RESUMO
The crystallographic study of two polymorphs of the industrial pyrazolone Pigment Orange 13 (P.O.13) is reported. The crystal structure of the ß phase was determined using single-crystal X-ray analysis of a tiny needle. The α phase was investigated using three-dimensional electron diffraction. The electron diffraction data contain sharp Bragg reflections and strong diffuse streaks, associated with severe stacking disorder. The structure was solved by careful analysis of the diffuse scattering, and similarities of the unit-cell parameters with the ß phase. The structure solution is described in detail and this provides a didactic example of solving molecular crystal structures in the presence of diffuse scattering. Several structural models were constructed and optimized by lattice-energy minimization with dispersion-corrected DFT. A four-layer model was found, which matches the electron diffraction data, including the diffuse scattering, and agrees with X-ray powder data. Additionally, five further phases of P.O.13 are described.
RESUMO
The quaternary structures of insulin glargine and glulisine under formulation conditions and upon dilution using placebo or water were investigated using synchrotron small-angle X-ray scattering. Our results revealed that insulin glulisine in Apidra® is predominantly hexameric in solution with significant fractions of dodecamers and monomers. Upon dilution with placebo, this equilibrium shifts towards monomers. Insulin glargine in Lantus® and Toujeo® is present in a stable hexamer/dimer equilibrium, which is hardly affected by dilution with water down to 1â¯mg/ml insulin concentration. The results provide exclusive insight into the quaternary structure and thus the association/dissociation properties of the two insulin analogues in marketed formulations.
Assuntos
Hipoglicemiantes/química , Insulina Glargina/química , Insulina/análogos & derivados , Humanos , Insulina/química , Modelos Moleculares , Estrutura Quaternária de ProteínaRESUMO
The design, synthesis, and structure-activity relationship of 1-phenoxy-2-aminoindanes as inhibitors of the Na+/H+ exchanger type 3 (NHE3) are described based on a hit from high-throughput screening (HTS). The chemical optimization resulted in the discovery of potent, selective, and orally bioavailable NHE3 inhibitors with 13d as best compound, showing high in vitro permeability and lacking CYP2D6 inhibition as main optimization parameters. Aligning 1-phenoxy-2-aminoindanes onto the X-ray structure of 13d then provided 3D-QSAR models for NHE3 inhibition capturing guidelines for optimization. These models showed good correlation coefficients and allowed for activity estimation. In silico ADMET models for Caco-2 permeability and CYP2D6 inhibition were also successfully applied for this series. Moreover, docking into the CYP2D6 X-ray structure provided a reliable alignment for 3D-QSAR models. Finally 13d, renamed as SAR197, was characterized in vitro and by in vivo pharmacokinetic (PK) and pharmacological studies to unveil its potential for reduction of obstructive sleep apneas.
Assuntos
Indanos/química , Indanos/farmacologia , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , Administração Oral , Animais , Células CACO-2 , Cristalografia por Raios X , Citocromo P-450 CYP2D6/metabolismo , Inibidores do Citocromo P-450 CYP2D6/administração & dosagem , Inibidores do Citocromo P-450 CYP2D6/química , Inibidores do Citocromo P-450 CYP2D6/farmacocinética , Inibidores do Citocromo P-450 CYP2D6/farmacologia , Desenho de Fármacos , Descoberta de Drogas , Humanos , Indanos/administração & dosagem , Indanos/farmacocinética , Modelos Moleculares , Relação Quantitativa Estrutura-Atividade , Ratos Sprague-Dawley , Trocador 3 de Sódio-Hidrogênio , Trocadores de Sódio-Hidrogênio/química , Trocadores de Sódio-Hidrogênio/metabolismo , SuínosRESUMO
The cis- and trans-isomers of the polycyclic aromatic compound perinone, C26H12N4O2, form a solid solution (Vat Red 14). This solid solution is isotypic to the crystal structures of cis-perinone (Pigment Red 194) and trans-perinone (Pigment Orange 34) and exhibits a combined positional and orientational disorder: In the crystal, each molecular position is occupied by either a cis- or trans-perinone molecule, both of which have two possible molecular orientations. The structure of cis-perinone exhibits a twofold orientational disorder, whereas the structure of trans-perinone is ordered. The crystal structure of the solid solution was determined by single-crystal X-ray analysis. Extensive lattice-energy minimizations with force-field and DFT-D methods were carried out on combinatorially complete sets of ordered models. For the disordered systems, local structures were calculated, including preferred local arrangements, ordering lengths, and probabilities for the arrangement of neighbouring molecules. The superposition of the atomic positions of all energetically favourable calculated models corresponds well with the experimentally determined crystal structures, explaining not only the atomic positions, but also the site occupancies and anisotropic displacement parameters.
