Determination of the Handedness of Urea Inclusion Compounds.

Since the discovery of urea inclusion compounds (UICs) in 1940, the handedness of this chiral helical system has not been established experimentally. Here three UIC systems containing only light atoms were studied. The optical rotations were first measured, and the absolute structures of the enantiomorphic domains of three UICs were determined by single crystal X-ray diffraction (SCXRD). The correlation between the optical rotation and the absolute configuration of the UICs was finally established, showcasing the power of absolute structure determination by SCXRD, which is essential in structural chemistry and pharmaceutical research.

Determination of the Handedness of Urea Inclusion Compounds.

Invited for the cover of this issue is the group of Bo Wang at Biogen. The image depicts the sectored chiral domains of urea inclusion compounds. Read the full text of the article at 10.1002/chem.202302217.

The Effect of In-Situ-Generated Moisture on Disproportionation of Pharmaceutical Salt.

Pharmaceutical salts are ubiquitously present in the market given their benefits in optimizing the critical properties of an active pharmaceutical ingredient (API). Achieving these benefits requires careful selection and understanding of the salt form of choice. Stability is especially critical here, as salts are susceptible to disproportionation. Several studies have shown the impact of moisture on disproportionation, with more focus on external humidity (moisture coming from outside the system). This work, on the other hand, is systematically designed to study the impact of moisture generated in situ (moisture produced within the system). To that end, an in-house developed compound 1 was selected as our salt API, and its disproportionation was studied in blends (binary and prototype) with hydrated model excipient─trisodium phosphate dodecahydrate (TSPD). TSPD possesses 12 water molecules, which could get released when triggered with enough energy (confirmed by thermogravimetric analysis and humidity studies). As a control for this study, similar blends were prepared with anhydrous trisodium phosphate (TSP), which has comparable properties to TSPD but lacks water. Overall, significant disproportionation was observed in TSPD blends exposed to 40 °C or 70 °C in a closed system; while no disproportionation was observed when the system was left open due to the escape of the moisture generated in situ. The API also remained intact for the blends with anhydrous TSP, as expected. Meanwhile, stressing at 40 °C/75%RH condition resulted in significant disproportionation for both TSPD and TSP blends due to the exposure to external humidity. Hydrated excipients are normally used in drug development, and this work stresses the need for probing the impact from within the system when such excipients are utilized with salt API. This will help fully unravel the overall effect of moisture on the drug, which is relevant downstream when selecting processing conditions, packaging, and so forth.

Improving the Manufacturability of Cohesive and Poorly Compactable API for Direct Compression of Mini-tablets at High Drug Loading via Particle Engineering.

PURPOSE: To utilize a particle engineering strategy to improve the manufacturability of a cohesive and poorly compactable API at high drug loading for direct compression of mini-tablets. METHODS: A high-shear mixer was used for wet milling during the API manufacturing process to obtain target particle size distributions. The targeted particles were characterized and formulated into blends by mixing with excipients. The formulated blends were compressed directly into mini-tablets using a compaction simulator. The tablet hardness, weight variation, and friability of the mini-tablets were characterized and compared with mini-tablets prepared with hammer milled APIs. RESULTS: Compared to the hammer milled APIs, the wet milled APIs, had smoother surface, narrower particle size distributions and demonstrated a better flow properties. Moreover, the mini-tablets produced with the wet milled APIs exhibited better weight uniformity, robust tablet mechanical strength and ultimately better friability. In addition, unlike the hammer milled process, the wet milling process is controllable and easy to scale up. CONCLUSIONS: This study successfully implemented API particle engineering through a high shear wet milling process to produce particles suitable for robust drug product manufacturing.

Effects of different carbon sources on the removal of ciprofloxacin and pollutants by activated sludge: Mechanism and biodegradation.

