Chemical aspects of influence of medical drugs on organism functions

Some fundamental problems of pharmacology important for setting investigations dealing with the search for new effective drugs are considered. The ways of introduction of drugs into the body, the types and functions of biological membranes, mediators of central and peripheral nervous systems, various receptor systems, and enzyme inhibitors are discussed.     

哌嗪嘧啶类CCR4拮抗剂的设计、合成及生物活性

基于对已报道的CCR4拮抗剂的构效关系分析, 设计并合成了一系列哌嗪嘧啶类化合物. 采用细胞趋化抑制实验测试了合成化合物的体外活性, 其中化合物8a的活性优于目前报道的活性最好的化合物BMS-397; 在小鼠鼻炎模型中, 化合物8a以极低的剂量达到了布地奈德(鼻炎临床治疗药物)的治疗效果. 采用毛细管电泳法测得化合物8a与CCR4 N端40肽的结合常数为(3.6179±0.5976)×10⁴ L/mol.     

Development of a liquid-liquid extraction procedure for five 1,4-dihydropyridines calcium channel antagonists from human plasma using experimental design

A liquid–liquid extraction method using diethyl ether as organic solvent was optimized simultaneously for five 1,4-dihydropyridines (amlodipine, nitrendipine, felodipine, lacidipine and lercanidipine) belonging to the group of calcium channel blockers. Some experimental tools such as a full factorial design, a central composite design and the Multisimplex program were used to optimise the concentration of NaOH, volume of organic solvent and shaking time as main factors that influence the liquid–liquid extraction procedure. Following the extraction, the quantitation of the 1,4-dihydropyridines concentrations were performed by high-performance liquid chromatography with diode-array detector. Therefore, the studied compounds were separated quantitatively on a Supelcosil ABZ+Plus, 25 cm × 4.6 mm i.d., 5 μm column which was set at 30 °C, using as mobile phase, a mixture of acetonitrile–water (70:30, v/v) containing 10 mM acetate buffer (pH 5) and setting the detector at a wavelength value of 360 nm. It was concluded that the main factors that influence in the extraction process were the volume of organic solvent and the shaking time. The Multisimplex program suggested as optimal conditions an average of 6 ml of organic solvent and 23 min of shaking time. For these values, the optimised liquid–liquid extraction method showed good values of recoveries (80% for amlodipine and higher than 90% for the rest of the compounds) and low values of R.S.D. (<10%) in the reproducibility of the extraction what makes it reliable for the quantification of all the studied compounds in human plasma.     

SYNTHESIS AND BIOACTIVITIES OF NEW LHRH ANTAGONISTS CONTAINING NOVEL UNNATURAL AMINO ACIDS AT POSITION FIVE

Synthesis and bioactivities of new antagonists of luteinizing hormone releasing hormone(LHRH) with novel unnatural amino acids at position five are reported, Most of them showedsome antiovulatory activity at 0. 5μg/rat and two of them inhibited ovulation completely at1μg/rat using saline as vehicle.     

CCR1 antagonists

CCR1 (CC Chemokine receptor 1) is a widely studied G protein-coupled receptor target expressed on multiple types of leukocytes. It is implicated in initiating and exacerbating inflammatory conditions and thus is viewed as a good target for autoimmune and inflammatory therapeutic applications. Numerous CCR1 antagonists have been reported. Although some early CCR1 antagonists lacked the species cross reactivity that made in vivo animal model study difficult, efforts have been made to improve the compound potency in rodents. Recent identification of new and improved CCR1 antagonists has resulted in promising, in vivo efficacy in a variety of animal models of disease. While several early compounds have been withdrawn from clinical trials due to lack of efficacy, work continues to evaluate CCR1 antagonists in preclinical and clinical settings.     

