• The Journal of Korean Medicine
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• v.37 no.2
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• pp.1-11
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• 2016

Objectives: The objective of this study was to elucidate the effect of Jaeumkanghwatang (JEKHT) on the plasma concentration and pharmacokinetics of tamoxifen in combination therapy as a process of the comprehensive and integrative medicine against breast cancer. Methods: After 50 mg/kg of tamoxifen treatment, JEKHT 100 mg/kg was orally administered within 5 min. The plasma were collected at 30 min before administration, 30min, 1, 2, 3, 4, 6, 8 and 24 hrs after end of JEKHT treatment, and plasma concentrations of tamoxifen were analyzed using LC-MS/MS methods. PK parameters of tamoxifen ($T_{max}$, $C_{max}$, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with tamoxifen single administered rats. Results: JEKHT did not influenced on the plasma concentrations and pharmacokinetics of tamoxifen after single oral co-administration, within 5min except for some negligible effects on plasma concentration. The $T_{max}$, $C_{max}$, AUC, $t_{1/2}$ and $MRT_{inf}$ of tamoxifen in co-administered rats were quite similar to those of tamoxifen single treated rats. Conclusions: Based on the results of the present study, JEKHT did not influenced on the oral bioavailability of tamoxifen, when they were single co-administered within 5min. However, more detail pharmacokinetic studies should be tested to conclude the possibilities that can be used as comprehensive and integrative therapy with JEKHT and tamoxifen for breast cancers, when they were co-administered, like the effects on the pretreatment of JEKHT and after repeat co-administrations.

• Journal of Society of Preventive Korean Medicine
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• v.21 no.2
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• pp.127-137
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• 2017

Objectives : In our previous study, single co-administration GMODT within 5 min significantly inhibited the oral bioavailability of tamoxifen through variable influences on the absorption and excretion of tamoxifen. Therefore, the object of this study was to elucidate the possible effects on the pharmacokinetics of tamoxifen after single oral co-administration of GMODT with 2.5 hr-intervals. Methods : After 50 mg/kg of tamoxifen treatment, GMODT 100 mg/kg was administered with 2.5 hr-intervals. The plasma were collected at 30 min before administration, 30 min, 1, 2, 3, 4, 6, 8 and 24 hrs after end of GMODT treatment, and plasma concentrations of tamoxifen were analyzed using LC-MS/MS methods. PK parameters of tamoxifen (Tmax, Cmax, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with tamoxifen single administered rats. Results : Two-half hr-interval co-administration with GMODT induced variable changes on the plasma tamoxifen concentrations as compared with tamoxifen single treated rats, and especially significant (p<0.05) increases of plasma tamoxifen concentrations were demonstrated at 0.5 (199.61%) and 1 hr (101.06%) after end of co-administration with GMODT, and also related significant (p<0.05) decreases of $t_{1/2}$ (-39.54%) and $MRT_{inf}$ (-43.94%) as compared with tamoxifen single formula treated rats, at dosage levels of tamoxifen 50 mg/kg and GMODT 100 mg/kg with 2.5 hr-intervals, in this experiment. Conclusions : According to the results, GMODT critically decreased on the oral bioavailability of tamoxifen through variable influences on the absorption and excretion of tamoxifen. Hence, the co-administration of GMODT and tamoxifen should be avoided in the comprehensive and integrative medicine, combination therapy of tamoxifen with GMODT on the breast cancer.