The assessment of absorption of periplocin in situ via intestinal perfusion of rats by HPLC

Mechanism of XiJiaQi in the treatment of chronic heart failure: Integrated analysis by pharmacoinformatics, molecular dynamics simulation, and SPR validation

OBJECTIVE

Chronic heart failure (CHF) is a complicated clinical syndrome with a high mortality rate. XiJiaQi (XJQ) is a traditional Chinese medicine used in the clinical treatment of CHF, but its bioactive components and their modes of action remain unknown. This study was designed to unravel the molecular mechanism of XJQ in the treatment of CHF using multiple computer-assisted and experimental methods.

METHODS

Pharmacoinformatics-based methods were used to explore the active components and targets of XJQ in the treatment of CHF. ADMETlab was then utilized to evaluate the pharmacokinetic and toxicological properties of core components. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were to explore the underlying mechanism of XJQ treatment. Molecular docking, surface plasmon resonance (SPR), and molecular dynamics (MD) were employed to evaluate the binding of active components to putative targets.

RESULTS

Astragaloside IV, formononetin, kirenol, darutoside, periplocin and periplocymarin were identified as core XJQ-related components, and IL6 and STAT3 were identified as core XJQ targets. ADME/T results indicated that periplocin and periplocymarin may have potential toxicity. GO and KEGG pathway analyses revealed that XJQ mainly intervenes in inflammation, apoptosis, diabetes, and atherosclerosis-related biological pathways. Molecular docking and SPR revealed that formononetin had a high affinity with IL6 and STAT3. Furthermore, MD simulation confirmed that formononetin could firmly bind to the site 2 region of IL6 and the DNA binding domain of STAT3.

CONCLUSION

This study provides a mechanistic rationale for the clinical application of XJQ. Modulation of STAT3 and IL-6 by XJQ can impact CHF, further guiding research efforts into the molecular underpinnings of CHF.

Improving intestinal absorption and antibacterial effect of florfenicol via nanocrystallisation technology

To study the effects of nanocrystallisation technology on the intestinal absorption properties and antibacterial activity of florfenicol (FF). The florfenicol nanocrystals (FF-NC) were prepared by wet grinding and spray drying. Additionally, changes in particle size, charge, morphology, and dissolution of FF-NC in the long-term stability were monitored by laser particle sizer, TEM, SEM, paddle method, and the structure of FF-NC powder was characterised by nuclear magnetic resonance (NMR) test. The antibacterial activity, intestinal absorption and intestinal histocompatibility of FF-NC were investigated by the stiletto, mini broth dilution susceptibility test, in situ single-pass intestinal perfusion (SPIP) and haematoxylin-eosin (H-E) staining. After 12 months of storage, the particle size and zeta potential of FF-NC were 280.43 ± 8.21 nm and -19.64 ± 3.45 mV, and the electron microscopy results showed that FF-NC were nearly circular with no adhesion between particles. In addition, the drug loading, encapsulation efficiency, and dissolution of FF-NC did not change significantly during storage. The inhibition zone of FF-NC against Escherichia coli and Staphylococcus aureus was 21.37 ± 1.70 mm and 25.17 ± 2.47 mm, respectively. Compared with the FF, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of FF-NC are reduced, and the absorption rate constant (K_a) and efficient permeability coefficient (P_eff) of FF-NC in the three intestinal segments were increased by 1.28, 0.25, and 9.10 times and 0.59, 0.17, and 6.0 times, respectively. The results of tissue sections showed that FF-NC had little damage to the small intestinal. Nanocrystallisation technology is an effective method to increase the intestinal absorption and antibacterial activity of FF.

The Effect of Particle Size on the Absorption of Cyclosporin A Nanosuspensions

Background

Cyclosporin A (CsA) is a hydrophobic drug widely used as an immunosuppressant and anti-rejection drug in solid organ transplantation. On the market, there are two oral CsA formulations available containing polyoxyethylene castor oil, which can cause serious allergic reactions and nephrotoxicity. In order to eliminate polyoxyethylene castor oil, CsA was formulated into a nanosuspension. This study aimed to design an oral cyclosporin A nanosuspensions (CsA-NSs) and investigate the effect of particle size on absorption of CsA-NSs.

Methods

CsA-NSs were prepared using a wet bead milling method. Particle size, morphology and crystallinity state of CsA-NSs were characterized. The in vitro dissolution, the intestinal absorption properties and pharmacokinetic study of CsA-NSs were investigated.

Results

CsA-NSs with sizes of 280 nm, 522 nm and 2967 nm were prepared. The shape of CsA-NSs with smaller size was similar to that of spheres. The crystallinity of CsA in nanocrystals was reduced. The dissolution rate of CsA-NSs (280 nm) was greater than that of CsA-NSs (522 nm) and CsA-NSs (2967 nm). CsA-NSs (280 nm) showed higher absorption rate constants (K_α) and effective permeability coefficients (P_eff) of different intestinal segments compared with that of CsA-NSs (522 nm) and CsA-NSs (2967 nm). AUC_0-48h of 280 nm CsA-NSs was about 1.12-fold of that of 522 nm CsA-NSs, and about 1.51-fold of that of 2967 nm CsA-NSs. In particular, the particle size of CsA-NSs was nanoscale, and their bioavailability was bioequivalent with marked self-microemulsion (Sandimmun Neoral^®).