Crystal and molecular structures of 1,4-dihydro-6-methyl-5-N,N-diethylcarbamoyl-4-phenyl-2(3H)-pyrimidinethione (1) and 1,4-dihydro-6-methyl-5-N-methyl carbamoyl-4-(2′-nitrophenyl)-2(3H)-pyrimidinethione hemihydrate (2)

The crystal structure of 1,4-dihydro-6-methyl-5-N,N-diethylcarbamoyl-4-phenyl-2(3H)-pyrimidinethione, C₁₆ H ₂₁ N ₃OS (1), is monoclinic, space group P2₁/n, a = 6.818(1), b = 13.211(2), c = 18.807(3) Å, = 99.53(1)°, V = 1670.6(4) ų, Z = 4 and d _cal = 1.206 Mg/m³, R = 0.042 (wR = 0.119) for 190 parameters and 2560 observations with I 2(I) and 1,4-dihydro-6-methyl-5-N-methyl carbamoyl-4-(2-nitrophenyl)-2(3H)-pyrimidinethione hemihydrate, C₁₃ H ₁₄N₄O₃S 0.5H₂O, (2), is triclinic, space group P1, a = 7.513(1), b = 14.381(2), c = 15.506(2)Å, = 114.95(2), = 98.11(1), = 93.55(1)°, V = 1490.0(3) ų, Z = 4 and d _cal = 1.406 Mg/m³, R = 0.062 (wR = 0.165) for 388 parameters and 3094 observations with I 2(I).The compound 2 crystallized having two molecules in the asymmetric unit, which can be regarded as monohydrated dimers, and forming a hydrate. The conformation of the central heterocyclic ring (1,4-dihydropyrimidine) in both compounds was found to be close to a half-chair conformation. The 2-nitrophenyl substituent in 2 is in the axial synperiplanar orientation. In both compounds, the conformation of the 3-substituted carbamoyl group appears to be influenced by hydrogen bonding with anticlinal orientation observed for carbonyl groups serving as hydrogen bonding acceptors.     

Cyclic RGD and isoDGR Integrin Ligands Containing cis-2-amino-1-cyclopentanecarboxylic (cis-β-ACPC) Scaffolds

Integrin ligands containing the tripeptide sequences Arg-Gly-Asp (RGD) and iso-Asp-Gly- Arg (isoDGR) were actively investigated as inhibitors of tumor angiogenesis and directing unit in tumor-targeting drug conjugates. Reported herein is the synthesis, of two RGD and one isoDGR cyclic peptidomimetics containing (1S,2R) and (1R,2S) cis-2-amino-1-cyclopentanecarboxylic acid (cis-β-ACPC), using a mixed solid phase/solution phase synthetic protocol. The three ligands were examined in vitro in competitive binding assays to the purified α_vβ₃ and α₅β₁ receptors using biotinylated vitronectin (α_vβ₃) and fibronectin (α₅β₁) as natural displaced ligands. The IC50 values of the ligands ranged from nanomolar (the two RGD ligands) to micromolar (the isoDGR ligand) with a pronounced selectivity for α_vβ₃ over α₅β₁. In vitro cell adhesion assays were also performed using the human skin melanoma cell line WM115 (rich in integrin α_vβ₃). The two RGD ligands showed IC₅₀ values in the same micromolar range as the reference compound (cyclo[RGDfV]), while for the isoDGR derivative an IC₅₀ value could not be measured for the cell adhesion assay. A conformational analysis of the free RGD and isoDGR ligands by NMR (VT-NMR and NOESY experiments) and computational studies (MC/EM and MD), followed by docking simulations performed in the α_Vβ₃ integrin active site, provided a rationale for the behavior of these ligands toward the receptor.     

Fluorogenic Squaraine Dendrimers for Background-Free Imaging of Integrin Receptors in Cancer Cells

To overcome the limited brightness of existing fluorogenic molecular probes for biomolecular targets, we introduce a concept of fluorogenic dendrimer probe, which undergoes polarity-dependent switching due to intramolecular aggregation-caused quenching of its fluorophores. Based on a rational design of dendrimers with four and eight squaraine dyes, we found that octamer bearing dyes through a sufficiently long PEG(8) linker displays >400-fold fluorescence enhancement from water to non-polar dioxane. High extinction coefficient (≈2,300,000 m ⁻¹ cm⁻¹) resulted from eight squaraine dyes and quantum yield (≈25 %) make this octamer the brightest environment-sensitive fluorogenic molecule reported to date. Its conjugate with cyclic RGD used at low concentration (3 nm ) enables integrin-specific fluorescence imaging of cancer cells with high signal-to-background ratio. The developed dendrimer probe is a “golden middle” between molecular probes and nanoparticles, combining small size, turn-on response and high brightness, important for bioimaging.