Multiple circulating alkaloids and saponins from intravenous Kang-Ai injection inhibit human cytochrome P450 and UDP-glucuronosyltransferase isozymes: potential drug–drug interactions

Abstract

Background Kang-Ai injection is widely used as an adjuvant therapy drug for many cancers, leukopenia, and chronic hepatitis B. Circulating alkaloids and saponins are believed to be responsible for therapeutic effects. However, their pharmacokinetics (PK) and excretion in vivo and the risk of drug–drug interactions (DDI) through inhibiting human cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes remain unclear. Methods PK and excretion of circulating compounds were investigated in rats using a validated ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC–MS) method. Further, the inhibitory effects of nine major compounds against eleven CYP and UGT isozymes were assayed using well-accepted specific substrate for each enzyme. Results After dosing, 9 alkaloids were found with Cmax and t1/2 values of 0.17–422.70 μmol/L and 1.78–4.33 h, respectively. Additionally, 28 saponins exhibited considerable systemic exposure with t1/2 values of 0.63–7.22 h, whereas other trace saponins could be negligible or undetected. Besides, over 90% of alkaloids were excreted through hepatobiliary and renal excretion. Likewise, astragalosides and protopanaxatriol (PPT) type ginsenosides also involved in hepatobiliary and/or renal excretion. Protopanaxadiol (PPD) type ginsenosides were mainly excreted to urine. Furthermore, PPD-type ginsenosides were extensively bound (fu-plasma approximately 1%), whereas astragalosides and PPT-type ginsenosides displayed fu-plasma values of 12.35% and 60.23–87.36%, respectively. Moreover, matrine, oxymatrine, astragaloside IV, ginsenoside Rg1, ginsenoside Re, ginsenoside Rd, ginsenoside Rc, and ginsenoside Rb1 exhibited no inhibition or weak inhibition against several common CYP and UGT enzymes IC50 values between 8.81 and 92.21 μM. Through kinetic modeling, their inhibition mechanisms towards those CYP and UGT isozymes were explored with obtained Ki values. In vitro-in vivo extrapolation showed the inhibition of systemic clearance for CYP or UGT substrates seemed impossible due to [I]/Ki no more than 0.1. Conclusions We summarized the PK behaviors, excretion characteristics and protein binding rates of circulating alkaloids, astragalosides and ginsenosides after intravenous Kang-Ai injection. Furthermore, weak inhibition or no inhibition towards these CYP and UGT activities could not trigger harmful DDI when Kang-Ai injection is co-administered with clinical drugs primarily cleared by these CYP or UGT isozymes.

Potential metabolism determinants and drug–drug interactions of a natural flavanone bavachinin

“…As published previously, phenacetin (100 mM), bupropion (100 mM), paclitaxel (60 mM), tolbutamide (200 mM), mephenytoin (100 mM), chlorzoxazone (200 mM) and nifedipine (40 mM) have been well-accepted as the specic substrates for CYP1A2, 2B6, 2C8, 2C9, 2C19, 2E1, and 3A4, respectively. 27,30 Similarly, b-estradiol (60 mM), propofol (40 mM) and zidovudine (500 mM) were typically used as the selective probe substrates for UGT1A1, 1A9, and 2B7, respectively. 31,32 The substrates above were separately incubated with CYP isozyme (or UGT enzymes) in the absence (control) and presence of bavachinin (1, 10, 100 mM) at optimized incubation time and protein concentration as described previously.…”

“…31,32 The substrates above were separately incubated with CYP isozyme (or UGT enzymes) in the absence (control) and presence of bavachinin (1, 10, 100 mM) at optimized incubation time and protein concentration as described previously. 27,[30][31][32] The half-inhibition concentration (IC 50 ) values of bavachinin towards individual CYP and UGT isozyme were obtained using the non-linear regression analysis. Traditionally, the inhibitory effects could be divided into four categories based on the IC 50 values as follows: potent (less than 1 mM), moderate (between 1 and 10 mM), weak (over 10 mM), or no inhibition (over 100 mM).…”

“…Moreover, drug-drug interactions (DDI) are involved in clinical rational drug use, and are signicant clinical safety concerns. [26][27][28] Human CYP1A2 (9%), 2B6 (2%), 2C8, 2C9 (16%), 2C19 (12%), 2E1 (2%), 3A4 (46%), and UGT1A1 (15%), 1A9, 2B7 (35%) participated most in the metabolism or elimination of clinical drugs. 29,30 Once the function of these CYP (or UGT) isozymes were inhibited (or induced) by bavachinin, the exposure (represented by AUC 0-t values) of co-administrated drugs could be markedly increased (or decreased), which further brought several adverse reactions (or insufficient efficacy).…”

“…A great deal of effort is needed to avoid in new drug of active ingredient research in avoiding the development of the active composition of natural medicine that will cause drug-drug interactions in clinical application. [26][27][28] On the other hand, co-administration of herbal medicines is now a common therapeutic practice in patients with multiple complications and interactions are not avoidable. 27 Thus, adequate preclinical studies are necessary for further clinical treatment.…”

“…[26][27][28] On the other hand, co-administration of herbal medicines is now a common therapeutic practice in patients with multiple complications and interactions are not avoidable. 27 Thus, adequate preclinical studies are necessary for further clinical treatment.…”