During the stability evaluation of β-artemether containing finished drug products, a consistent and disproportional increase in the UV-peak areas of β-artemether degradation products, when compared ...to the peak area decline of β-artemether itself, was observed. This suggested that the response factors of the formed β-artemether degradants were significantly higher than β-artemether. Dry heat stressing of β-artemether powder, as a single compound, using different temperatures (125–150°C), times (10–90min) and environmental conditions (neutral, KMnO4 and zinc), resulted in the formation of 17 degradants. The vast majority of degradants seen during the long-term and accelerated ICH stability study of the drug product, were also observed here. The obtained stress results allowed the calculation of the overall average relative response factor (RRF) of β-artemether degradants, i.e. 21.2, whereas the individual RRF values of the 9 most prominent selected degradants ranged from 4.9 to 42.4. Finally, Ames tests were performed on β-artemether as well as a representative stressed sample mixture, experimentally assessing their mutagenic properties. Both were found to be negative, suggesting no mutagenicity problems of the degradants at high concentrations. Our general approach and specific results solve the developmental quality issue of mass balance during stability studies and the related genotoxicity concerns of the key antimalarial drug β-artemether and its degradants.
Analytical method development for peptides often proves challenging since these molecules can adsorb to the plastic or glass consumables used in the analysis. This adsorption causes considerable loss ...and unreliable results, especially in the lower concentration range. Therefore, a variety of antiadsorption strategies have previously been developed to cope with this adsorption, often however incompatible with direct liquid chromatography–mass spectrometry (LC–MS) analysis. Here, a novel antiadsorption diluent is introduced, based on controlled hydrolysis and precipitation of bovine serum albumin. This diluent considerably decreases the adsorption of certain peptides to glass. Moreover, it is LC–MS compatible and can also be used in combination with formic acid and/or acetonitrile addition.
Chemical Classification of Cyclic Depsipeptides Taevernier, Lien; Wynendaele, Evelien; Gevaert, Bert ...
Current protein & peptide science,
05/2017, Letnik:
18, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Cyclic depsipeptides (CDPs) are a family of cyclic peptide-related compounds, of which the ring is mainly composed of amino- and hydroxy acid residues joined by amide and ester bonds (at least one), ...leading to a wide diversity of fascinating chemical structures. They differ in both their ring structure and their side chains, especially by the nature of the unusual and non-amino acid building blocks. To date, however, there is no overall uniform chemical classification system available for CDPs and naming of the diverse family members is done rather arbitrarily. Therefore, a broad evaluation of different CDP structures is done, i.e., 1348 naturally occurring CDPs were included, and a straightforward chemical classification system using apparent chemical characteristics is proposed in order to organize the currently scattered CDP data. The overall validity of the classification approach is verified and the compounds categorized in the same groups are considered to be structurally related. This evaluation also revealed that traditionally formed CDP subfamilies, like the dolastatins, might be misleading from a chemical point of view given the structural differences in this subfamily. This up-to-date CDP overview enables peptide and natural product scientists to study the wide diversity in CDP structures, their chemical interrelationships and identification of existing and newly found CDPs. Together with the available information on the species producing these CDPs and their reported biological activities, this paper provides a useful tool to gain new insights into this diverse group of peptides.
Abstract
Quorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as ...interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by
Bacillus cereus
species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction.
Angiotensin-converting enzyme inhibitors (ACEi), angiotensin II receptor blockers (ARBs), and HMG-CoA reductase inhibitors ("statins") have been hypothesized to affect COVID-19 severity. However, up ...to now, no studies investigating this association have been conducted in the most vulnerable and affected population groups (ie, older adults residing in nursing homes). The objective of this study was to explore the association of ACEi/ARB and/or statins with clinical manifestations in COVID-19-infected older adults residing in nursing homes.
We undertook a retrospective multicenter cohort study to analyze the association between ACEi/ARB and/or statin use with clinical outcome of COVID-19. The outcomes were (1) serious COVID-19 defined as long-stay hospital admission or death within 14 days of disease onset, and (2) asymptomatic (ie, no disease symptoms in the whole study period while still being diagnosed by polymerase chain reaction).
A total of 154 COVID-19-positive subjects were identified, residing in 1 of 2 Belgian nursing homes that experienced similar COVID-19 outbreaks.
Logistic regression models were applied with age, sex, functional status, diabetes, and hypertension as covariates.
We found a statistically significant association between statin intake and the absence of symptoms during COVID-19 (odds ratio OR 2.91; confidence interval CI 1.27-6.71), which remained statistically significant after adjusting for covariates (OR 2.65; CI 1.13-6.68). Although the effects of statin intake on serious clinical outcome were in the same beneficial direction, these were not statistically significant (OR 0.75; CI 0.24-1.87). There was also no statistically significant association between ACEi/ARB and asymptomatic status (OR 2.72; CI 0.59-25.1) or serious clinical outcome (OR 0.48; CI 0.10-1.97).
