advanced crystallization
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Many active pharmaceutical ingredients (APIs) are poorly soluble and therefore poorly bioavailable. In recent years, the advances in crystal engineering have motivated the research in the design of pharmaceutical co-crystals. This study examines the combination of solvent selection and co-crystal ternary phase diagram prediction on the basis of solubility measurements into a single methodology that can be integrated into the pharmaceutical process development workflow. Ternary diagrams constructed from agomelatine citric acid co-crystal solubility data were compared with those obtained by modern calorimetric method called discontinuous isoperibolic thermal analysis (DITA). A suitable solvent for the co-crystallization process has been chosen on the basis of agomelatine citric acid co-crystal solubility, which is connected to the yield of the crystallization process. Furthermore, the quality of final crystals from crystallization experiments was evaluated.
Pacienti s metastatickým kolorektálním karcinomem KRAS wild formou mohou výrazněji profitovat z paliativní chemoterapie, nicméně právě u nich může být léčba ještě účinnější při přidání antiEGFR protilátek - cetuximabu nebo panitumumabu. V uvedené kazuistice se nastavení léčby opíralo o výsledky studie CRYSTAL, OPUS, EPIC a NCIC CTC CO.17 .
Patients with metastatic colorectal carcinoma expressive the wild-type KRAS gene can profit more significantly from palliative chemotherapy, however in these patients specifically, the therapy can be made even more effective by adding anti-EGFR antibodies - cetuximab or panitumumab. In the presented case study, the therapy settings was based on the results of the following studies: CRYSTAL, OPUS, EPIC, NCIC CTC CO.17.
- MeSH
- adjuvantní chemoterapie * metody MeSH
- epidermální růstový faktor antagonisté a inhibitory MeSH
- kamptothecin aplikace a dávkování MeSH
- katetrizační ablace metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- lymfatické metastázy MeSH
- monoklonální protilátky aplikace a dávkování škodlivé účinky MeSH
- nádory jater chirurgie sekundární MeSH
- nádory rekta * farmakoterapie chirurgie mortalita patologie radioterapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
Despite recent advances in solid-state NMR spectroscopy, the structural characterization of amorphous active pharmaceutical ingredients (APIs) in solid dosage forms continues to be a monumental challenge. To circumvent complications following from low concentrations of APIs in tablet formulations, we propose a new time-saving procedure based on chemometric approach: factor analysis of (19)F MAS NMR spectra. Capability of the proposed method is demonstrated on atorvastatin--a typical representative of fluorinated pharmaceutical substances exhibiting extensive polymorphism. Applying the factor analysis on the recorded (19)F MAS NMR spectra, unique parameters for every sample were derived. In this way every solid form of atorvastatin was characterized and clearly distinguishable even among various amorphous and disordered forms. The proposed method was also found to be suitable for both qualitative and quantitative analysis of mixtures of various forms of atorvastatin. Reliability of the proposed method was extensively examined by comparing the obtained results with other experimental techniques such as (13)C CP/MAS NMR, FTIR and XRPD. As highly linear correlations between the sets of parameters obtained from different experimental data were found, the perspectives of the applied comparative factor analysis to obtain detail structural view on variability of amorphous forms of atorvastatin are also discussed. Although the reported method was tested on atorvastatin, authors expect wider application for any fluorinated compound to give the routine, fast and reliable characterization of amorphous forms of APIs in drug products even at low concentrations (1-5%). Bear in mind that 20-25% of currently developed pharmaceuticals contain at least one fluorine atom in the molecule.
- MeSH
- časové faktory MeSH
- faktorová analýza statistická MeSH
- fluor chemie MeSH
- krystalizace MeSH
- kyseliny heptylové chemie MeSH
- magnetická rezonanční spektroskopie metody MeSH
- prášková difrakce MeSH
- pyrroly chemie MeSH
- reprodukovatelnost výsledků MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Spray drying and hot-melt extrusion are among the most prevalent preparation techniques used in the pharmaceutical industry to produce amorphous solid dispersions (ASDs). This study advances previous research by integrating sample production, comprehensive analytical characterization, intrinsic dissolution rate measurements, and assessments of the behavior of ASDs under elevated temperature and humidity conditions. The study focuses on indomethacin, a widely used model for poorly soluble drugs, processed with PVP K30 or HPMC E5, both commonly used polymers. The findings demonstrate that hot-melt extruded samples exhibit superior stability against recrystallization, whereas spray dried samples achieve higher intrinsic dissolution rates. Furthermore, PVP K30 significantly outperforms HPMC E5 in the co-processing of indomethacin, enhancing both the intrinsic dissolution rate and the stability.
