OBJECTIVETo study the pharmacokinetics of matrine (MT) intramuscular administration in rat.

METHODPlasma concentration of matrine was determined by HPLC under the following conditions: column (Shim-pack VP-ODS, 4. 6 mm x 150 mm, 5 m); eluent (acetonitrile-0.02 mol ammonium acetate buffer-triethylamine 30: 70: 0.04); flow rate was 1 mL x min(-1) and ultraviolet detection wavelength was set at 220 nm; column temperature 40 degrees C; aliquot injected 20 microL. All data of concentration-time of matrine were treated with pharmacokinetics program DAS 2. 1. 1.

RESULTA simple, sensitive and reliable method for determining matrine in rat plasma by HPLC was established. The plasma concentration time profiles of MT fitted in with two-compartment models well, and the main pharmacokinetic parameters found for MT after i. m. infusion were as follows: C(max) = 21.113 9 mg x L(-1), t(max) = 0.75 h, t1/2alpha 1.34 h, t1/2beta = 3.509 h, AUC(0-t) = 90.984 mg x h(-1) x L(-1), AUC(0-infinity) = 100.346 mg x h(-1) x L(-1).

CONCLUSIONCompare with oral administration, the matrine is absorbed well and distributes fast with intramuscular administration; the absolute bioavailability of matrine is higher. According to this, the pharmacological action is also stronger and duration is longer.