Comparison and Determination of the Content of Mosapride Citrate by Different qNMR Methods.

As a salt-type compound, mosapride citrate's metabolism and side effects are correlated with its salt-forming ratio. Several techniques were developed in this work to compare various quantitative nuclear magnetic resonance (qNMR) methodologies and to quantitatively examine the content of raw materials. Among the qNMR techniques, methods for 1H NMR and 19F NMR were developed. Appropriate solvents were chosen, and temperature, number of scans, acquisition time, and relaxation delay parameter settings were optimized. Maleic acid was chosen as the internal standard in 1H NMR, and the respective characteristic signals of mosapride and citrate were selected as quantitative peaks. The internal standard in 19F NMR analysis was 4,4'-difluoro diphenylmethanone, and the distinctive signal peak at -116.15 ppm was utilized to quantify mosapride citrate. The precision, repeatability, linearity, stability, accuracy, and robustness of the qNMR methods were all validated according to the ICH guidelines. By contrasting the outcomes with those from high-performance liquid chromatography (HPLC), the accuracy of qNMR was assessed. As a result, we created a quicker and easier qNMR approach to measure the amount of mosapride citrate and evaluated several qNMR techniques to establish a foundation for choosing quantitative peaks for the qNMR method. Concurrently, it is anticipated that various selections of distinct quantitative objects will yield the mosapride citrate salt-forming ratio.

Economical and rapid enantioselective, diastereoselective and achiral separation of palonosetron hydrochloride and its impurities using supercritical fluid chromatography.

Simultaneous separation of compounds with multiple chiral centers and highly similar structures presents significant challenges. This study developed a novel supercritical fluid chromatography (SFC) method with reduced organic solvent consumption and robust separation capabilities to address these challenges. The method was applied to simultaneously achieve enantioselective, diastereoselective, and achiral separation of palonosetron hydrochloride and its six impurities. The effects of the polysaccharide-based chiral stationary phase (CSP), modifier, additive, and column temperature on retention and separation were comprehensively evaluated. It was found that a combination of a polysaccharide-based CSP and a single modifier or a mixture of protonic modifiers could not achieve complete separation due to high structural similarity. However, an ADH column and a ternary solvent mixture containing acetonitrile (methanol: acetonitrile: diethylamine, 60:40:0.2, v/v/v) provided satisfying separation, particularly for the enantiomer and diastereomers of palonosetron. Using the optimized method, the enantioselective, diastereoselective, and achiral separation of palonosetron hydrochloride and its six impurities can be accomplished in 18 min under gradient elution. Thermodynamic results indicated that the separation process was entropy driven. A molecular docking study revealed that the separation was mainly achieved through the differences in hydrogen bond and π - π interactions between the analytes and CSP. This study lays the foundation for SFC analysis of palonosetron hydrochloride and provides a reference for the simultaneous SFC separation of the enantiomers, diastereoisomers and structurally similar compounds.

Preparation and optimization of dummy molecularly imprinted polymer-based solid-phase extraction system for selective enrichment of p-toluene sulfonate esters genotoxic impurities.

Sulfonate esters, one class of genotoxic impurities (GTIs), have gained significant attention in recent years due to their potential to cause genetic mutations and cancer. In the current study, we employed the dummy template molecular imprinting technology with a dummy template molecule replacing the target molecule to establish a pretreatment method for samples containing p-toluene sulfonate esters. Through computer simulation and ultraviolet-visible spectroscopy analysis, the optimal functional monomer acrylamide and polymerization solvent chloroform were selected. Subsequently, a dummy template molecularly imprinted polymer (DMIP) was prepared by the precipitation polymerization method, and the polymer was characterized in morphology, particle size, and composition. The results of the adsorption and enrichment study demonstrated that the DMIP has high adsorption capability (Q = 7.88 mg/g) and favorable imprinting effects (IF = 1.37); Further, it could simultaneously adsorb three p-toluene sulfonate esters. The optimal adsorption conditions were obtained by conditional optimization of solid-phase extraction (SPE). A pH 7 solution was selected as the loading condition, the methanol/1 % phosphoric acid solution (20:80, v/v) was selected as the washing solution, and acetonitrile containing 10 % acetic acid in 6 mL was selected as the elution solvent. Finally, we determined methyl p-toluene sulfonate alkyl esters, ethyl p-toluene sulfonate alkyl esters, and isopropyl p-toluene sulfonate alkyl esters in tosufloxacin toluene sulfonate and capecitabine at the 10 ppm level (relative to 1 mg/mL active pharmaceutical ingredient (API) samples) by using DMIP-based SPE coupled with HPLC. This approach facilitated the selective enrichment of p-toluene sulfonate esters GTIs from complex API samples.

