Biomedical subjects

Miao-Ying Lai

Publications and source records attributed to Miao-Ying Lai.

3 recordsLinked to original sources

PubMed2004

Significant decrease of cyclosporine bioavailability in rats caused by a decoction of the roots of Scutellaria baicalensis.

Scutellariae Radix (SR), the root of Scutellaria baicalensis (Labiatae), is widely used in clinical Chinese medicine. In order to investigate the effect of SR on the absorption and disposition of cyclosporine, rats were administered with cyclosporine orally (in the form of the microemulsion Neoral and intravenously with and without coadministration of SR decoction in randomized cross-over designs, respectively. Furthermore, the effects of the major constituents, e. g., baicalin and its aglycone baicalein on cyclosporine pharmacokinetics were also investigated in rats. A specific monoclonal fluorescence polarization immunoassay was used to determine the blood concentration of cyclosporine. Our results indicated that coadministration of SR decoction at doses of 1 g/kg and 2 g/kg significantly decreased the C (max) of cyclosporine by 62.9 % and 79.6 % and reduced the AUC (0 - 540) by 55.2 % and 82.0 %, respectively. On the contrary, coadministration of baicalin and baicalein at doses of 112 micromol/kg markedly elevated the C (max) of cyclosporine by 408.1 % and 87.5 % and increased the AUC (0 - 540) by 685.3 % and 150.2 %, respectively. Nevertheless, SR decoction did not alter the pharmacokinetics of intravenous cyclosporine. These results indicate that a profound interaction between SR decoction and cyclosporine occurred at the absorption site. In order to ensure the efficacy and safety of cyclosporine, the coadministration of SR and its preparations with oral cyclosporine should be avoided.

Animals↗

PubMed2003

Comparison of metabolic pharmacokinetics of baicalin and baicalein in rats.

Baicalin and baicalein, a flavone glucuronide and its aglycone, are bioactive constituents of Scutellariae Radix with various beneficial activities. We have characterized and compared the metabolic pharmacokinetics of baicalin and baicalein in rats. Baicalein was administered intravenously and orally to rats, and baicalin was orally administered. An HPLC method was used to determine the concentration of baicalein before and after hydrolysis using beta-glucuronidase/sulfatase. The pharmacokinetic parameters were calculated by using WINNONLIN. Unpaired Student's t-test was used for statistical comparison. The result showed that after intravenous administration of baicalein, 75.7% of the dose was circulating as its conjugated metabolites. After oral administration of baicalein, absorption of baicalein itself was negligible, whereas the glucuronides/sulfates of baicalein were predominant in the plasma. When compared with intravenous bolus administration with dose correction, the absolute absorption was 40%. When baicalin was administered orally, glucuronides and sulfates of baicalein were exclusively circulating in the plasma. The relative absorption for baicalin was 65% when compared with baicalein. Profound differences of serum profile and pharmacokinetics were observed between oral baicalein and baicalin. Baicalin demonstrated significantly later time to peak concentration (t(max)) and lower peak serum concentration (C(max)) of baicalein conjugated metabolites than baicalein, indicating baicalin was absorbed more slowly and to a lesser extent than baicalein.

Absorption↗

PubMed2003

Urinary pharmacokinetics of baicalein, wogonin and their glycosides after oral administration of Scutellariae Radix in humans.

Baicalin, baicalein, wogonoside and wogonin are flavone constituents of Scutellariae Radix with various beneficial biological activities. The purpose of this study was to investigate the urinary pharmacokinetics of these flavones after oral administration of Scutellariae Radix commercial powder. Ten healthy male volunteers received a dose of 5.2 g commercial powder (comparable to 9 g crude drug), respectively. The concentrations of baicalin, baicalein and wogonin in the commercial powder as well as their metabolites in urine were assayed by HPLC method. The glucuronides and sulfates of baicalein and wogonin in urine were hydrolyzed with beta-glucuronidase and sulfatase, respectively. Our results showed that the mean cumulated renal excretion of baicalein glucuronides and sulfates were 43.1+/-4.5 micromol (2.9% of dose) and 64.8+/-6.3 micromol (4.3% of dose), respectively, whereas wogonin glucuronides and sulfates were 21.6+/-2.0 micromol (5.9% of dose) and 20.7+/-1.7 micromol (5.7% of dose), respectively. The result indicated that the renal excretion of conjugated metabolites of wogonin (11.6% of dose) were higher than that of baicalein (7.2% of dose). The baicalein sulfates was predominant than the corresponding glucuronides, whereas wogonin sulfates was comparable to the corresponding glucuronides.

Administration, Oral↗