Comparative pharmacokinetics of arctigenin in normal and type 2 diabetic rats after oral and intravenous administration

Simultaneous Determination of Telmisartan and Pitavastatin Calcium in Intestinal Perfusate by HPLC: Application to Intestinal Absorption Interaction Study

BACKGROUND

Hypertension and hypercholesterolemia are two main physiological risk factors of cardiovascular disease, and commonly occur in combination. Multicompound combination therapy is rational for the treatment of concurrent hypertension and hypercholesterolemia, while telmisartan and pitavastatin calcium can be used as a potential drug combination.

OBJECTIVE

The aim of this paper is to study the intestinal absorption and absorption interaction of telmisartan and pitavastatin calcium.

METHODS

An HPLC method was developed and validated to determine telmisartan and pitavastatin calcium in intestinal perfusate simultaneously. The in situ single-pass perfusion in rats was utilized to investigate the effects of concentrations, intestinal segment (duodenum, jejunum, ileum and colon) and co-administrated drugs on absorption.

RESULTS

The effective permeability coefficient and the absorption rate constant of telmisartan were higher in the duodenum as compared to other intestinal segments. However, the intestinal absorption of pitavastatin calcium was not segmental dependent. The effective permeability coefficient and absorption rate constant have no significant difference among three concentrations of telmisartan, pitavastatin calcium individually and their combination.

CONCLUSION

The results showed that telmisartan and pitavastatin calcium were transported passively, and telmisartan and pitavastatin calcium could be absorbed well in all intestinal segments. The intestinal absorption parameters revealed the absence of any intestinal absorption interaction when co-administered. Lay Summary: Co-administration of telmisartan and pitavastatin calcium can provide a potential therapeutic strategy for the treatment of concurrent hypertension and hypercholesterolemia. We are investigating the intestinal interaction of these two drugs in rats using the developed HPLC method and in situ single-pass perfusion technology. We will calculate some parameters after administrating two types of drugs either separately or together, which help reflect changes regarding intestinal absorption and penetration. Compared with telmisartan and pitavastatin calcium administrated separately, if parameters significantly change after co-administration, it proves the existence of the intestinal interactions. Moreover, the results might contribute to clinic drug monitoring.

Imbalance of Drug Transporter-CYP450s Interplay by Diabetes and Its Clinical Significance

The pharmacokinetics of a drug is dependent upon the coordinate work of influx transporters, enzymes and efflux transporters (i.e., transporter-enzyme interplay). The transporter-enzyme interplay may occur in liver, kidney and intestine. The influx transporters involving drug transport are organic anion transporting polypeptides (OATPs), peptide transporters (PepTs), organic anion transporters (OATs), monocarboxylate transporters (MCTs) and organic cation transporters (OCTs). The efflux transporters are P-glycoprotein (P-gp), multidrug/toxin extrusions (MATEs), multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). The enzymes related to drug metabolism are mainly cytochrome P450 enzymes (CYP450s) and UDP-glucuronosyltransferases (UGTs). Accumulating evidence has demonstrated that diabetes alters the expression and functions of CYP450s and transporters in a different manner, disordering the transporter-enzyme interplay, in turn affecting the pharmacokinetics of some drugs. We aimed to focus on (1) the imbalance of transporter-CYP450 interplay in the liver, intestine and kidney due to altered expressions of influx transporters (OATPs, OCTs, OATs, PepTs and MCT6), efflux transporters (P-gp, BCRP and MRP2) and CYP450s (CYP3As, CYP1A2, CYP2E1 and CYP2Cs) under diabetic status; (2) the net contributions of these alterations in the expression and functions of transporters and CYP450s to drug disposition, therapeutic efficacy and drug toxicity; (3) application of a physiologically-based pharmacokinetic model in transporter-enzyme interplay.

Short-chain fatty acids oppositely altered expressions and functions of intestinal cytochrome P4503A and P-glycoprotein and affected pharmacokinetics of verapamil following oral administration to rats

OBJECTIVES

To investigate effects of short-chain fatty acids (SCFAs) on expressions and functions of intestinal cytochrome P4503A (Cyp3a) and P-glycoprotein (P-gp). To develop a semi-physiologically based pharmacokinetic (semi-PBPK) model for assessing their contributions.

METHODS

Verapamil pharmacokinetics was investigated following oral administration to rats receiving water containing 150 mm SCFAs for 3 weeks. Cyp3a activities in intestinal and liver mircosomes were assessed by norverapamil formation. In-situ single-pass perfusion was used to evaluate intestinal transport of verapamil and P-gp function. Functions and expressions of Cyp3a and P-gp were measured in mouse primary enterocytes following 48-h exposure to SCFAs. Contributions of intestinal P-gp and Cyp3a to verapamil pharmacokinetics were assessed using a semi-PBPK model.

