Pharmacokinetic interaction of Forsythia suspensa extract and azithromycin injection after single and co-intravenous administration in rats

Azithromycin and Chinese medicine forsythia are often used together to treat pediatric mycoplasma infections in China. We aimed to investigate the pharmacokinetic interaction of Forsythia suspensa extract and azithromycin after single and co-intravenous administration in rats. Male Sprague-Dawley rats received single(Forsythia suspensa extract or azithromycin) treatment or co-administration of Forsythia suspensa extract and azithromycin. Blood samples were collected at scheduled times, and drug concentrations were determined by HPLC-UV or HPLC-MS/MS methods. Both non-compartmental analyses and nonlinear mixed-effects modeling approaches were applied to fit pharmacokinetic data and evaluate the impact of co-administration. Pharmacokinetic analysis showed that the area under the curve of azithromycin and forsythiaside increased, and clearance decreased significantly(P < 0.05),after co-administration. The in vivo behavior of both azithromycin and forsythiaside could be appropriately described by the two-compartmental model. The final population pharmacokinetic model indicated that co-administration decreased the central volume of azithromycin and forsythiaside clearance significantly. Co-administration of Forsythia suspensa extract and azithromycin significantly decreased the clearance and increased exposure for both drugs. Pharmacokinetic data suggest that drug co-administration may increase efficiency.

Pharmacokinetic study of gallocatechin-7-gallate from Pithecellobium clypearia Benth. in rats

The pharmacokinetic profile of gallocatechin-7-gallate(J10688)was studied in rats after intravenous administration.Male and female Sprague-Dawley(SD)rats received 1,3,and 10 mg/kg(i.v.)of J10688 and plasma drug concentrations were determined by a high performance liquid chromatography-mass spectrometry(LC–MS)method.The pharmacokinetic software Data Analysis System(Version 3.0)was used to calculate the pharmacokinetic parameters.For different i.v.doses of J10688,the mean peak plasma concentration(C_0)values ranged from 11.26 to 50.82 mg/L,and mean area under the concentration-time curve(AUC_(0–t))values ranged from 1.75 to 11.80(mg h/L).J10688 lacked dosedependent pharmacokinetic properties within doses between 1 and 10 mg/kg,based on the power model.The method developed in this study was sensitive,precise,and stable.The pharmacokinetic properties of J10688 in SD rats were shown to have rapid distribution and clearance values.These pharmacokinetic results may contribute to an improved understanding of the pharmacological actions of J10688.