This research investigated the effects of ciprofloxacin (CIP) (0.5, 5, and 20 mg/L) on SBR systems under different carbon source conditions. Microbial community abundance and structure were determined by quantitative PCR and high-throughput sequencing, respectively. The biodegradation production of CIP and possible degradation mechanism were also studied. Results showed that CIP had adverse effects on the nutrient removal from wastewater. Compared with sodium acetate, glucose could be more effectively used by microorganisms, thus eliminating the negative effects of CIP. Glucose stimulated the microbial abundance and increased the removal rate of CIP by 18%-24%. The mechanism research indicated that Proteobacteria and Acidobacteria had a high tolerance for CIP. With sodium acetate as a carbon source, the abundance of nitrite-oxidizing bacterial communities decreased under CIP, resulting in the accumulation of nitrite and nitrate. Rhodanobacter and Microbacterium played a major role in nitrification and denitrification when using sodium acetate and glucose as carbon sources. Dyella and Microbacterium played positive roles in the degradation process of CIP and eliminated the negative effect of CIP on SBR, which was consistent with the improved removal efficiency of pollutants.

Effects and possible mechanisms of sanguinarine on the competition between Raphidiopsis raciborskii (Cyanophyta) and Scenedesmus obliquus (Chlorophyta): A comparative toxicological study.

The phytogenic algicide sanguinarine shows strong inhibitory effects on some bloom-forming cyanobacteria and exhibits great potential in cyanobacterial bloom mitigation. To evaluate the possible ecological effects of sanguinarine on microalgae, the effects and possible mechanisms of sanguinarine on the competition between bloom-forming cyanobacterium Raphidiopsis raciborskii (formerly named Cylindrospermopsis raciborskii) and green alga Scenedesmus obliquus were investigated through co-culture competition test and comparative toxicological study including growth characteristics, chlorophyll fluorescence transients, activities of antioxidant enzymes, and lipid peroxidation. The results of Raphidiopsis-Scenedesmus co-culture competition test showed that sanguinarine decreased the competition ability of R. raciborskii, which benefitted S. obliquus in winning the competition. Toxicological studies have shown that sanguinarine exhibited high inhibitory effects on the growth and photosynthesis of R. raciborskii but no obvious toxicity on S. obliquus at concentrations of no more than 80 µg L-1. Oxidative damage partially contributed but was not the primary mechanism for the toxicity of sanguinarine on R. raciborskii. The results presented in this study indicate that sanguinarine may be a good algicidal candidate in mitigation of Raphidiopsis-based water bloom.

[Fluorescence Properties and the Detection of Benzaldehyde of Lanthanide Complex with 2-Sufoterephthalalic Acid].

A new lanthanide coordination polymer, [Eu(2-stp) (2,2'-bipy) (H2O)] · H2O (2-stp = 2-sufoterephthalalic acid, 2, 2'-bipy=2,2'-bipyridine) was obtained by hydrothermal method. The crystal structure was determined by single crystal X-ray diffraction. The complex has a one-dimensional parallel double-chain structure. Eu³âº is a nine-coordinated by six O atoms from three 2-sufoterephthalalic acids, one water molecule and two N atoms from 2,2'-bipyridine. The fluorescence properties of the complex were studied. The complex shows the characteristics narrow emission of ion at 581, 594, 619, 654 and 698 nm, corresponding to 5D0-->Fj (J = 0-4) transitions. The strongest emission peak is at 619 nm, corresponding to 5D0-F2 transition for red light. Different organic solvents have different effects on the fluorescence intensity of the complex, and enzaldehyde exerts the most significant fluorescence quenching effect. So, this complex can be used as a fluorescent sensing probe for benzaldehyde.

A novel method for linguistic steganography by English translation using attention mechanism and probability distribution theory.

