Molecular imprinting technology is a new analytical method that is highly selective and specific for certain analytes in artificial receptor design. The renewal possibilities of this technology make it an ideal material for sundry application fields. Molecularly imprinted polymers (MIPs) are polymeric matrices that have molecules printed on their surfaces; these surfaces can chemically interact with molecules or follow the pattern of the available template cavities obtained using imprinting technology. A MIP is useful for separating and analysing complex samples, such as biological fluids and environmental samples, because it is a strong analytical recognition element that can mimick natural recognition entities like biological receptors and antibodies. The MIP components consist of the target template, functional monomer, crosslinker, polymerisation initiator, and porogen. The effectiveness and selectivity of a MIP are greatly influenced by variations in the components. This review will provide an overview of the effect of MIP component ratio on analytical performance to each target analyte; it will also provide a strategy to obtain the best MIP performance. For every MIP, each template : monomer : crosslinker ratio shows a distinct performance for a specific analyte. The effects of the template : monomer : crosslinker ratio on a MIP’s analytical performances—measured by the imprinting factor, sorbent binding capacity, and sorbent selectivity—are briefly outlined.
Molecular imprinting has been broadly perceived as the most advanced
technology for preparing various materials that have a specific recognition
site with selective adsorption. MIPs (Molecular Imprinted Polymer) are
three-dimensional polymers with specific recognition sites for a certain
molecule. A MIP is formed by crosslinking template with monomers to create
copolymers. For every MIP, each template:monomer:crosslinker ratio shows a distinct
performance for a specific analyte. Ratio effect on analytical performances are
briefly outlined in this review. From all reports in this review, the synthesis
of MIP using a template:monomer:crosslinker ratio of 1:4:20 is more likely to
provide optimal imprinting efficiency.
We examined the physicochemical and biochemical properties of mono-O-(5,9,13-trimethyl-4-tetradecenyl)glycerol ester (MGE), including ease of handling, high bioadhesiveness, quick and stable in vivo self-organization (forming a non-lamellar lyotropic liquid crystal [NLLC]), and high biomembrane permeation enhancement. We prepared MGE oral mucosa-applied spray preparations containing triamcinolone acetonide (TA), which is widely used in the treatment of stomatitis, and we examined the usefulness of the MGE preparations compared with commercially available oral mucosal application preparations containing 2,3-dihydroxypropyl oleate (1-mono(cis-9-octadecenoyl)glycerol (GMO) (previously studied as an NLLC-forming lipid) preparation. As a result, the MGE preparation applied to the oral mucosa can rapidly formed an NLLC with reverse hexagonal or cubic structures, or a mixture, on contact with water. In addition, by adding hydroxypropyl cellulose to the MGE preparation, similar retention properties on the oral mucous membrane were obtained to that using marketed drug preparations. Furthermore, the MGE spray formulation on the oral mucosa showed an equivalent or higher TA release as well as oral mucous membrane permeability compared with commercial formulations. Because MGE forms a stable NLLC and is easy to handle compared with GMO, MGE was considered to be a useful pharmaceutical additive for a spray preparation applied to the oral mucosa in combination.
In line with the recent globalization of the drug supply chain and promotion of the use of generic drugs worldwide, quality assurance is required for drugs globally. In particular, controlling impurities is one of the biggest areas of interest regarding pharmaceutical quality, and it is desirable that the latest scientific standards harmonized in the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) are not only implemented in approval applications but also incorporated in pharmacopoeias which are public standards to ensure pharmaceutical quality more widely. However, incorporation into a pharmacopoeia takes time because careful consideration is required owing to the characteristics of a pharmacopoeia that is widely used for drugs, including those already on the market. To consider a smooth approach for the incorporation, we retrospectively examined approaches to incorporate the concepts of the ICH Q3C, Q3D, and M7 guidelines covering residual solvents, elemental impurities, and mutagenic impurities which are particularly toxic impurities into the European Pharmacopoeia, United States Pharmacopeia-National Formulary, and Japanese Pharmacopoeia, with approaches to implement these guidelines into approval processes in Europe, the U.S., and Japan. We also identified barriers and facilitators to this goal via cause and effect analysis. Moreover, we developed a logic model for the smooth incorporation of the concepts of impurity-related ICH guidelines. We expect that our proposed approach will be applied as a framework to smoothly incorporate the results of international harmonization activities for controlling impurities into each pharmacopoeia.
the globalization of the drug supply chain, the quality assurance of drugs is
required worldwide. Pharmacopoeias provide public standards for the drug quality
assurance, and smooth incorporation of the concepts of the international
guidelines into pharmacopoeias is desired. In particular, impurities in drugs
are to be controlled to ensure patient safety. The authors focused on the
harmonized guidelines for residual solvents, elemental impurities, and
mutagenic impurities, and proposed an approach for promoting incorporation of
the concepts of the guidelines into pharmacopoeias by combining the cause and
effect analysis and the logic model.