A cell-based assay to discover inhibitors of Zika virus RNA-dependent RNA polymerase.

Zika virus (ZIKV) belongs to Flaviviridae, the Flavivirus genus. Its infection causes congenital brain abnormalities and Guillain-Barré syndrome. However, there are no effective vaccines, no FDA-approved drugs to manage ZIKV infection. The non-structural protein NS5 of ZIKV has been recognized as a valuable target of antivirals because of its RNA-dependent RNA polymerase (RdRp) and methyltransferase (MTase) activities essential for viral RNA synthesis. Here, we report a cell-based assay for discovering inhibitors of ZIKV NS5 and found that 5-Azacytidine potently inhibits ZIKV NS5, with EC50 of 4.9 µM. Furthermore, 5-Azacytidine suppresses ZIKV replication by inhibiting NS5-mediated viral RNA transcription. Therefore, we have developed a cell-based ZIKV NS5 assay which can be deployed to discover ZIKV NS5 inhibitors and demonstrated the potential of 5-Azacytidine for further development as a ZIKV NS5 inhibitor.

A novel multi-hyphenated approach to screen and character the xanthine oxidase inhibitors from saffron floral bio-residues.

Recently, the incidence of hyperuricemia increased with patient rejuvenation, searching for new xanthine oxidase (XOD) inhibitors from natural products becomes important. In our previous work, a flavonoid extract of saffron floral bio-residues (SFB) was found to alleviate hyperuricemia via inhibiting XOD. In this study, an integrated approach combining two-dimensional liquid chromatography, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) was developed to online screen and character the potential XOD inhibitors from SFB. The two-dimensional liquid chromatography consisted of affinity chromatography and reverse phase chromatography (2D-AR), in which an XOD column, an inactive XOD column, and a control column were used in the first dimensional liquid chromatography to avoid phenomena of "false positive" and "missing screen of compounds with weak affinity to XOD" that often occur in the screening process, and a C18 column was used in the second dimensional liquid chromatography to separate the mixed XOD binders. Four flavonoid glycosides, i.e., quercetin-3-O-sophoroside (QS), kaempferol-3-O-sophoroside (KS), kaempferol-3-O-rutinoside (KR), and kaempferol-3-O-glucoside (KG), were thus successfully screened and identified from SFB extract by the 2D-AR method. The affinity of QS, KS, KR, KG, kaempferol (aglycone of KS, KR and KG), and quercetin (aglycone of QS) binding to XOD was investigated using SPR method, with KD ranged from 4.8 µM to 47.6 µM. The inhibitor constant (KI) of KS, KR, KG, quercetin and kaempferol were 4.92 mM, 1.11 mM, 0.294 mM, 4.93 µM and 3.27 µM, respectively, determined using ITC method. Finally, the anti-XOD activities of KS, the most abundant flavonoid in SFB extract, and kaempferol in hyperuricemia mice were verified, which suggested that the multi-hyphenated approach established herein can be applied for screen and character the XOD inhibitors in natural products.

Teicoplanin derivatives block spike protein mediated viral entry as pan-SARS-CoV-2 inhibitors.