To enhance our ability to model long-range semantical dependencies, we introduce a novel approach for linguistic steganography through English translation. This method leverages attention mechanisms and probability distribution theory, known as NMT-stega (Neural Machine Translation-steganography). Specifically, to optimize translation accuracy and make full use of valuable source text information, we employ an attention-based NMT model as our translation technique. To address potential issues related to the degradation of text quality due to secret information embedding, we have devised a dynamic word pick policy based on probability variance. This policy adaptively constructs an alternative set and dynamically adjusts embedding capacity at each time step, guided by variance thresholds. Additionally, we have incorporated prior knowledge into the model by introducing a hyper-parameter that balances the contributions of the source and target text when predicting the embedded words. Extensive ablation experiments and comparative analyses, conducted on a large-scale Chinese-English corpus, validate the effectiveness of the proposed method across several critical aspects, including embedding rate, text quality, anti-steganography, and semantical distance. Notably, our numerical results demonstrate that the NMT-stega method outperforms alternative approaches in anti-steganography tasks, achieving the highest scores in two steganalysis models, NFZ-WDA (with score of 53) and LS-CNN (with score of 56.4). This underscores the superiority of NMT-stega in the anti-steganography attack task. Furthermore, even when generating longer sentences, with average lengths reaching 47 words, our method maintains strong semantical relationships, as evidenced by a semantic distance of 87.916. Moreover, we evaluate the proposed method using two metrics, Bilingual Evaluation Understudy and Perplexity, and achieve impressive scores of 42.103 and 23.592, respectively, highlighting its exceptional performance in the machine translation task.

The genetic relationship between hypotension and delirium: a Mendelian randomization study.

Background: Observational research suggests that hypotension is a potential hazard factor of delirium. Nevertheless, previous observational articles are limited in their ability to establish causality between hypotension and delirium. The present study was sought to explore the genetic causal relationship between these two conditions using two-sample Mendelian randomization (MR). Methods: Genome-wide association study (GWAS) summarized data for hypotension and delirium were obtained from the FinnGen Consortium. The researchers utilized several statistical methods, such as inverse-variance weighted (IVW), weighted median, MR Egger, weighted mode, and simple mode in conducting the MR statistical analysis. In order to identify heterogeneity among the MR outcomes, we employed the Cochrane's Q test. Furthermore, we used the MR-Egger intercept test and MR pleiotropy residual sum and outliers (MR-PRESSO) test to examine horizontal pleiotropy. Results: The findings revealed that hypotension was identified as an independent hazard variable for delirium (p = 0.010, odds ratio [OR] [95% confidence interval (CI)] = 1.302 [1.066-1.592]) using the IVW method. The presence of horizontal pleiotropy was found to have minimal impact on establishing causal relationship (p = 0.999), and there was no evidence to suggest heterogeneity between genetic variations (p = 0.379). Additionally, the leave-one-out method demonstrated the stability and robustness of this association. Conclusion: We performed two-sample MR analyses and found evidence of a genetic causal relationship between hypotension and delirium. Our findings suggest that individuals with a genetic predisposition for hypotension may have a higher risk of developing delirium. This suggests that interventions aimed at improving perioperative hypotension could aid in limiting the incidence of delirium.

Photoinduced oxidation of chromium picolinate to hexavalent chromium in the presence of ferric ions.

The occurrence of chromium picolinate (Cr(pic)3) in environment has attracted raising concerns on its fate and the associated risks. Herein, the photoinduced oxidation of Cr(pic)3 in the presence of ferric ions (Fe(III)) under simulated sunlight and natural solar light irradiation were investigated. Cr(pic)3 was stable under dark or without Fe(III). 87.9 % of Cr(pic)3 (C0 = 1.0 µM) was degraded in the presence of 50 µM Fe(III) after 90 min simulated sunlight irradiation at initial pH of 4.0. •OH was the main cause for Cr(pic)3 oxidation, it attacked the chromium center to generate hexavalent chromium (Cr(VI)) and picolinic acid (k = 5.9 ×108 M-1·s-1). Picolinic acid could be further oxidized to NH4+ and small organics. Relative higher Fe(III) content (25 - 75 µM) and Cr(pic)3 concentration (0.5 - 2.0 µM) promoted both of Cr(pic)3 degradation and Cr(VI) accumulation. While, the degradation of Cr(pic)3 decreased with pH at the range of 3.0 - 8.0, more Cr(VI) was accumulated at pH 5.0 and 6.0. The co-existence of inorganic ions and dissolved organic matter (DOM) in river water inhibited Cr(pic)3 oxidation by scavenging the •OH formed and shielding the light. 8.0 - 16.7 µg/L of Cr(VI) was accumulated after 9.0 h simulated sunlight irradiation of Cr(pic)3 in river water matrix ([Fe(III)]0 = 50 - 100 µM). The generation of Cr(VI) under solar light was slower than that under simulated sunlight due to the weaker light intensity (43.2 - 85.0 mW/cm2 vs. 750 - 1300 mW/cm2). These results consistently suggest photoinduced oxidation of Cr(pic)3 in environment generates the toxic Cr(VI), which deserves significant attention.