Conclusion

It is feasible to prepare CsA-NSs. The dissolution rate, gastrointestinal transport properties and the oral absorption of CsA-NSs were promoted by reducing size. Considering the cost, efficiency and energy consumption, there should be an optimal particle size range in industrial production.

In Vitro Metabolic Profiling of Periplogenin in Rat Liver Microsomes and its Associated Enzyme-kinetic Evaluation

Background:

Periplogenin, an active ingredient in Cortex Periplocae, is widely noted for its multiple biological activities; however, the metabolism of this compound has been scarcely investigated. The present report proposed the in vitro metabolic profiling and reaction pathways of periplogenin in rat liver microsomes.

Method and Results:

The metabolites of periplogenin in rat liver microsomes were analyzed. Two main metabolites, namely 14-hydroxy-3-oxo-14β-carda-4, 20 (22)-dienolide and 5, 14-dihydroxy-3-oxo-5β, 14β-card-20(22)-enolide were identified by HPLC-MSn, 1H-NMR and 13C-NMR. HPLC method was established for the simultaneous determination of periplogenin and its related metabolites (M0, M1 and M2), which was performed on Waters ODS column with a methanol-water solution (53:47, v/v) as mobile phase and descurainoside as an internal standard at 220 nm. The linearity ranges of M0, M1 and M2 were 0.64-820.51, 0.68-864.86 and 0.64-824.74 μM respectively with the regression coefficient (R2) above 0.9995. The limits of quantitation for these metabolites (M0, M1 and M2) were 0.18, 0.22 and 0.15 μM respectively. The developed method was also accurate (with relative errors of -3.6% to 3.2%) and precise (with relative standard deviations below 7.9%). The recoveries of the three analytes were above 85.7% with stability in the range of -2.4% to 3.6%. The enzyme-kinetic parameters of periplogenin including Vmax (6.08 ± 0.19 nmol/mg protein/min), Km (288.62 ± 14.54 μM) and Clint (21 ± 1.0 μL/min/mg protein) were calculated using nonlinear regression analysis.

Conclusion:

These findings significantly highlighted the metabolic pathways of periplogenin and also provided some reference data for future pharmacokinetic and pharmacodynamic studies.

An LC-MS/MS Method for Simultaneous Determination of the Toxic and Active Components of Cortex Periplocae in Rat Plasma and Application to a Pharmacokinetic Study

A sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine the toxic and other active components including isovanillin, scopoletin, periplocin, periplogenin, and periplocymarin after oral administration of cortex periplocae extract to rats. Plasma samples were prepared by protein precipitation with methanol. All compounds were separated on a C₁₈ column with gradient elution using acetonitrile and formic acid aqueous solution (0.1%, v/v) as the mobile phase at a flow rate of 0.3 mL/min. The detection of all compounds was accomplished by multiple-reaction monitoring (MRM) in the positive electrospray ionization mode. The LC-MS/MS method exhibited good linearity for five analytes. The lower limit of quantification (LLOQ) was 0.48 ng/mL for scopoletin, periplogenin, and periplocymarin; 2.4 ng/mL for isovanillin and periplocin. The extraction recoveries of all compounds were more than 90% and the RSDs were below 10%. It was found that the absorption of scopoletin and periplocin was rapid in vivo after oral administration of cortex periplocae extract. Furthermore, periplocymarin possessed abundant plasma exposure. The results demonstrated that the validated method was efficiently applied for the pharmacokinetic studies of isovanillin, scopoletin, periplocin, periplogenin, and periplocymarin after oral administration of cortex periplocae extract.

Gene expression profiling of the proliferative effect of periplocin on mouse cardiac microvascular endothelial cells

OBJECTIVE

Periplocin is an active digitalis-like component from Cortex Periplocae, which has been widely used in the treatment of heart diseases in China for many years. According to the recommendations on the cardiovascular effect of periplocin from in vivo experiments, subsequent in vitro experiments are greatly needed for the global assessment of periplocin. The objective of this study is to investigate the cell proliferation effect and the mechanism of periplocin on endothelial cells.

METHODS

The proliferative activity of periplocin (0.4, 2, 10, 50, 250 micromol/L; 6, 12, 24, 48, 72 h) was investigated by a comparison with the well-reported cardiac glycoside, ouabain, on mouse cardiac microvascular endothelial cells (CMEC). 3-(4,5-dimethylthiazolyl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) and 5-bromo-2-deoxyuridine (BrdU) assays were used to evaluate cell proliferation and viability. Subsequently, cDNA microarray experiments were performed on periplocin- (50 micromol/L) and ouabain- (50 micromol/L) treated cells, and data was analyzed by ArrayTrack software.

RESULTS

Periplocin could increase cell viability to a level lower than ouabain in the MTT analysis, but decrease LDH release simultaneously. The BrdU incorporation assay showed an increase in cell proliferation with 2-50 micromol/L periplocin. Genes related to protein serine/threonine kinase were the most significantly enriched in the 160 genes identified in periplocin versus the control. In the 165 genes regulated by periplocin versus ouabain, GTP-binding was the most altered term.

CONCLUSIONS

The results demonstrated the proliferation action of periplocin on CMEC. Meanwhile, its lower cytotoxicity compared to ouabain provides a new insight into the treatment of heart failure.