The rapid emergence of highly transmissible SARS-CoV-2 variants poses serious threat to the efficacy of vaccines and neutralizing antibodies. Thus, there is an urgent need to develop new and effective inhibitors against SARS-CoV-2 and future outbreaks. Here, we have identified a series of glycopeptide antibiotics teicoplanin derivatives that bind to the SARS-CoV-2 spike (S) protein, interrupt its interaction with ACE2 receptor and selectively inhibit viral entry mediated by S protein. Computation modeling predicts that these compounds interact with the residues in the receptor binding domain. More importantly, these teicoplanin derivatives inhibit the entry of both pseudotyped SARS-CoV-2 Delta and Omicron variants. Our study demonstrates the feasibility of developing small molecule entry inhibitors by targeting the interaction of viral S protein and ACE2. Together, considering the proven safety and pharmacokinetics of teicoplanin as a glycopeptide antibiotic, the teicoplanin derivatives hold great promise of being repurposed as pan-SARS-CoV-2 inhibitors.

Halogenase-Targeted Genome Mining Leads to the Discovery of (±) Pestalachlorides A1a, A2a, and Their Atropisomers.

Genome mining has become an important tool for discovering new natural products and identifying the cryptic biosynthesis gene clusters. Here, we utilized the flavin-dependent halogenase GedL as the probe in combination with characteristic halogen isotope patterns to mine new halogenated secondary metabolites from our in-house fungal database. As a result, two pairs of atropisomers, pestalachlorides A1a (1a)/A1b (1b) and A2a (2a)/A2b (2b), along with known compounds pestalachloride A (3) and SB87-H (4), were identified from Pestalotiopsis rhododendri LF-19-12. A plausible biosynthetic assembly line for pestalachlorides involving a putative free-standing phenol flavin-dependent halogenase was proposed based on bioinformatics analysis. Pestalachlorides exhibited antibacterial activity against sensitive and drug-resistant S. aureus and E. faecium with MIC values ranging from 4 µg/mL to 32 µg/mL. This study indicates that halogenase-targeted genome mining is an efficient strategy for discovering halogenated compounds and their corresponding halogenases.

Repurposing of the antihistamine mebhydrolin napadisylate for treatment of Zika virus infection.

Zika virus (ZIKV) infection can lead to severe neurological disorders and fetal defects, which has become a public health problem worldwide. However, effective clinical treatment for ZIKV infection was still arduous. Antihistamines are attractive candidates for drug repurposing due to their low price and widespread availability. Here we screened FDA-approved antihistamine drugs to obtain anti-ZIKV candidate compounds and identified mebhydrolin napadisylate (MHL) that exhibits the potent inhibition of ZIKV infection in various cell lines in a histamine H1 receptor-independent manner. Mechanistic studies suggest that MHL acts as a ZIKV NS5 RNA-dependent RNA polymerase (RdRp) inhibitor, supported by a structure-activity relationship (SAR) analysis showing the correlation between the inhibitory effect upon viral RNA synthesis and ZIKV infectivity. Furthermore, MHL was shown to bind ZIKV NS5 RdRp in vitro and predicted to interact with key residues at the active site of ZIKV NS5 RdRp by molecular docking analysis. Our data together suggest that MHL suppresses ZIKV infection through the inhibition of ZIKV NS5 RdRp activity. This study highlights that MHL might be a promising clinical anti-ZIKV therapeutic.

Application of Transmission Raman Spectroscopy in Combination with Partial Least-Squares (PLS) for the Fast Quantification of Paracetamol.

In recent years, transmission Raman spectroscopy (TRS) has emerged as a potent new tool for rapid, nondestructive quantitation in pharmaceutical manufacturing. In order to expand the applicability of TRS and enhance its use in product quality monitoring during drug production, we aimed, in the present study, to apply partial least-squares (PLS) approaches to build a model consisting of 150 handmade tablets and covering 15 levels through the use of a multifactor orthogonal design of experiment (DOE), which was used to predict concentrations of validation tablets made by hand. The difference between results according to HPLC and TRS were negligible. The model was used to predict the active pharmaceutical ingredient (API) content in four random commercial paracetamol tablets, and corrected with the spectra of the commercial tablets to obtain four corresponding models. The results show that the content relative error in the model's predictions after correction with commercially available tablets was significantly lower than that before correction. The corrected model was used to make predictions for 20 tablets from the brand Panadol. Compared with the HPLC results, the prediction relative error was basically less than 4.00%, and the relative standard deviation (RSD) of the content was 0.86%.

