Effect Of Bicyclol On Pharmacokinetics Of Rifampin And Isoniazid In Rats

Objectives:To establish reverse phase high-performance liquid chromatography methods to determine the plasma concentration of Rifampin and Isoniazid in rat respectively,and observe the effects of Bicyclol on the pharmacokinetics parameters of Rifampin and Isoniazid in rats.Methods:1.The concentration of Rifampin in plasma was detected by reverse phase high performance liquid chromatography.After Serum protein was precipitated with methanol and filtrated with 0.22μm membrane,the sample were injected and analysized.Chromatographic column:Shim-pack VP-ODS(5μm,250mm×4.6mm); Mobile phase:methanol and water(70:30,â…¤:â…¤);Flow rate:1.0ml.min^-1;Ultraviolet wave lengh:336nm.The concentration of isoniazid in plasma was detected by reverse phase high performance liquid chromatography.The plasma sample was injected directly for determination after being deproteinized with 10%trichloroacetic acid and reacted with cinnamaldehyde.Chromatographic column:Shim-packVP-ODS (5μm,250mm×4.6mm);Mobile phase:KH₂PO₄ and acetonitrile(48:52,â…¤:â…¤);Flow rate:1.0ml.min-1;Ultraviolet wave lengh:340nm.2.Thirty-six rats were divided randomly into six groups:rifampin group(â… ),isoniazid group(â…¡),bicyclol+ rifampin group(â…¢),bicyclol+isoniazid group(â…£),rifampin + isoniazid group(â…¤),bicyclol +rifampin + isoniazid group(â…¥).Drug dosage:bicyclol was 15.85 mg.kg^-1,rifampin was 63.4 mg.kg^-1,isoniazid was 31.7 mg.kg^-1,once every day for 4 days. Plasma samples were obtained on day 4 at 0,0.25,0.5,1,1.5,2,4,6,8,12,24h after administration.Concentrations of rifampin and isoniazid were determined by reverse phase high-performance liquid chromatography.Pharmacokinefics parameters were evaluated by DAS2.0 pharmacokinetics pragramme.Parameters were analyzed by SPSS(11.5)software.Results:The linear relation of rifampin was excellent within the range of 1.25-80.0 ug.ml^-1(R²=0.9995),and the mean recovery was 101.54%Daily and daytime RSD were less than 5%.The linear relation of isoniazid was excellent within the range of 0.25-32.0 ug.ml^-1(R²=0.9996),and the mean recovery was 98.64%.Daily and daytime RSD were less than 5%.There groups that respectively used bicyclol in combination with rifampin,or with isoniazid,or with both rifampin and isoniazid, were considered.In each time points,there was no significant difference(P＞0.05) among the drug concentrations in blood of the other groups.Only in time point of six hours,the drug concentration in blood of the three drug combination group differed from the control group(P＜0.05).Pharmacokinetic parameters,included AUC_(0-t),AUC_(0-∞),MRT_(0-t),MRT_(0-∞),t_1/2z,T_max,CL_z/F,V_z/Fand C_max,were found no significant difference(P＞0.05)among the groups.Conclusion:1.The methods of determination of isoniazid and rifampicin concentration are established,and they are simple,rapid,accurate,reproducible and suitable for the determination of biological samples.2.Bicyclol has no effects on the pharmacokinetic parameters of rifampin or/and isoniazid,when it combinates with two major anti-tuberculosis drugs.That means bicyclol may combine with rifampin and isoniazid in clinical therapy.It is no need to adjust dose and regimen of rifampin or isoniazid.