To accelerate drug development, the pharmaceutical industry is working to shorten and improve studies on stability. The Accelerated Stability Assessment Program (ASAP) incorporating the humidity-corrected Arrhenius equation as an accelerated methodology has been proposed for both drug substances and drug products. In this study, the effect of magnesium stearate (MgSt) content on the chemical stability of acetylsalicylic acid was evaluated as a model system of drug–excipient compatibility studies using ASAP. In the acetylsalicylic acid powder blends, temperature and humidity showed a first-order linear response to the natural logarithm of the reaction rate constant, and MgSt content also showed a first-order linear response. A polynomial model was built in which temperature, humidity, and MgSt content were independent each other. The fitting index of the model, the coefficient of determination, was 0.9567, which was a good fit. In the long-term stability study (25 °C/60% relative humidity, 6 months), there was good agreement in total between measured values and model-predicted values. Using this model, we inferred that the degradation rates were depended on MgSt content at the fixed temperature and humidity because the micro-environmental pH of the excipient was catalytically affected. Applying this model equation can significantly reduce the duration of formulation design and stability studies and save time and costs in drug development.
In clinical practice, a thickening solution is frequently used to allow easy swallowing of tablets by patients suffering from dysphagia. This study investigated the effect of the thickening solution on tablet disintegration. Model tablets containing different disintegrants were prepared and their disintegration times (DTs) measured using standard methods. We also performed an additional disintegration test on the model tablets after immersing them for 1 min in thickening solution containing xanthan gum (XTG-SOL) (“modified disintegration test”). The DTs of the test tablets were substantially prolonged by immersion in XTG-SOL. Furthermore, the effect of the XTG-SOL on the DTs differed depending on the type of disintegrant contained in the tablets. To investigate in more detail this prolongation of tablet disintegration, we examined the contribution of tablet properties to their DTs. The properties analyzed included contact angle, T2 relaxation time, wetting time, and water absorption ratio. The contributions of these properties to the DTs were analyzed using multiple regression analysis. This analysis clarified that the tablet properties affecting DTs changed after immersion in XTG-SOL: wetting time significantly affected the DTs measured in the normal disintegration test, while T2 was crucial for the DTs of tablets immersed in XTG-SOL. These findings provide valuable information for design of tablet formulations, and for clinical medication management for older patients with dysphagia.
clinical practice, a thickening solution is frequently used to allow easy
swallowing of tablets as well as foods by patients suffering from dysphagia. This
investigated the effect of thickening solution on tablet disintegration. Model tablets
containing different disintegrants were prepared and their disintegration times
were measured. The tablet disintegration times were
significantly prolonged by immersion in thickening
solution containing xanthan gum and the degree of prolongation differed depending on
the type of disintegrant
contained in the tablets. These findings provide valuable information for
design of tablet formulation and clinical medication
management for older patients with dysphagia.
Ceftiofur (CEF) is a third-generation and the first animal-specific cephalosporin that is widely used in animal husbandry. As a heat-labile antibiotic, the cytotoxicity of CEF after thermal treatment has been reported. This study seeks to investigate the potential toxicity of thermally treated CEF (TTC) in vivo based on acute oral toxicity studies and acute intraperitoneal studies in mice. Our data indicated that TTC exhibited significant increased toxicity in mice compared with CEF. TTC resulted in weight gain, hypercholesterolemia, hepatocyte steatosis and hepatocyte mitochondrial damage, and downregulated β-oxidation-related genes in mice in acute oral toxicity studies. In addition, TTC caused acute pulmonary congestion, increased levels of reactive oxygen species (ROS), prolonged coagulation time, and even death in mice in acute intraperitoneal toxicity studies. Our data showed that thermal treatment enhanced the toxicity of CEF in vivo. Lung and liver are the main target organs in the pathological damage process mediated by TTC. These findings suggested that residual CEF in animal-derived food may represent a potential food safety risk and pose a potential threat to human health.