KEY FINDINGS

Short-chain fatty acids significantly increased oral plasma exposures of verapamil and norverapamil. SCFAs upregulated Cyp3a activity and expression, but downregulated P-gp function and expression in rat intestine, which were repeated in mouse primary enterocytes. PBPK simulation demonstrated contribution of intestinal Cyp3a to oral plasma verapamil exposure was minor, and the increased oral plasma verapamil exposure was mainly attributed to downregulation of intestinal P-gp.

CONCLUSIONS

Short-chain fatty acids oppositely regulated functions and expressions of intestinal Cyp3a and P-gp. The downregulation of P-gp mainly contributed to the increased oral plasma verapamil exposure by SCFAs.

3'-Desmethylarctigenin induces G2/M cell cycle arrest and apoptosis through reactive oxygen species generation in hepatocarcinoma cells

Previous studies have shown that arctigenin is a promising chemopreventive or therapeutic agent against various cancers. However, less is known about anticancer activity of 3'-desmethylarctigenin (3'-DMAG), which is a biotransformed product from arctigenin or arctin. In this study, we compared the anticancer activity of 3'-DMAG with its parent compound arctigenin and demonstrated that 3'-DMAG exerted a more potent inhibitory effect on HepG2 cells than arctigenin. Mechanistically, reactive oxygen species generation played an apical role in 3'-DMAG-induced G2/M cell cycle arrest and apoptosis in HepG2 cells. Furthermore, the Chk2-Cdc25c-Cdc2-cyclin B1 cascade was found to contribute to the cell cycle arrest, whereas the activation of mitochondrial pathway was involved in the cell apoptosis by 3'-DMAG. Additionally, a mouse xenograft hepatocellular carcinoma model was used to evaluate the antitumor effect of 3'-DMAG in vivo, and the results indicated that 3'-DMAG treatment significantly inhibited tumor growth without apparent toxicity. Taken together, 3'-DMAG is highly effective against liver cancer both in vitro and in vivo. The findings of the present study suggest that this compound deserves to be further investigated for its potential anticancer activity.

Pharmacokinetics of Arctigenin and Fructus Arctii Powder in Piglets

Fructus arctii, also known as great power seed, is the dried fruit of Arctium lappa of the family Compositae. It is a commonly used veterinary herbal medicine, and arctigenin is the main active ingredient. The aim of this study was to characterize the absorption, distribution, metabolism, and excretion of arctigenin and Fructus arctii powder in piglets. These data were used to provide a theoretical reference for the development and clinical use of new veterinary drugs. Sixteen healthy piglets (mean weight 30.0 ± 5.0 kg) were divided into two groups. One group was administered 2.0 mg/kg body weight (bw) arctigenin intravenously, and the other was administered 1.0 g/kg^.bw Fructus arctii powder by gavage. Blood samples were collected from the anterior vena cava at different time points, and the concentration of arctigenin in the plasma of the piglets was determined using high-performance liquid chromatography (HPLC). Arctigenin conformed to a two-compartment model with no absorption, and the main pharmacokinetic parameters were as follows: distribution half-life (t_1/2α)−0.166 ± 0.022 h; elimination half-life (t_1/2β)−3.161 ± 0.296 h; apparent volume of distribution (V_d)−0.231 ± 0.033 L/kg; clearance rate (CL_b)−0.057 ± 0.003 L/(h.kg); and area under the curve (AUC)−1.189 ± 0.057 g^.h/mL. The pharmacokinetic parameters of arctigenin following oral administration of the Fructus arctii powder were as follows: absorption half-life (t_1/2ka)−0.274 ± 0.102 h, t_1/2α−1.435 ± 0.725 h, t_1/2β−63.467 ± 29.115 h, V_d−1.680 ± 0.402 L/kg, CL_b−0.076 ± 0.028 L/(h kg), peak time (t_max)−0.853 ± 0.211 h, peak concentration (C_max)−0.430 ± 0.035 g/mL, and AUC−14.672 ± 4.813 g/mL. These results indicated that intravenous arctigenin was sparingly distributed in tissues. In contrast, orally administered Fructus arctii powder was rapidly absorbed, more widely distributed, and more slowly eliminated than the intravenous arctigenin, which may indicate its sustained pharmacological effects.

Overview of the anti-inflammatory effects, pharmacokinetic properties and clinical efficacies of arctigenin and arctiin from Arctium lappa L

Arctigenin (AR) and its glycoside, arctiin, are two major active ingredients of Arctium lappa L (A lappa), a popular medicinal herb and health supplement frequently used in Asia. In the past several decades, bioactive components from A lappa have attracted the attention of researchers due to their promising therapeutic effects. In the current article, we aimed to provide an overview of the pharmacology of AR and arctiin, focusing on their anti-inflammatory effects, pharmacokinetics properties and clinical efficacies. Compared to acrtiin, AR was reported as the most potent bioactive component of A lappa in the majority of studies. AR exhibits potent anti-inflammatory activities by inhibiting inducible nitric oxide synthase (iNOS) via modulation of several cytokines. Due to its potent anti-inflammatory effects, AR may serve as a potential therapeutic compound against both acute inflammation and various chronic diseases. However, pharmacokinetic studies demonstrated the extensive glucuronidation and hydrolysis of AR in liver, intestine and plasma, which might hinder its in vivo and clinical efficacy after oral administration. Based on the reviewed pharmacological and pharmacokinetic characteristics of AR, further pharmacokinetic and pharmacodynamic studies of AR via alternative administration routes are suggested to promote its ability to serve as a therapeutic agent as well as an ideal bioactive marker for A lappa.

