Pharmacokinetics and Salivary Distribution of Baicalin in Shuanghuanglian at Different Doses Administration

OBJECTIVE To identify pharmacokinetics and salivary distribution of baicalin after different doses administration of Shuanghuanglian injection to rats.METHODSEach rat was given a dose of Shuanghuanglian injection via the vein.An RP-HPLC method was used to determine the concentrations of baicalin in plasma and saliva.Pharmacokinetic model and parameters were analyzed by pharmacokinetics program MULTI97V10.RESULTSBaicalin showed two compartment model after administration of Shuanghuanglian at high,medium and low-dose(740,555,370 mg·kg-1) and the main parameters of pharmacokinetics in each dose were as follows:t1/2=(0.79±0.12)h,AUC=(1.30±0.13)mg·h·mL-1,Vc=(0.21±0.036)L,CL=(0.19±0.019)L·h-1;t1/2=(1.52±0.14)h,AUC=(1.22±0.20)mg·h·mL-1,Vc=(0.36±0.04)L,CL=(0.16±0.030)L·h-1;t1/2=(0.34±0.021)h,AUC=(0.22±0.004)mg·h·mL-1,Vc=(0.33±0.027)L,CL=(0.66±0.014)L·h-1.The salivary level of baicalin in high-dose was within 0.11-0.78 μg·mL-1.CONCLUSIONBecause AUC of baicalin was not increased proportionally with the doses of Shuanghuanglian,it was suggested that baicalin would present nonlinear pharmacokinetics.Baicalin was excreted into saliva much more lowly than blood.