A DasA family sugar binding protein Ste2 links nutrient and oxidative stress to exopolysaccharides production in Streptomyces sp. 139.

BACKGROUND: Ebosin is an exopolysaccharide produced by Streptomyces sp. 139, and its biosynthetic gene cluster (ste) has been previously described. Ste234 has high homology to the well-known ATP-binding cassette transport system DasABC, which has been linked to the regulation of morphological differentiation, antibiotics biosynthesis and aminosugars utilization in Streptomycetes. This study was conducted to evaluate the effect of the DasA family sugar binding protein Ste2 on Streptomyces sp. 139. RESULTS: The disruption of ste2 results in the upregulation of transcription of genes within Ebosin biosynthetic gene cluster and a two-fold increase in Ebosin production. RNA sequencing data suggests that the disruption of ste2 results in the decreased utilization of carbon and nitrogen sources, increased sensitivity to oxidative stress, as well as differed strain morphology, all of which have been experimentally proven. CONCLUSIONS: Taken together, Ste2 controls Ebosin yields, aminosugars uptake, sensitivity to oxidative stress, and morphological differentiation of Streptomyces sp. 139.

Separation of chiral and achiral impurities in paroxetine hydrochloride in a single run using supercritical fluid chromatography with a polysaccharide stationary phase.

Separating paroxetine hydrochloride and its impurities using conventional reversed-phase liquid chromatography (RPLC) is challenging due to their highly similar structures. In the present study, a rapid, simple, sensitive and environmentally friendly method was developed for the determination of chiral and achiral impurities in raw materials of paroxetine hydrochloride using chiral supercritical fluid chromatography (SFC). The impacts of chiral stationary phases (CSPs), mobile phases, column temperature and back pressure on the retention and separation of analytes were comprehensively evaluated. After method optimization, a satisfying result was obtained on a cellulose tris-(3-chloro-4-methylphenylcarbamate) stationary phase in 4.0 min using 70% CO2 and 20 mM ammonium acetate in 30% methanol as the mobile phase. Molecular docking was further performed to understand the interactions between the analytes and CSP. The results suggested that hydrogen bonding and π-π interactions were the dominant interactions. The affinity given by the software was in good agreement with the elution order and free energy (△G) values obtained from van't Hoff equations. The results of molecular docking also provide insights into the different retentions of N-methylparoxetine at different temperatures. The results of method validation revealed that the method was sensitive with a limit of detection of approximately 0.05 µg·mL-1 (corresponding to approximately 0.005% paroxetine hydrochloride in the sample solution). The relative standard deviations (RSDs) of precision and intra-assay precision were all less than 2.0%, and the recoveries of the method were 93.8~105.3% with RSDs less than 3.0%. The chiral and achiral RPLC methods included in the Chinese pharmacopoeia and the SFC method proposed in this study were simultaneously used to determine the impurity content in the raw materials of paroxetine hydrochloride. The results showed that impurities that cannot be detected by the reference method can be accurately quantified using the SFC method. In addition, the SFC method has advantages in terms of throughput, analysis cost and simplicity. This study can provide a reference for further research of impurities in paroxetine hydrochloride and promote the application of chiral SFC in the rapid separation of structurally similar compounds.

Identification of miRNA and Their Regulatory Effects Induced by Total Flavonoids From Dracocephalum moldavica in the Treatment of Vascular Dementia.