Ophthalmic preservatives are indispensable in eye drop formulations, but may be toxic to corneal structures. Corneal damage necessitates the discontinuation of treatment with ophthalmic solutions. Therefore, the development of a new and safe preservative system without corneal toxicity is needed. The present study investigated the effects of mannitol on the antimicrobial activities and corneal toxicities of various preservatives using Escherichia coli and a human corneal epithelial cell line (HCE-T cells). The following preservatives were examined: boric acid (BA), benzalkonium chloride (BAC), methyl parahydroxybenzoate (MP), propyl parahydroxybenzoate (PP), sodium chlorite (SC), and zinc chloride (ZC). The antimicrobial activities and HCE-T-cell toxicities of 50 µg/mL BA, MP, PP, SC, and ZC were reduced by a co-treatment with mannitol (0–300 µg/mL). The suppressed antimicrobial activities of BA, MP, PP, and SC by the co-treatment with mannitol were restored by the application of a mannitol content higher than 500 µg/mL. In contrast to these 5 preservatives, the addition of mannitol did not affect the antimicrobial activity of BAC and attenuated its HCE-T cell toxicity. Therefore, the balance between the contents of mannitol and preservatives is important in co-treatments. The present results will serve as a guide for the future development of eye drop formulations without corneal toxicity.
Fragment-based approach combined with electrophilic reactive compounds is a powerful strategy to discover novel covalent ligands for protein target. However, the promiscuous reactivity often interferes with identification of the fragments possessing specific binding affinity to the targeted protein. In our study, we report the fragment-based covalent drug discovery using the chemically tuned weak reactivity of chlorofluoroacetamide (CFA). We constructed a small fragment library composed of 30 CFA-appended compounds and applied it to the covalent ligand screening for cysteine protease papain as a model protein target. Using the fluorescence enzymatic assay, we identified CFA-benzothiazole 30 as a papain inhibitor, which was found to irreversibly inactivate papain upon enzyme kinetic analysis. The formation of the covalent papain-30 adduct was confirmed using electrospray ionization mass spectrometry analysis. The activity-based protein profiling (ABPP) experiment using an alkynylated analog of 30 (i.e., 30-yne) revealed that 30-yne covalently labeled papain with high selectivity. These data demonstrate potential utility of the CFA-fragment library for de novo discovery of target selective covalent inhibitors.
Chlorofluoroacetamide (CFA) shows
chemically tuned mild reactivity that is suitable as an electrophilic warhead
for highly target selective covalent inhibitors. Assembly of a small set of
CFA-appended fragment library and its screening against cysteine protease
papain demonstrated the potential utility of CFA in novel covalent drug
discovery using a fragment-based approach.
A series of 2-(N-cyclicamino)chromone derivatives (1a–4c) and 3-(N-cyclicamino)chromone derivatives (5a–8c) were synthesized, and their monoamine oxidase (MAO) A and B inhibitory activities were studied as part of a structure–activity relationship investigation. Compounds 1a–4c showed no remarkable inhibition for MAO-A or MAO-B, whereas compounds 5a–8c (with a few exceptions) showed significant and selective inhibition of MAO-B. Of these compounds, 7c, 7-methoxy-3-(4-phenyl-1-piperazinyl)-4H-1-benzopyran-4-one inhibited MAO-B the most potently and selectively, having IC50 of 15 nM and an MAO-B selectivity index of more than 6700; c.f, 50 nM and 2000, respectively, for safinamide. The mode of inhibition of 7c to MAO-B was competitive and reversible. Considering the IC50 values and selectivity indices of the other synthetic compounds, the presence of the methoxy group on the chromone ring (R2) of 7c seemed to increase MAO-B inhibition. Molecular docking analysis also supports this hypothesis. Our results suggest that 3-(N-cyclicamino)chromones are useful lead compounds for the development of MAO-B inhibitors.
Extensive phytochemical work on the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Symplocos cochinchinensis var. philippinensis resulted in the isolation of 14 new triterpenene saponins, along with four known ones. Their structures were elucidated by comparison of NMR spectroscopic data with related compounds reported in the literature. Three oleanane-type saponins, symplocosins K, M, and P, possessed glucuronic acid as a sugar component, and their carboxyl groups appeared as methyl esters. These are probably formed during extraction and isolation procedures. Symplocosin K (9) showed moderate cytotoxicity toward A549 cells. In addition, all isolated compounds did not show α-glucosidase inhibitory activity.