Experimental study of the anti-tumour activity and pharmacokinetics of arctigenin and its valine ester derivative

Arctigenin (ARG) is a functional active component that has important physiological and pharmacological activities. The anti-tumour and anti-inflammatory activities of ARG show good potential for application and development, but this material has the defect of low water solubility. In this experiment, the valine derivative of ARG (ARG-V) was designed and synthesized to overcome this disadvantage. The ARG amino acid, EDCI and DMAP were raw materials in the addition reaction, with a molar ratio of 1:2:2:0.5. The yield of ARG-V was up to 80%. ARG-V has strong anti-tumour activity in vivo and in vitro. The inhibitory rate of ARG-V was 69.2%, with less damage to the immune organs and different degrees of increased serum cytotoxicity. Moreover, the pharmacokinetics of ARG following oral administration and ARG-V following oral administration in rats were also studied. The C_max and AUC values of ARG-V showed significant differences compared to ARG. The relative bioavailabilities of three doses of ARG-V compared to ARG were 664.7%, 741.5% and 812.9%. These pharmacokinetic results may be useful for further studies of the bioactive mechanism of ARG and provide a theoretical basic for clinical use.

Comparative pharmacokinetics of four active components on normal and diabetic rats after oral administration of Gandi capsules

The Gandi capsule, a famous traditional Chinese medicine (TCM), is a hospital preparation that has been widely used in China for decades for the treatment of diabetes.

San-Huang-Xie-Xin-Tang Constituents Exert Drug-Drug Interaction of Mutual Reinforcement at Both Pharmacodynamics and Pharmacokinetic Level: A Review

Inflammatory disorders underlie varieties of human diseases. San-Huang-Xie-xin-Tang (SHXXT), composed with Rhizoma Rhei (Rheum palmatum L.), Rhizoma Coptidis (Coptis chinensis Franch), and Radix Scutellaria (Scutellaria baicalensis Georgi), is a famous formula which has been widely used in the fight against inflammatory abnormalities. Mutual reinforcement is one of the basic theories of traditional Chinese medicine. Here this article reviewed and analyzed the recent research on (1) How the main constituents of SHXXT impact on inflammation-associated signaling pathway molecules. (2) The interaction between the main constituents and efflux pumps or intestinal transporters. The goal of this work was to, (1) Provide evidence to support the theory of mutual reinforcement. (2) Clarify the key targets of SHXXT and suggest which targets need further investigation. (3) Give advice for the clinical use of SHXXT to elevated the absorption of main constituents and eventually promote oral bioavailability. We search literatures in scientific databases with key words of “each main SHXXT constituent,” in combination with “each main inflammatory pathway target molecule” or each main intestinal transporter, respectively. We report the effect of five main constituents on target molecules which lies in three main inflammatory signaling pathways, we as well investigate the interaction between constituents and intestinal transporter. We conclude, (1) The synergistic effect of constituents at both levels confirm the mutual reinforcement theory of TCM as it is proven in this work. (2) The effect of main constituents on downstream targets in nuclear need more further investigation. (3) Drug elevating the absorption of rhein, berberine and baicalein can be employed to promote oral bioavailability of SHXXT.

Effect of age on the pharmacokinetics of polymorphic nimodipine in rats after oral administration

The previous investigation has proved that their existed pharmacokinetic difference between the different crystal forms of the polymorphic drugs after oral administration. However, no systemic investigations have been made on the change of this pharmacokinetic difference, resulted either from the physiological or from the pathological factors. In this paper, we used polymorphic nimodipine (Nim) as a model drug and investigated the effect of age difference (2- and 9-month old) on the pharmacokinetics after oral delivery in rats. As the results shown, for L-form of Nim (L-Nim), the AUC_0-24 h in 2-month-old rats was 343.68±47.15 ng·h/mL, which is 23.36% higher than that in 9-month-old rats. For H-form of Nim (H-Nim), the AUC_0-24 h in 2-month-old rats was 140.91±19.47 ng·h/mL, which is 54.64% higher than that in 9-month-old rats. The AUC_0-24 h ratio between H-Nim and L-Nim was 2.44 in 2-month-old rats and 3.06 in 9-month-old rats. Since age difference could result in unparallelled change of the absorption and bioavailability of the polymorphic drugs, the results in this experiment are of value for further investigation of crystal form selection in clinical trials and rational clinical application of the polymorphic drugs.