Vascular dementia (VaD) is a general term used to describe difficulties in memory, reasoning, judgment, and planning caused by a reduced blood flow to the brain and consequent brain damage, in which microRNAs (miRNAs) are involved. Dracocephalum moldavica L. (D. moldavica) is traditionally used in the treatment of cardiovascular diseases as well as VaD, but the biomolecular mechanisms underlying its therapeutic effect are obscure. In the present study, the molecular mechanisms involved in the treatment of VaD by the total flavonoids from Dracocephalum moldavica L. (TFDM) were explored by the identification of miRNA profiling using bioinformatics analysis and experimental verification. A total of 2,562 differentially expressed miRNAs (DEMs) and 3,522 differentially expressed genes (DEGs) were obtained from the GSE120584 and GSE122063 datasets, in which the gene functional enrichment and protein-protein interaction network of 93 core targets, originated from the intersection of the top DEM target genes and DEGs, were established for VaD gene profiling. One hundred and eighty-five targets interacting with 42 flavonoids in the TFDM were included in a compound-target network, subsequently found that they overlapped with potential targets for VaD. These 43 targets could be considered in the treatment of VaD by TFDM, and included CaMKII, MAPK, MAPT, PI3K, and KDR, closely associated with the vascular protective effect of TFDM, as well as anti-oxidative, anti-inflammatory, and anti-apoptotic properties. The subsequent analysis of the compound-target gene-miRNA network indicated that eight miRNAs that mediated 43 targets had a close interaction with TFDM, suggesting that the neuroprotective effects were principally due to kaempferol, apigenin, luteolin, and quercetin, which were mostly associated with the miR-3184-3p/ESR1, miR-6762-3p/CDK1, miR-6777-3p/ESRRA, and other related axes. Furthermore, the in vitro oxygen-glucose deprivation (OGD) model demonstrated that the dysregulation of miR-3184-3p and miR-6875-5p found by qRT-PCR was consistent with the changes in the bioinformatics analysis. TFDM and its active compounds involving tilianin, luteolin, and apigenin showed significant effects on the upregulation of miR-3184-3p and downregulation of miR-6875-5p in OGD-injured cells, in line with the improved cell viability. In conclusion, our findings revealed the underlying miRNA-target gene network and potential targets of TFDM in the treatment of VaD.

Impurity profiling of Compound Amino Acid Injection (6AA) using ion-pair high performance liquid chromatography coupled with corona-charged aerosol detection and high resolution mass spectrometry.

The complex industrial production process of amino acids (AAs) leads to the existence of a certain amount of impurities in Compound Amino Acid Injection (6AA). It is difficult to obtain its comprehensive and systematic impurity profile using conventional ultraviolet (UV) detectors due to lack of a suitable chromophore in the structures of AAs and their impurities. In our study, a universal ion-pair high performance liquid chromatography (HPLC) method combined with high resolution mass spectrometer (HRMS) and charged aerosol detection (CAD) was developed to identify and determine the content of impurities in Compound Amino Acid Injection (6AA), respectively. After optimizing the content of trifluoroacetic acid (TFA) and heptafluorobutyric acid (HFBA) in the mobile phase on a C18 AQ column, HPLC-CAD method was developed and nine unknown impurities were detected. These impurities were successfully identified using HPLC coupled with orbitrap mass spectrometry and confirmed with their reference substances. The CAD parameters setting was optimized to improve the sensitivity and linearity of the methods before the developed method was validated. The results of validation reflected that the limit of detection (LOD) was approximately 2 ng (corresponding to approximately 0.02 % of L-isoleucine in injection). Under the optimized power function value (PFV) of CAD, the linear range of each impurity was 1 ∼ 200 µg mL-1 (the linear range of one of the impurities with higher content was 2 ∼ 400 µg mL-1) with coefficients of determination (R2) greater than 0.998. The recovery rates for nine impurities were 93.37 % ∼ 110.23 %. This study made full use of the qualitative functions of HRMS and the versatility of CAD, revealing possible impurities in the 6AA injection, which could provide reference for the safety research of it.

Recent advances in research of colchicine binding site inhibitors and their interaction modes with tubulin.

Microtubules have been a concerning target of cancer chemotherapeutics for decades, and several tubulin-targeted agents, such as paclitaxel, vincristine and vinorelbine, have been approved. The colchicine binding site is one of the primary targets on microtubules and possesses advantages compared with other tubulin-targeted agents, such as inhibitors of tumor vessels and overcoming P-glycoprotein overexpression-mediated multidrug resistance. This study reviews and summarizes colchicine binding site inhibitors reported in recent years with structural studies via the crystal structures of complexes or computer simulations to discover new lead compounds. We are attempting to resolve the challenge of colchicine site agent research.

Blocking Effect of Demethylzeylasteral on the Interaction between Human ACE2 Protein and SARS-CoV-2 RBD Protein Discovered Using SPR Technology.