Absolute configuration determination of SMTP-7 via microcrystal electron diffraction (MicroED).

Direct absolute configuration determination of a drug candidate bearing five chiral centers, SMTP-7, is lacking. With only few-micron-sized powders available, we assigned the absolute configuration of SMTP-7 via MicroED analysis through kinematical refinement with additional chiral information and directly through the recently developed dynamical refinement approach. We showcased the utility of the latest advance in MicroED to unambiguously assign absolute configuration for hard-to-crystallize, complex, and quantity-limited molecules.

Approaches of formulation bridging in support of orally administered drug product development.

As a drug advances through the late stages of clinical development, formulation changes are common to meet clinical, manufacturing, and/or business needs. Since some formulation changes may alter in vivo drug absorption, it is critical to understand the impact of these changes on in vivo PK performances to support the transition between pre- and post-change formulations and ensure the drug's efficacy and safety. While clinical RBA/BE studies are time-consuming and expensive, other formulation bridging approaches that bring opportunities to expedite drug development by waiving clinical formulation bridging studies are summarized. This review discussed the current formulation bridging options based on in vitro dissolution, physiologically-based biopharmaceutics modeling (PBBM), in vitro - in vivo correlation (IVIVC), and risk-based assessment during the early and late stages of clinical development. By increasing the understanding of the opportunities and challenges associated with different formulation bridging approaches, this review helps with the selection/design of formulation bridging studies in a phase appropriate manner for formulation change during product development.

A multi-objective supplier selection framework based on user-preferences.

This paper introduces an interactive framework to guide decision-makers in a multi-criteria supplier selection process. State-of-the-art multi-criteria methods for supplier selection elicit the decision-maker's preferences among the criteria by processing pre-collected data from different stakeholders. We propose a different approach where the preferences are elicited through an active learning loop. At each step, the framework optimally solves a combinatorial problem multiple times with different weights assigned to the objectives. Afterwards, a pair of solutions among those computed is selected using a particular query selection strategy, and the decision-maker expresses a preference between them. These two steps are repeated until a specific stopping criterion is satisfied. We also introduce two novel fast query selection strategies, and we compare them with a myopically optimal query selection strategy. Computational experiments on a large set of randomly generated instances are used to examine the performance of our query selection strategies, showing a better computation time and similar performance in terms of the number of queries taken to achieve convergence. Our experimental results also show the usability of the framework for real-world problems with respect to the execution time and the number of loops needed to achieve convergence.

Absolute configuration determination of pharmaceutical crystalline powders by MicroED via chiral salt formation.

Microcrystal electron diffraction (MicroED) has established its complementary role alongside X-ray diffraction in crystal structure elucidation. Unfortunately, kinematical refinement of MicroED data lacks the differentiation power to assign the absolute structure solely based on the measured intensities. Here we report a method for absolute configuration determination via MicroED by employing salt formation with chiral counterions.

Development and validation of a novel HILIC method for the quantification of low-levels of cuprizone in cuprizone-containing chow.

Cuprizone is an amide compound that has been wildly used in various animal studies, such as in the investigation of remyelination in mouse model. It is important to control the amount of cuprizone dosed in animals to be consistent as different amounts may lead to different clinical observations. Cuprizone is usually administrated as a minor component (i.e., 0.3%) of a mixture with powdered or pelleted rodent chow. Its low content, combined with the complex nature of chow, represents a significant challenge for the quantification of cuprizone in the mixture. To the best of our knowledge, no method has been reported in the literature so far. In this study, a simple, selective, and sensitive hydrophilic interaction liquid chromatographic method was developed for the quantification of cuprizone in cuprizone pre-clinical formulations. The analytical method comprises a fast ultrasound assisted extraction with acetonitrile/water as a solvent followed by gradient separation using a Waters Xbridge HILIC column with 0.1% TFA in water and acetonitrile as mobile phases and UV detection at 220 nm. The specificity, linearity, accuracy, repeatability, and limit of quantitation (LOQ) of the method were established. The method was determined to be linear in the range of 10-200 µg/mL. Accuracy was assessed by spiking a chow placebo with various amounts of a cuprizone reference standard to achieve target concentration levels and the recoveries were within the acceptance criterion of 90-110% of the target concentrations. Repeatability was demonstrated at the nominal concentration of 100 µg/mL and LOQ level of 2.5 µg/mL. This method has been demonstrated to be suitable for its intended use and has been successfully applied to the quantification of low levels of cuprizone in chow formulations. It was found that the cuprizone content in chow could varied significantly between batches and the potential causes of the variability were investigated.

