected in liver and lungs (90.3 ± 20.8 μg/g and 86.8 ± 9.0 μg/g, respectively) whereas little in brain and testes, indicating PM-SG can hardly penetrate the blood-brain and blood-testicle barriers.

CONCLUSIONS

This was the first report on the favorable pharmacokinetic profiles of PM-SG in rat plasma and tissues after oral administration. It may provide a meaningful basis for clinical application of such a bioactive compound of herbal medicines.