The novel coronavirus disease (2019-nCoV) has been affecting global health since the end of 2019, and there is no sign that the epidemic is abating. Targeting the interaction between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and the human angiotensin-converting enzyme 2 (ACE2) receptor is a promising therapeutic strategy. In this study, surface plasmon resonance (SPR) was used as the primary method to screen a library of 960 compounds. A compound 02B05 (demethylzeylasteral, CAS number: 107316-88-1) that had high affinities for S-RBD and ACE2 was discovered, and binding affinities (KD, µM) of 02B05-ACE2 and 02B05-S-RBD were 1.736 and 1.039 µM, respectively. The results of a competition experiment showed that 02B05 could effectively block the binding of S-RBD to ACE2 protein. Furthermore, pseudovirus infection assay revealed that 02B05 could inhibit entry of SARS-CoV-2 pseudovirus into 293T cells to a certain extent at nontoxic concentration. The compoundobtained in this study serve as references for the design of drugs which have potential in the treatment of COVID-19 and can thus accelerate the process of developing effective drugs to treat SARS-CoV-2 infections.

Discovery of indolyl-containing peptides as novel antibacterial agents targeting tryptophanyl-tRNA synthetase.

Background: There is an urgent need for antibiotics with novel structures and unexploited targets to counteract bacterial resistance. Methodology & results: Novel tryptophanyl-tRNA synthetase inhibitors were discovered based on virtual screening, surface plasmon resonance binding, enzymatic activity assay and antibacterial activity evaluation. Of the 29 peptide derivatives tested for antibacterial activity, some inhibited the growth of both Staphylococcus aureus and Staphylococcus epidermidis. A13 and A15 exhibited antibacterial activity against methicillin-resistant S. aureus NRS384 at an 8 µg/ml minimum inhibitory concentration. A13 snugly docked into the active site, explaining its improved inhibitory activity. Conclusion: Our results provide us with new structural clues to develop more potent tryptophanyl-tRNA synthetase inhibitors and lay a solid foundation for future drug design efforts.

A self-assembled electrochemical immunosensor for ultra-sensitive detection of ochratoxin A in medicinal and edible malt.

Trace residue of mycotoxins in complex medicinal and edible food matrices has brought huge challenges for the development of ultrasensitive analytical methods. Here, a green electrochemical immunosensor for the ultrasensitive detection of ochratoxin A (OTA) was fabricated by self-assembling a compact 2-mercaptoacetic (TGA) monolayer on the surface of the working Au electrode to form the Au/TGA/bovine serum aibumin (BSA)-OTA/anti-OTA monoclonal antibody composite probes for selective and ultra-sensitive detection of OTA based on indirect competitive principle and differential pulse voltammetry analysis. The electrochemical impedance spectroscopy and cyclic voltammetry methods were introduced to characterize the assemble situation of the TGA-modified Au electrode and optimize some critical parameters for the green electrochemical immunoseonsor. Under the optimal conditions, the developed immunosensor exhibited much lower limit of detection (0.08 ng/mL) in the range of 0.1-1.0 ng/mL for OTA compared with other direct or disposable electrochemical immunosensors. Real application in the spiked malt samples verified high accuracy with no matrix interferences of the proposed immunoseonsor. This is a meaningful study on a self-assembled electrochemical immunoseonsor for ultra-sensitive and rapid detection of OTA in malt samples, which suggested a general simple-to-use sensing platform and prospect as an economical and green tool for ultra-sensitive detection of much more trace-level of toxic small molecules in other complex matrices to ensure their quality and safety.

Five solvates of a multicomponent pharmaceutical salt formed by berberine and diclofenac.

