Effects of curcumin on the pharmacokinetics of amlodipine in rats and its potential mechanism

Dual strategy to improve the oral bioavailability of efavirenz employing nanomicelles and curcumin as a bio-enhancer

The present investigation was focused on the development of Soluplus®-based nanomicelles (NMs) (10 % w/v) loaded with Efavirenz (EFV) (5 mg/mL) and Curcumin (natural bio-enhancer) (CUR) (5, 10 and 15 mg/mL) to improve the oral bioavalability of EFV. Micellar formulations were obtained employing an acetone-diffusion technique. Apparent aqueous solubility was increased up to ∼1250-fold and 25,000-fold for EFV and CUR, respectively. Drug-loaded nanoformulations showed an excellent colloidal stability with unimodal size distribution and PDI values < 0.30. In vitro drug release was 41.5 % (EFV) and 2.6 % (CUR) from EFV-CUR-NMs over 6 h in simulated gastrointestinal fluids. EFV-CUR-loaded NMs resulted as safe nanoformulations according to the in vitro cytocompatibility assays in Caco-2 cells. Furthermore, CUR bio-enhancer activity was demonstrated for those nanoformulations. A CUR concentration of 15 mg/mL produced a significant (p < 0.05) increment (2.64-fold) of relative EFV oral bioavailability. Finally, the active role of the lymphatic system in the absorption process of EFV, after its oral administration was assessed in a comparative pharmacokinetic study in presence and absence of cycloheximide, a lymphatic transport inhibitor. Overall our EFV-CUR-NMs denoted their potential as a novel nanotechnological platform, representing a step towards an optimized "nano-sized" therapy for AIDS patients.

Tissue re-distribution of budesonide in rats co-administrated with curcumin by ultra performance liquid chromatography-tandem mass spectrometry

Budesonide (BUD), a locally acting glucocorticoid with low side effects, is recommended in several Crohn's disease (CD) drug treatment guidelines as the first choice for early treatment. Nevertheless, the extensive first-pass effect mediated by P-glycoprotein (P-gp) and Cytochrome P450 3A4 (CYP3A4) leads to low bioavailability and limits further applications. Curcumin (CUR), a natural polyphenol derived from turmeric, has been found to influence the in vivo processes of drugs by affecting the activity of P-gp and CYP3A4. However, the pharmacokinetic interactions between BUD and CUR remains elusive, so an ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of BUD and CUR in the tissue. The results showed that the area under the concentration-time curve 0 to time (AUC0→t) of BUD in the colon and kidney increased by approximately 32.35% and 39.03% respectively in the co-administered group compared to the single-drug group, while the small intestine, liver and plasma decreased by 80.03%, 67.34% and 24.34% respectively compared to the single-drug group. Therefore, long-term treatment with CUR can increase the concentration of BUD in the colonic area without increasing its systemic exposure, thus potentially reducing the incidence of side effects.

Cinnamon modulates the pharmacodynamic & pharmacokinetic of amlodipine in hypertensive rats

The objective of this study was to investigate the effects of cinnamon on the pharmacodynamic (PD) & pharmacokinetic (PK) of amlodipine in hypertensive rats. The hypertensive control group of Wistar rats received L-NAME (40 mg/kg, daily, orally) only. The cinnamon group of rats was treated with cinnamon (200 mg/kg, daily, orally) along with L-NAME. Following 14 days treatment period, blood pressures of rats were monitored at designated intervals over 24 h utilizing a tail-cuff system for measuring blood pressure. To assess the oral PK; amlodipine was administered as a single oral dose of 1 mg/kg to rats and blood samples were collected at specified intervals over 24 h and analysed by UPLC-LC MS/MS. Synergistic decreased in rat's blood pressure was observed in presence of cinnamon + amlodipine. Simultaneous administration of cinnamon ameliorates the Cmax and AUC0-t of amlodipine, the Cmax and AUC0-t was 11.04 ± 1.01 ng/ml and 113.76 ± 5.62 ng h/ml for the cinnamon + amlodipine group as compared to 4.12 ± 0.49 ng/ml and 48.59 ± 4.28 ng h/ml for the amlodipine alone group. The study demonstrates that the use of cinnamon considerably decreases the blood pressure levels and enhances the PK parameters of amlodipine in hypertensive rats.

Pharmacokinetic interaction between rhynchopylline and pellodendrine via CYP450 enzymes and P-gp

CONTEXT

Rhynchopylline and pellodendrine are major extractions of commonly used Chinese medicine in gynaecology. The interaction between these two compounds could affect treatment efficiency and even result in toxicity during their co-administration in gynaecological prescription.

OBJECTIVE

The pharmacokinetic interaction between rhynchopylline and pellodendrine and the potential mechanism were investigated in this study.

MATERIALS AND METHODS

Sprague-Dawley rats were randomly divided into four groups to investigate the pharmacokinetic interaction between rhynchopylline (30 mg/kg) and pellodendrine (20 mg/kg) with single dose of these two drugs as the control. The transport of rhynchopylline was evaluated in the Caco-2 cell model. Additionally, the metabolic stability and the activity of corresponding CYP450 enzymes were assessed in rat liver microsomes.

RESULTS

The pharmacokinetic profile of rhynchopylline was dramatically affected by pellodendrine with the increased area under the pharmacokinetic curve (3080.14 ± 454.54 vs. 1728.08 ± 220.598 μg/L*h), C_max (395.1 ± 18.58 vs. 249.1 ± 16.20 μg/L), prolonged t_1/2 (9.74 ± 2.94 vs. 4.81 ± 0.42 h) and the reduced clearance rate (from 11.39 ± 1.37 to 5.67 ± 1.42 L/h/kg). No significant changes were observed in the pharmacokinetics of pellodendrine. The transport of rhynchopylline was significantly inhibited by pellodendrine with a decreasing efflux ratio (1.43 vs. 1.79). Pellodendrine significantly inhibited the activity of CYP1A2 and CYP2C9 with IC₅₀ values of 22.99 and 16.23 μM, which are critical enzymes responsible for the metabolism of rhynchopylline.

DISCUSSION AND CONCLUSIONS

The adverse interaction between rhynchopylline and pellodendrine draws attention to the co-administration of these two herbs and provides a reference for further investigations with a broader study population.

4-O-galloylalbiflorin inhibits the activity of CYP3A, 2C9, and 2D in human liver microsomes

The effect of 4-O-galloylalbiflorin on the activity of cytochrome P450 enzymes (CYP450s) is an important factor that may induce drug-drug interaction.The effect of 4-O-galloylalbiflorin on the activity of CYP450s was evaluated in the presence of 0, 2.5, 5, 10, 25, 50, and 100 μM 4-O-galloylalbiflorin in pooled human liver microsomes. The inhibition model and corresponding parameters were assessed b fitting with Lineweaver-Burk plots. The time-dependent study was performed with the incubation time of 0, 5, 10, 15, and 30 min.4-O-galloylalbiflorin significantly inhibited the activity of CYP3A, 2C9, and 2 D in a concentration-dependent manner with the IC50 values of 8.2, 13, and 11 μM, respectively. The inhibition of CYP3A was found to be non-competitive and time-dependent with the Ki value of 4.0 μM and the KI/Kinact value of 2.2/0.030 (μM·min). The inhibition of CYP2C9 and 2 D was not affected by the incubation time but was found to be competitive with the Ki values of 6.7 and 6.6 μM, respectively.The inhibitory effect of 4-O-galloylalbiflorin on the activity of CYP3A, 2C9, and 2 D implying the potential drug-drug interaction between 4-O-galloylalbiflorin and the drugs metabolized by these CYP450s.