Effects of mixed formulation of tamoxifen and blue honeysuckle on the pharmacokinetics profiles of tamoxifen after single oral administration

Objectives: Here, we investigated the effects of concentrated and lyophilized powders Blue honeysuckle (BH) on the PK of tamoxifen, to establish the pharmacokinetics (PK) profiles as one of essential process in new drug development. Methods: After single oral treatment of 0.4 mg/ml of tamoxifen or tamoxifen 0.4 with BH 40, 20 and 10 mg/ml, the plasma were collected at 0.5 hr before administration, 0.5, 1, 2, 3, 4, 6, 8 and 24 hr after end of single or mixed formula treatment. Plasma concentrations of tamoxifen were analyzed using LC-MS/MS methods. Tmax, Cmax, AUC, t1/2 and MRTinf were analyzed using noncompartmental PK data analyzer programs. Results: Tamoxifen and BH 40 mg/ml did not induce any significant change on the plasma tamoxifen concentrations, while significant decreases were observed in tamoxifen and BH 10 mg/ml from 2 to 8 hr as compared with tamoxifen only, respectively. Furthermore, significant increases of Tmax in tamoxifen and BH 40 mg/ml, significant decreases of Cmax in tamoxifen and BH 20 mg/ml, significant decreases of AUC0-t, AUC0-inf and MRTinf in tamoxifen and BH 10 mg/ml were demonstrated as compared with tamoxifen only. Conclusion: Taken together, tamoxifen and BH 10 mg/ml induced significant decrease of the oral bioavailability of tamoxifen, while tamoxifen and BH 40 or 20 mg/ml did not critically influenced, suggesting formulated BH concentration-independencies. It, therefore, seems to be needed that pharmacokinetic study after repeated administration should be tested to conclude the effects of BH on the pharmacokinetics of tamoxifen.