A multicomponent pharmaceutical salt formed by the isoquinoline alkaloid berberine (5,6-dihydro-9,10-dimethoxybenzo[g]-1,3-benzodioxolo[5,6-a]quinolizinium, BBR) and the nonsteroidal anti-inflammatory drug diclofenac {2-[2-(2,6-dichloroanilino)phenyl]acetic acid, DIC} was discovered. Five solvates of the pharmaceutical salt form were obtained by solid-form screening. These five multicomponent solvates are the dihydrate (BBR-DIC·2H2O or C20H18NO4+·C14H10Cl2NO2-·2H2O), the dichloromethane hemisolvate dihydrate (BBR-DIC·0.5CH2Cl2·2H2O or C20H18NO4+·C14H10Cl2NO2-·0.5CH2Cl2·2H2O), the ethanol monosolvate (BBR-DIC·C2H5OH or C20H18NO4+·C14H10Cl2NO2-·C2H5OH), the methanol monosolvate (BBR-DIC·CH3OH or C20H18NO4+·C14H10Cl2NO2-·CH3OH) and the methanol disolvate (BBR-DIC·2CH3OH or C20H18NO4+·C14H10Cl2NO2-·2CH3OH), and their crystal structures were determined. All five solvates of BBR-DIC (1:1 molar ratio) were crystallized from different organic solvents. Solvent molecules in a pharmaceutical salt are essential components for the formation of crystalline structures and stabilization of the crystal lattices. These solvates have strong intermolecular O...H hydrogen bonds between the DIC anions and solvent molecules. The intermolecular hydrogen-bond interactions were visualized by two-dimensional fingerprint plots. All the multicomponent solvates contained intramolecular N-H...O hydrogen bonds. Various π-π interactions dominate the packing structures of the solvates.

Polygala tenuifolia-Acori tatarinowii herbal pair as an inspiration for substituted cinnamic α-asaronol esters: Design, synthesis, anticonvulsant activity, and inhibition of lactate dehydrogenase study.

Inspired by the traditional Chinese herbal pair of Polygala tenuifolia-Acori Tatarinowii for treating epilepsy, 33 novel substituted cinnamic α-asaronol esters and analogues were designed by Combination of Traditional Chinese Medicine Molecular Chemistry (CTCMMC) strategy, synthesized and tested systematically not only for anticonvulsant activity in three mouse models but also for LDH inhibitory activity. Thereinto, 68-70 and 75 displayed excellent and broad spectra of anticonvulsant activities with modest ability in preventing neuropathic pain, as well as low neurotoxicity. The protective indices of these four compounds compared favorably with stiripentol, lacosamide, carbamazepine and valproic acid. 68-70 exhibited good LDH1 and LDH5 inhibitory activities with noncompetitive inhibition type, and were more potent than stiripentol. Notably, 70, as a representative agent, was also shown as a moderately positive allosteric modulator at human α1ß2γ2 GABAA receptors (EC50 46.3 ±â€¯7.3 µM). Thus, 68-70 were promising candidates for developing into anti-epileptic drugs, especially for treatment of refractory epilepsies such as Dravet syndrome.

Determination of epoxide impurity in sarpogrelate hydrochloride intermediate by UHPLC and column-switching liquid chromatography.

The determination of genotoxic impurities, which is closely related to toxicological concern and daily dose, plays a key role in drug quality control. Epoxide impurity is a kind of genotoxic impurity with an epoxy ring structure during the synthesis process of sarpogrelate hydrochloride. According to the sarpogrelate hydrochloride daily dose, epoxide impurity is limited to the under 5 ppm level. The liquid chromatographic-tandem mass spectrometric (LC/MS/MS) or the gas chromatography-mass spectrometric (GC/MS) method is commonly used to characterize the epoxide impurity of sarpogrelate hydrochloride intermediates. However, these methods are not simple or economical enough to detect epoxide impurity. In this study, we resolved the problem by using the most common UV method with two ideas: one was to improve the absolute sensitivity, and the other was to reduce matrix effects. Both ultra high-performance liquid chromatography (UHPLC with high sensitivity LightPipe™ flow cells) and column-switching liquid chromatography methods were developed and validated for the quantitative determination of epoxide impurity in sarpogrelate hydrochloride intermediates. The limits of detection (LODs) of the UHPLC and column-switching liquid chromatography methods were 0.09 ppm (0.09 µg/g) and 0.33 ppm (0.33 µg/g), and the recovery rates of both methods were 87.2%-132.1% and 97.4%-100.1%, respectively. Both methods established and provided guidance for analysts to develop procedures for impurity control, especially for structures of impurity with similar matrices.