RESUMO
Microbial natural products are a rich source of bioactive molecules to serve as drug leads and/or biological tools. We investigated a little-explored myxobacterial genus, Nannocystis sp., and discovered a novel 21-membered macrocyclic scaffold that is composed of a tripeptide and a polyketide part with an epoxyamide moiety. The relative and absolute configurations of the nine stereocenters was determined by NMR spectroscopy, molecular dynamics calculations, chemical degradation, and X-ray crystallography. The compound, named nannocystin A (1), was found to inhibit cell proliferation at low nanomolar concentrations through the early induction of apoptosis. The mode of action of 1 could not be matched to that of standard drugs by transcriptional profiling and biochemical experiments. An initial investigation of the structure-activity relationship based on seven analogues demonstrated the importance of the epoxide moiety for high activity.
Assuntos
Antifúngicos/química , Antineoplásicos/química , Produtos Biológicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Compostos Macrocíclicos/farmacologia , Myxococcales/fisiologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Produtos Biológicos/química , Candida albicans/efeitos dos fármacos , Cristalografia por Raios X , Descoberta de Drogas , Humanos , Compostos Macrocíclicos/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Otamixaban is a potent (Ki=0.5 nM) fXa inhibitor currently in late-stage clinical development at Sanofi for the management of acute coronary syndrome. Being unproductive in obtaining a suitable crystal of Otamixaban, the required enantiomeric characterization has been accomplished using vibrational circular dichroism (VCD) spectroscopy. Selected by a spectrum similarity index, the calculated spectra of several higher energy conformers were found to match well with the observed spectra. The characteristic IR bands of these conformers were also identified and attributed to the solvation effect. Combined with both the single crystal x-ray diffraction results for an intermediate and the proton NMR study, the absolute configuration of Otamixaban is unambiguously determined to be (R,R).
RESUMO
The solid-state development for the low dose drug molecule SAR114137, a selective and reversible inhibitor of cysteine cathepsin S/K, is reported. Six polymorphic forms as well as various solvate phases were discovered by an extensive polymorphism screening. The solid phase characterizations revealed that phase 1, from which a single crystal structure could be obtained, is the thermodynamically most stable form and therefore it was chosen for pharmaceutical development. The successful scale-up from development laboratory into pilot plant for the crystallization and drying processes is presented. Testing of different drying techniques, like agitated drying in conical or filter dryers as well as spray drying, proved them to be very promising alternatives to the conventional tray drying process and might be used during the industrialization phase of the project. The use of online analytical tools (e.g., Raman spectroscopy) for a better process understanding and as tools for process optimization is shown. Furthermore, wet milling by ultrasound was performed on laboratory scale and discussed as potential option to reach the desired particle size distribution necessary for a good content uniformity of the API in an oral formulation.
Assuntos
Catepsina K/antagonistas & inibidores , Catepsinas/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Varredura Diferencial de Calorimetria , Química Farmacêutica , Cristalografia por Raios X , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Microscopia Eletrônica de Varredura , Modelos Moleculares , Tamanho da Partícula , Projetos Piloto , Difração de Pó , Análise Espectral Raman , Termodinâmica , TermogravimetriaRESUMO
In an antibiotic lead discovery program, the known strain Streptomyces armeniacus DSM19369 has been found to produce three new natural products when cultivated on a malt-containing medium. The challenging structural elucidation of the isolated compounds was achieved by using three independent methods, that is, chemical degradation followed by NMR spectroscopy, a computer-assisted structure prediction algorithm, and X-ray crystallography. The compounds, named armeniaspirolâ A-C (2-4), exhibit a compact, hitherto unprecedented chlorinated spiro[4.4]non-8-ene scaffold. Labeling experiments with [1-(13)C] acetate, [1,2-(13)C2] acetate, and [U-(13)C] proline suggest a biosynthesis through a rare two-chain mechanism. Armeniaspirols displayed moderate to high in vitro activities against gram-positive pathogens such as methicillin-resistant S. aureus (MRSA) or vancomycin resistant E. faecium (VRE). As analogue 2 was active in vivo in an MRSA sepsis model, and showed no development of resistance in a serial passaging experiment, it represents a new antibiotic lead structure.