Comprehensive analysis of liposome formulation parameters and their influence on encapsulation, stability and drug release in glibenclamide liposomes.

An understanding of the factors that affect liposome size, drug loading, stability and drug release is critical for the rational design of liposomes with desired pharmacokinetics and biodistribution. This article presents a report on the formulation and characterization of BIIB093 (glibenclamide) liposomes as well as a detailed analysis of the influence of formulation methods and parameters on encapsulation efficiency, liposome size, charge (zeta potential, ZP), polydispersity index (PDI), and drug release. PEGylated liposomes containing BIIB093 were made using ethanol injection and calcium acetate remote loading. The critical formulation parameters investigated include: the effect of lipid chain length, lipid unsaturation, lipid phase transition temperature (Tc) and the amount of cholesterol. Liposomes generated in this study had low average particle size (130 ± 20 nm), PDI (0.15 ± 0.1) and ZP (-2 ± 1 mV). Liposomes made from lipids with long acyl chains showed enhanced drug loading, encapsulation efficiency and drug retention. Similarly, liposomes made from lipids with high degree of unsaturation and low Tc exhibited faster drug release rates. Additionally, increasing the amount of cholesterol in the liposome bilayer improved PDI, decreased drug incorporation and accelerated drug release but had negligible impact on liposome size and ZP. Furthermore, encapsulating the drug in the liposome core enabled sustained drug release.

Prediction of in vivo performance of oral extended release formulations prior to clinical evaluation: A case study for enteric coated polymeric beads formulation.

To reduce cost and time for product development, an ideal strategy for the development of oral extended release (ER) product is to identify the desired formulation with minimum needsfor clinical evaluation. The aim of this work was to demonstrate the feasibility of adopting a "prediction-then-validation" strategy for the development of oral ER formulations. Instead of the traditional approach using multiple ER formulations for IVIVC development, an enteric-coated fast release formulation was successfully utilized for the development of a biopredictive tool to estimate the drug release from enteric coated polymeric ER formulations in the intestine. A TS1 (time scale factor between Tvitro and Tvivo equals to 1) system was designed and developed, based on which the in vivo pharmacokinetic (PK) performance of ER formulations in dog and in human were well predicted prior to in vivo evaluations. The model further passed a posteriori validation using the criteria for level A IVIVC and, as designed, provided a Tscale value of 1 for the IVIVC model.

Molecular Mechanisms of Colistin Resistance in Klebsiella pneumoniae in a Tertiary Care Teaching Hospital.