- MeSH
- deriváty hypromelózy chemie MeSH
- farmaceutická chemie metody MeSH
- indomethacin * chemie MeSH
- krystalizace * MeSH
- povidon chemie MeSH
- příprava léků metody MeSH
- rozpustnost * MeSH
- sprejové sušení * MeSH
- stabilita léku * MeSH
- technologie extruze tavenin * metody MeSH
- uvolňování léčiv MeSH
- vlhkost MeSH
- vysoká teplota MeSH
- vysoušení metody MeSH
- Publikační typ
- časopisecké články MeSH
The virulence of the Candida pathogens is enhanced by the production of secreted aspartic proteases, which therefore represent possible targets for drug design. Here, the crystal structure of the secreted aspartic protease Sapp2p from Candida parapsilosis was determined. Sapp2p was isolated from its natural source and crystallized in complex with pepstatin A, a classical aspartic protease inhibitor. The atomic resolution of 0.83 Å allowed the protonation states of the active-site residues to be inferred. A detailed comparison of the structure of Sapp2p with the structure of Sapp1p, the most abundant C. parapsilosis secreted aspartic protease, was performed. The analysis, which included advanced quantum-chemical interaction-energy calculations, uncovered molecular details that allowed the experimentally observed equipotent inhibition of both isoenzymes by pepstatin A to be rationalized.
- MeSH
- aspartátové proteasy chemie genetika izolace a purifikace metabolismus MeSH
- Candida chemie enzymologie genetika MeSH
- exprese genu MeSH
- fungální proteiny chemie genetika izolace a purifikace metabolismus MeSH
- inhibitory proteas chemie MeSH
- izoenzymy chemie genetika izolace a purifikace metabolismus MeSH
- katalytická doména MeSH
- kinetika MeSH
- krystalografie rentgenová MeSH
- kvantová teorie MeSH
- molekulární modely MeSH
- molekulární sekvence - údaje MeSH
- pepstatiny chemie MeSH
- sekundární struktura proteinů MeSH
- sekvence aminokyselin MeSH
- sekvenční seřazení MeSH
- strukturní homologie proteinů MeSH
- substrátová specifita MeSH
- termodynamika MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nanosponges with three-dimensional (3D) porous structures, narrow size distribution, and high entrapment efficiency are widely engineered for cancer therapy and drug delivery purposes. They protect the molecular agents from degradation and help to improve the solubility of lipophilic therapeutic agents/drugs with targeted delivery options in addition to being magnetized to attain suitable magnetic features. Nanosponge-based delivery systems have been applied for cancer therapy with high specificity, biocompatibility, degradability, and prolonged release behavior. In this context, the drug loading within nanosponges is influenced by the crystallization degree. Notably, 3D printing technologies can be applied for the development of novel nanosponge-based systems for biomedical applications. The impacts of polymers, cross-linkers, type of drugs, temperature, loading and mechanism of drug release, fabrication methods, and substitution degree ought to be analytically evaluated. Eco-friendly techniques for the manufacturing of nanosponges still need to be uncovered in addition to the existing methods, such as solvent techniques, ultrasound-assisted preparation, melting strategies, and emulsion solvent diffusion methods. Herein, the recent advancements associated with the drug delivery and cancer therapy potential of nanosponges (chiefly, cyclodextrin-based, DNAzyme, and ethylcellulose nanosponges) are deliberated, focusing on the important challenges and future perspectives.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Smart materials of biological origin are attracting a lot of attention nowadays, especially as catalysts, carriers or adsorbents. Among them, magnetically modified biomaterials are especially important due to their response to external magnetic field. This report demonstrates that naturally occurring micrometer sized, high aspect ratio material (native and autoclaved Leptothrix sp. sheaths) efficiently bind synthetically prepared magnetite and maghemite nanoparticles and their aggregates. Magnetic modification of Leptothrix sheaths enables to prepare a promising material for advanced biotechnology and environmental technology applications. The prepared magnetically responsive sheaths were tested as inexpensive adsorbent for crystal violet removal from aqueous solutions. The observed maximum adsorption capacity was 243.1mg of dye per 1g of adsorbent.
