[Study on pharmacokinetics and in vitro/in vivo correlation of menthol in Zhike Chuanbei Pipa dropping pills in rats].

To determine the concentration of menthol in rat plasma by GC. Rats were administered with single dose of Zhike Chuanbei Pipa dropping pills (ZCPDP) and different doses of menthol herbs. DAS 3. 1.6 software was used to calculate pharmacokinetic parameters, and the accumulative absorption percentage of menthol was calculated by Loo-Riegelman method. The linear regression analysis was made in vitro/in vivo accumulative absorption percentages to detect the in vitro/in vivo correlation. The results of the study showed that the pharmacokinetics behavior of menthol in ZCPDP was in conformity with two-compartment model characteristics. The main parameters were: tmax was 10 min, t1/2beta was (183. 93 52. 75) min, CL/F was (0. 426 +/- 0. 194) L . min-1 . kg-1, all of which were no difference between ZCPDP and menthol herbs with the same dosage. There were significant differences in tmax, t1/2beta, CL/F between menthol herbs with different dosages (P <0. 05) , with indirect proportion between AUC0-infinity and dosage. The regression equation of ZCPDP's accumulative absorption percentage and accumulative release percentage was Fa = 1. 160 3Q - 19. 968, r = 0. 981 3. These results suggested that the pharmacokinetics behavior was similar between ZCPDP and menthol herbs with the same dosage in rats, with good in vitro/in vivo correlation. There were significant differences in pharmacokinetics of menthol in the range of 19.2-570 mg . kg-1.

[Absorption and distribution of extracts of Elsholtzia blanda in rats].

The study is aimed to establish a RP-HPLC method for determination of luteolin from the extracts of Elsholtzia blanda (EEB) in rats' biological specimen. A RP-HPLC method was established for determination of free and total luteolin in SD rats' plasma and gastrointestinal tract and total luteolin in SD rats' heart, liver, lung and kidney at 0.17, 0.5, 1, 2, 4 and 6 h after administration of EEB to 24 male SD rats (4 rats per one time spot). Luteolin glycoside was hydrolyzed to aglycone luteolin in intestinal tract, and then luteolin was absorbed. The main form of luteolin existed in gastrointestinal tract after administration of EEB is aglycone. The content of luteolin in liver and kidney were higher than that in heart and lung. The content of luteolin in kidney, heart and lung were showed max at 1 h. Its peak time was similar to that in blood. However, in liver, the drug was distributed quickly, and showed max at 0.17 h. And because of the sensitivity of the method, luteolin was not be detected in other tissues. The method is sensitive, specific, accurate, and is appropriate for determination of luteolin in vivo.

[Luteolin excretion after oral administration of Elsholtzia blanda benth extracts in rats].

OBJECTIVE: To observe the excretion of luteolin after oral administration of Elsholtzia blanda benth extracts in rats. METHODS: Samples of urine, feces and bile were collected after oral administration of Elsholtzia blanda benth extracts in rate. After deconjugation with beta-glucuronidase/sulfatase, the levels of luteolin in urine, feces and bile were measured by RP-HPLC. RESULT: The recovery rate of luteolin was 98.0 %-106.0 % and the extract recoveries were 85.0 %-108.0%. Relative standard deviation (RSD) of intra-and inter-day assay was less than 10.0 %. The total accumulative excretion was 37 % (11 % in urine, 26 % in feces and bile). CONCLUSION: The established RP-HPLC method is sensitive, specific, accurate, and is applicable for determination of luteolin in rat urine,feces and bile.