Teriflunomide Is an Indirect Human Constitutive Androstane Receptor (CAR) Activator Interacting With Epidermal Growth Factor (EGF) Signaling

The constitutive androstane receptor (CAR) is a nuclear receptor involved mainly in xenobiotic and endobiotic metabolism regulation. CAR is activated directly by its ligands via the ligand binding domain (LBD) or indirectly by inhibition of the epidermal growth factor (EGF) signaling. We found that leflunomide (LEF) and its main metabolite teriflunomide (TER), both used for autoimmune diseases treatment, induce the prototype CAR target gene CYP2B6 in primary human hepatocytes. As TER was discovered to be an EGF receptor antagonist, we sought to determine if TER is an indirect activator of CAR. In primary human hepatocytes and in differentiated HepaRG cells, we found that LEF and TER up-regulate CAR target genes CYP2B6 and CYP3A4 mRNAs and enzymatic activities. TER stimulated CAR+A mutant translocation into the nucleus but neither LEF nor TER activated the CAR LBD, CAR3 variant or pregnane X receptor (PXR) in gene reporter assays. Interestingly, TER significantly up-regulated CAR mRNA expression, a result which could be a consequence of both EGF receptor and ELK-1 transcription factor inhibition by TER or by TER-mediated activation of glucocorticoid receptor (GR), an upstream hormonal regulator of CAR. We can conclude that TER is a novel indirect CAR activator which through EGF inhibition and GR activation controls both detoxification and some intermediary metabolism genes

Influence of Amlodipine Enantiomers on Human Microsomal Cytochromes P450: Stereoselective Time-Dependent Inhibition of CYP3A Enzyme Activity

Amlodipine (AML) is available as a racemate, i.e., a mixture of R- and S-enantiomers. Its inhibitory potency towards nine cytochromes P450 (CYP) was studied to evaluate the drug–drug interactions between the enantiomers. Enzyme inhibition was evaluated using specific CYP substrates in human liver microsomes. With CYP3A, both enantiomers exhibited reversible and time-dependent inhibition. S-AML was a stronger reversible inhibitor of midazolam hydroxylation: the Ki values of S- and R-AML were 8.95 µM, 14.85 µM, respectively. Computational docking confirmed that the enantiomers interact differently with CYP3A: the binding free energy of S-AML in the active site was greater than that for R-AML (−7.6- vs. −6.7 kcal/mol). Conversely, R-AML exhibited more potent time-dependent inhibition of CYP3A activity (KI 8.22 µM, Kinact 0.065 min−1) than S-AML (KI 14.06 µM, Kinact 0.041 min−1). R-AML was also a significantly more potent inhibitor of CYP2C9 (Ki 12.11 µM/S-AML 21.45 µM) and CYP2C19 (Ki 5.97 µM/S-AML 7.22 μM. In conclusion, results indicate that clinical use of S-AML has an advantage not only because of greater pharmacological effect, but also because of fewer side effects and drug–drug interactions with cytochrome P450 substrates due to absence of R-AML

Branched PLGA derivatives with tailored drug delivery properties

Despite several shortcomings such as extreme hydrophobicity, low drug capacity, characteristic triphasic drug release pattern with a high burst effect, poly(lactic-co-glycolic acid derivatives are widely used in drug delivery. Most frequent attempts to improve their properties are blending with other polymers or synthesis of block copolymers. We introduce a new class of branched poly(lactic-co-glycolic acid) derivatives as promising biodegradable carriers for prolonged or targeted drug release systems, employed as thin adhesive films, solid dispersions, in situ forming implants or nanoparticles. A series of poly(lactic-co-glycolic acid) derivatives with lower molar mass and star or comb architecture were synthesized by a simple, catalyst free, direct melt polycondensation method not requiring purification of the obtained sterile product by precipitation. Branching monomers used were mannitol, pentaerythritol, dipentaerythritol, tripentaerythritol and polyacrylic acid. The products were characterized by molar mass averages, average branching ratio, rheological and thermal properties