- MeSH
- genciánová violeť chemie MeSH
- Leptothrix chemie MeSH
- magnetické nanočástice chemie MeSH
- Publikační typ
- časopisecké články MeSH
In January 2019, the ERA-EDTA surveyed nephrologists with questions on kidney care and kidney research designed to explore comprehension of the impact of alterations to organization of renal care and of advancements in technology and knowledge of kidney disease. Eight hundred and twenty-five ERA-EDTA members, ∼13% of the whole ERA-EDTA membership, replied to an ad hoc questionnaire. More than half of the respondents argued that kidney centres will be increasingly owned by large dialysis providers, nearly a quarter of respondents felt that many medical aspects of dialysis will be increasingly overseen by non-nephrologists and a quarter (24%) also believed that the care and long-term follow-up of kidney transplant patients will be increasingly under the responsibility of transplant physicians caring for patients with any organ transplant. Nearly half of the participants (45%, n = 367) use fully electronic clinical files integrating the clinical ward, the outpatient clinics, the haemodialysis and peritoneal dialysis units, as well as transplantation. Smartphone-based self-management programmes for the care of chronic kidney disease (CKD) patients are scarcely applied (only 11% of surveyed nephrologists), but a substantial proportion of respondents (74%) are eager to know more about the potential usefulness of these apps. Finally, European nephrologists expressed a cautious optimism about the application of omic sciences to nephrology and on wearable and implantable kidneys, but their expectations for the medium term are limited.
Guanine-rich DNA has the potential to fold into non-canonical G-quadruplex (G4) structures. Analysis of the genome of the social amoeba Dictyostelium discoideum indicates a low number of sequences with G4-forming potential (249-1055). Therefore, D. discoideum is a perfect model organism to investigate the relationship between the presence of G4s and their biological functions. As a first step in this investigation, we crystallized the dGGGGGAGGGGTACAGGGGTACAGGGG sequence from the putative promoter region of two divergent genes in D. discoideum. According to the crystal structure, this sequence folds into a four-quartet intramolecular antiparallel G4 with two lateral and one diagonal loops. The G-quadruplex core is further stabilized by a G-C Watson-Crick base pair and a A-T-A triad and displays high thermal stability (Tm > 90°C at 100 mM KCl). Biophysical characterization of the native sequence and loop mutants suggests that the DNA adopts the same structure in solution and in crystalline form, and that loop interactions are important for the G4 stability but not for its folding. Four-tetrad G4 structures are sparse. Thus, our work advances understanding of the structural diversity of G-quadruplexes and yields coordinates for in silico drug screening programs and G4 predictive tools.
- MeSH
- cirkulární dichroismus MeSH
- Dictyostelium genetika MeSH
- G-kvadruplexy * MeSH
- genom MeSH
- konformace nukleové kyseliny * MeSH
- krystalografie rentgenová MeSH
- molekulární modely MeSH
- mutace MeSH
- nukleární magnetická rezonance biomolekulární MeSH
- promotorové oblasti (genetika) MeSH
- spektrofotometrie ultrafialová MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
In over 40 years of research on the cellular uptake of auxin it is somewhat chastening that we have elaborated so little on the original kinetic descriptions of auxin uptake by plant cells made by Rubery and Sheldrake in 1974. Every aspect of that seminal work has been investigated in detail, and the uptake activity they measured is now known to be attributed to the AUX1/LAX family of permeases. Recent pharmacological studies have defined the substrate specificity of AUX1, biochemical studies have evaluated its permeability to auxin in plant cell membranes, and rigourous kinetic studies have confirmed the affinity of AUX1 for IAA and synthetic auxins. Advances in genome sequencing have provided a rich resource for informatic analysis of the ancestry of AUX1 and the LAX proteins and, along with models of topology, suggest mechanistic links to families of eukaryotic proton co-transporters for which crystal structures have been presented. The insights gained from all the accumulated research reflect the brilliance of Rubery and Sheldrake's early work, but recent biochemical analyses are starting to advance further our understanding of this vitally important family of auxin transport proteins.