α,β-Unsaturated esters were selectively protected in situ in the presence of α,β-unsaturated Weinreb amides using PEt3 and trimethylsilyl trifluoromethanesulfonate (TMSOTf) in toluene under reflux. Diisobutylaluminium hydride (DIBAL-H) reduction of the mixture followed by tetra-n-butylammonium fluoride (TBAF) treatment produced α,β-unsaturated aldehydes in good yields along with the recovered α,β-unsaturated esters.
Catalytic dearomative transformations of phenol variants via an ipso-Friedel-Crafts reaction could provide a straightforward method for the rapid assembly of functionalized spiromolecules as versatile synthetic scaffolds. We previously reported a dearomative spirocyclization reaction by merging Brønsted acid and hydrogen-bonding catalysis. However, it was unclear how the reaction proceeded and how the synergic effect was triggered. Described herein are the computational studies used to elucidate the reaction mechanism. Such calculations indicated that the applied catalysts, maleic acid and Schreiner’s thiourea, work cooperatively. The synergic effect enabled the chemoselectivity to interconvert between phenol dearomatization and O–H insertion, which is a major side reaction. This investigation also revealed that not only does the Schreiner’s thiourea catalyst serve as a hydrogen bonding donor, but the sulfur atom in thiourea possesses a general base function. The dual functional support of the thiourea along with maleic acid would thus realize the chemoselective prioritization of dearomatization over the O–H insertion reaction under mild conditions.
The occurrence of complex coacervation in an aqueous mixture of proteins (lysozyme, albumin, immunoglobulin G) and hyaluronic acid and its effect on protein transition in a model system was studied to elucidate factors determining the bioavailability of subcutaneously injected therapeutic proteins. Mixing of hyaluronic acid and the model proteins induced complex coacervation at solution pH close to or below the isoelectric point of the proteins. In vitro dialysis using membranes with large pore size tube represented a limitation in the protein transition of the coacervation mixture. Thermal analysis suggested there was retention of the protein conformation in the polymer complex.
Three O-methyl anthocyanidin 3-O-β-D-glucopyranosides were isolated from bilberry extract on a large-scale basis together with two non O-methyl analogues. Anthocyanidin 3-O-β-D-galactopyranosides were removed from bilberry extract together with parts of anthocyanidin 3-O-α-L-arabinopyranosides after treatment with β-galactosidase. The remaining arabinopyranosides were removed by applying acid catalytic hydrolysis. The amounts of anthocyanins recovered as flavylium trifluoroacetic acid salt were as follows: 630 mg for petunidin 3-O-β-D-glucopyranoside, 423 mg for peonidin 3-O-β-D-glucopyranoside, 588 mg for malvidin 3-O-β-D-glucopyranoside, 877 mg for delphinidin 3-O-β-D-glucopyranoside, and 742 mg for cyanidin 3-O-β-D-glucopyranoside.
Zerumbone is a multifunctional compound which shows various biological activities, such as antitumor activity, anti-inflammatory activity, antiulcer activity, etc. However, to use Zerumbone as functional foods or medicines, its pharmaceutical properties such as solubility should be improved. In the present study, we prepared its inclusion complexes with various cyclodextrin (CyD) derivatives, and evaluated their solubility, release profile of the drug and cytotoxic activity. Among 11 CyDs, sulfobutylether (SBE)-β-CyD showed the highest solubilizing effect for Zerumbone. Phase solubility diagrams of SBE-β-CyD/Zerumbone in 10% methanol solution showed AL type, and the stability constant was 756 M−1. SBE-β-CyD also formed the solid complex with Zerumbone by kneading for 90 min. Importantly, the dissolution rate of Zerumbone was improved by complexation with SBE-β- and hydroxypropyl (HP)-β-CyDs, and its supersaturation was maintained for several hours. The solubilizing effects by SBE-β-CyD was greater than that of HP-β-CyD. Moreover, SBE-β-CyD/Zerumbone complex also retained the cytotoxic activity of Zerumbone. These results suggest that CyDs, especially SBE-β-CyD, were useful to improve the solubility of Zerumbone.