Rozvětvené deriváty PLGA s řízenými drug-delivery vlastnostmi

Despite several shortcomings such as extreme hydrophobicity, low drug capacity, characteristic triphasic drug release pattern with a high burst effect, poly(lactic-co-glycolic acid derivatives are widely used in drug delivery. Most frequent attempts to improve their properties are blending with other polymers or synthesis of block copolymers. We introduce a new class of branched poly(lactic-co-glycolic acid) derivatives as promising biodegradable carriers for prolonged or targeted drug release systems, employed as thin adhesive films, solid dispersions, in situ forming implants or nanoparticles. A series of poly(lactic-co-glycolic acid) derivatives with lower molar mass and star or comb architecture were synthesized by a simple, catalyst free, direct melt polycondensation method not requiring purification of the obtained sterile product by precipitation. Branching monomers used were mannitol, pentaerythritol, dipentaerythritol, tripentaerythritol and polyacrylic acid. The products were characterized by molar mass averages, average branching ratio, rheological and thermal properties.Přes některé nedostatky, deriváty kyseliny poly(mléčné-co-glykolové) jsou široce používány jako drug-delivery materiály. Práce představuje nový typ větvené kyseliny poly(mléčné-co-glykolové) jako slibného biodegradabilního materiálu. Série větvené kyseliny poly(mléčné-co-glykolové) byla připravena přímou kondenzací v tavenině bez použití katalyzátoru. Získané produkty nevyžadovaly čištění srážením. Jako větvící monomery byly použity mannitol, pentaerythritol, dipentaerythritol, tripentaerythritol and kyselina polyakrylová. Produkty byly charakterizovány molární hmotností, průměrným větvícím poměrem a rheologickými a termálními vlastnostmi

Synthesis of Novel Pyrazinamide Derivatives Based on 3-Chloropyrazine-2-carboxamide and Their Antimicrobial Evaluation

Aminodehalogenation of 3-chloropyrazine-2-carboxamide with variously substituted benzylamines yielded a series of fifteen 3-benzylaminopyrazine-2-carboxamides. Four compounds possessed in vitro whole cell activity against Mycobacterium tuberculosis H37Rv that was at least equivalent to that of the standard pyrazinamide. MIC values ranged from 6 to 42 μM. The best MIC (6 μM) was displayed by 3-[(4-methylbenzyl)amino]pyrazine-2-carboxamide (8) that also showed low cytotoxicity in the HepG2 cell line (IC50 ≥ 250 μM). Only moderate activity against Enterococcus faecalis and Staphylococcus aureus was observed. No activity was detected against any of tested fungal strains. Molecular docking with mycobacterial enoyl-ACP reductase (InhA) was performed to investigate the possible target of the prepared compounds. Active compounds shared common binding interactions of known InhAinhibitors. Antimycobacterial activity of the title compounds was compared to the previously published benzylamino-substituted pyrazines with differing substitution on the pyrazine core (carbonitrile moiety). The title series possessed comparable activity and lower cytotoxicity than molecules containing a carbonitrile group on the pyrazine ring

Oligonucleotide Delivery across the Caco-2 Monolayer: The Design and Evaluation of Self-Emulsifying Drug Delivery Systems (SEDDS)

Oligonucleotides (OND) represent a promising therapeutic approach. However, their instability and low intestinal permeability hamper oral bioavailability. Well-established for oral delivery, self-emulsifying drug delivery systems (SEDDS) can overcome the weakness of other delivery systems such as long-term instability of nanoparticles or complicated formulation processes. Therefore, the present study aims to prepare SEDDS for delivery of a nonspecific fluorescently labeled OND across the intestinal Caco-2 monolayer. The hydrophobic ion pairing of an OND and a cationic lipid served as an effective hydrophobization method using either dimethyldioctadecylammonium bromide (DDAB) or 1,2-dioleoyl-3-trimethylammonium propane (DOTAP). This strategy allowed a successful loading of OND-cationic lipid complexes into both negatively charged and neutral SEDDS. Subjecting both complex-loaded SEDDS to a nuclease, the negatively charged SEDDS protected about 16% of the complexed OND in contrast to 58% protected by its neutral counterpart. Furthermore, both SEDDS containing permeation-enhancing excipients facilitated delivery of OND across the intestinal Caco-2 cell monolayer. The negatively charged SEDDS showed a more stable permeability profile over 120 min, with a permeability of about 2 × 10−7 cm/s, unlike neutral SEDDS, which displayed an increasing permeability reaching up to 7 × 10−7 cm/s. In conclusion, these novel SEDDS-based formulations provide a promising tool for OND protection and delivery across the Caco-2 cell monolayer