Our data indicate that statin intake in older, frail adults could be associated with a considerable beneficial effect on COVID-19 clinical symptoms. The role of statins and renin-angiotensin system drugs needs to be further explored in larger observational studies as well as randomized clinical trials.
Recent research has provided fascinating indications and evidence that the host health is linked to its microbial inhabitants. Due to the development of high-throughput sequencing technologies, more ...and more data covering microbial composition changes in different disease types are emerging. However, this information is dispersed over a wide variety of medical and biomedical disciplines.
Disbiome is a database which collects and presents published microbiota-disease information in a standardized way. The diseases are classified using the MedDRA classification system and the micro-organisms are linked to their NCBI and SILVA taxonomy. Finally, each study included in the Disbiome database is assessed for its reporting quality using a standardized questionnaire.
Disbiome is the first database giving a clear, concise and up-to-date overview of microbial composition differences in diseases, together with the relevant information of the studies published. The strength of this database lies within the combination of the presence of references to other databases, which enables both specific and diverse search strategies within the Disbiome database, and the human annotation which ensures a simple and structured presentation of the available data.
Bacteria coordinate their behavior as a group via communication with their peers, known as 'quorum sensing'.
employs quorum sensing via RNPP-peptides which were not yet reported to be present in ...mammalian biofluids.
Solid phase extraction of murine feces was performed, followed by ultra high performance liquid chromatography (UHPLC-MS/MS) in multiple reaction monitoring (MRM) mode (in total <90 min/sample) for the nine known RNPP peptides. Limits of detection ranged between 0.045 and 52 nM. Adequate identification criteria allowed detection of RNPP quorum sensing peptides in 2/20 wild-type murine feces samples (i.e., cAM373 and cOB1).
A fit-for-purpose UHPLC-MS/MS method detected these RNPP peptides in wild-type murine feces samples.
Radiolabelled peptides and proteins have recently gained great interest as theranostics, due to their numerous and considerable advantages over small (organic) molecules. Developmental procedures of ...these radiolabelled biomolecules start with the radiolabelling process, greatly defined by the amino acid composition of the molecule and the radionuclide used. Depending on the radionuclide selection, radiolabelling starting materials are whether or not essential for efficient radiolabelling, resulting in direct or indirect radioiodination, radiometal-chelate coupling, indirect radiofluorination or (3)H/(14)C-labelling. Before preclinical investigations are performed, quality control analyses of the synthesized radiopharmaceutical are recommended to eliminate false positive or negative functionality results, e.g. changed receptor binding properties due to (radiolabelled) impurities. Therefore, radionuclidic, radiochemical and chemical purity are investigated, next to the general peptide attributes as described in the European and the United States Pharmacopeia. Moreover, in vitro and in vivo stability characteristics of the peptides and proteins also need to be explored, seen their strong sensitivity to proteinases and peptidases, together with radiolysis and trans-chelation phenomena of the radiopharmaceuticals. In vitro biomedical characterization of the radiolabelled peptides and proteins is performed by saturation, kinetic and competition binding assays, analyzing KD, Bmax, kon, koff and internalization properties, taking into account the chemical and metabolic stability and adsorption events inherent to peptides and proteins. In vivo biodistribution can be adapted by linker, chelate or radionuclide modifications, minimizing normal tissue (e.g. kidney and liver) radiation, and resulting in favorable dosimetry analyses. Finally, clinical trials are initiated, eventually leading to the marketing of radiolabelled peptides and proteins for PET/SPECT-imaging and therapy of different clinical diseases.
L-asparaginase is an effective anti-tumor agent for acute lymphoblastic leukemia. This work presents the development of an activity determination of L-ASNase preparations for pharmaceutical quality ...control purposes, in accordance with analytical Quality by Design principles. Critical method attributes, the absorbance at 450 nm (A450) of the Nessler product as well as its variability, were evaluated as a function of critical method variables, by using experimental designs. The design space of the enzyme activity assay was defined (Nessler method: C(KI)/C(HgI2) of 1.90-1.95, C(NaOH)/C(HgI2) of 17.0-18.0, C(HgI2final) of 20-40 mM and time of 10-40 min; enzyme activity conditions: temperature range of 36.6-37.4 °C, pH range of the KH2PO4 buffer from 7.1 to 7.7, KH2PO4 buffer concentration: 0.18-0.22 M and L-Asn concentration of 18-22 mM), leading to a final enzyme activity assay method. A control strategy was ultimately implemented using system suitability tests.
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