Background: Over the last two decades, the prevalence of colistin resistance among the members of Enterobacteriaceae has been increasing, particularly among Klebsiella pneumoniae isolates; this limits the potential use of colistin and leads to worsened clinical outcomes. Methods: We investigated the prevalence and genetic characteristics of colistin-resistant K. pneumoniae (COLR-KP) in clinical isolates using genomic sequencing. Results: In total, 53 K. pneumoniae isolates (4.5%, 53/1,171) were confirmed as COLR-KP, of which eight isolates carried mobile colistin-resistant (mcr) gene. Although the overall prevalence rate (0.7%, 8/1,171) of mcr-like genes in clinical K. pneumoniae remained relatively low, the presence of mcr (15.1%, 8/53) among the COLR-KP isolates indicated that the mobile resistance gene was already widespread among K. pneumoniae isolates in hospital setting. We randomly selected 13 COLR-KP isolates (four mcr-bearing and nine non-mcr-bearing isolates) for whole-genome sequencing, including two pandrug-resistant and four sequence type 11 (ST11) isolates. Phylogenetic analysis revealed that all COLR-KP isolates were genetically diverse. Among the four mcr-bearing isolates, three (KP4, KP18, and KP30) were positive for mcr-1 and one (KP23) for mcr-8; none of the other mcr genes were detected. The mcr-1 in the KP4 and KP30 isolates were located in an IncX4 plasmid (approximately 33 kb) and could be successfully transferred to Escherichia coli J53AZR. In contrast, for the mcr-8-bearing plasmid in KP23 (IncFII), colistin resistance could not be transferred by conjugation. The mcr-1-producing isolate KP18 coexists a novel plasmid-carried tigecycline resistance gene tmexCD1-toprJ1. The most common chromosomal mutation associated with colistin resistance was a T246A amino acid substitution in PmrB, which was identified in most COLR-KP isolates (11/13, 84.6%). All ST11 isolates additionally had an R256G amino acid substitution. Critical virulence factors associated with hypervirulent K. pneumoniae were detected in four COLR-KP isolates; these virulence factors included aerobactin, salmochelin, and yersiniabactin. Conclusion: We found that mcr-bearing COLR-KP emerged in our hospital and was growing at an increasing rate. Simultaneous emergence of hypervirulence and colistin-tigecycline-carbapenem resistance in the epidemic clone ST11 K. pneumoniae was also observed; this highlights the significance of active and continuous surveillance.

Molecular Analysis and Antimicrobial Resistance Pattern of Tigecycline-Non-Susceptible K. pneumoniae Isolated from a Tertiary Care Hospital of East Asia.

INTRODUCTION: Tigecycline is one of the last resorts for carbapenem-resistant K. pneumoniae (CRKP) infections. Indeed, tigecycline-non-susceptible K. pneumoniae (TNSKP) strains are increasingly treated with the use of tigecycline. In this study, we attempted to better understand their epidemiological trends and characteristics. K. pneumoniae were collected from 2017 to 2020 at the First Affiliated Hospital of Nanchang University. METHODS: Thirty-four TNSKP strains were selected during the study period, all of which were analyzed using antimicrobial susceptibility testing, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). PCR and DNA sequencing were performed for the detection of ß-lactamase genes and carbapenemase genes, and the mutation analysis of tet(A), tet(X), tet(L), tet(M), rpsJ, ramR, and oqxR, which are related to tigecycline resistance. Virulence gene and capsular genotype testing were conducted to identify whether the TNSKP strains were hypervirulent Klebsiella pneumoniae. RESULTS: An epidemiology analysis showed that Klebsiella pneumoniae carbapenemase-2 (KPC-2) was the predominant carbapenemase in tigecycline non-susceptible carbapenem-resistant K. pneumoniae (TNSCRKP) (96.7%), and the dominant clone type was ST11-K14K64 (82.4%). Among them, 55.9% (19/34) of strains were from each department of ICU, particularly EICU and neurosurgery ICU. In order to further understand the molecular mechanisms of the TNSKP, a polymerase chain reaction of the resistant determinants was carried out. The results detected many tigecycline-resistant genes, such as tet(A) (97.1%), tet(X) (17.6%), rpsJ (97.1%), and ramR (8.8%). CONCLUSION: As the results of this study reveal, we should take effective measures to control the increase in TNSKP.

A Comparative Transcriptome Between Anti-drug Sensitive and Resistant Candida auris in China.

Candida auris emerged as a pathogenic species of fungus that causes severe and invasive outbreaks worldwide. The fungus exhibits high intrinsic resistance rates to various first-line antifungals, and the underlying molecular mechanism responsible for its multidrug resistance is still unclear. In this study, a transcriptomic analysis was performed between two C. auris isolates that exhibited different anti-drug patterns by RNA-sequencing, namely, CX1 (anti-drug sensitive) and CX2 (resistant). Transcriptomic analysis results revealed 541 upregulated and 453 downregulated genes in the resistant C. auris strain compared with the susceptible strain. In addition, our findings highlight the presence of potential differentially expressed genes (DEGs), which may play a role in drug resistance, including genes involved in ergosterol and efflux pump biosynthesis such as SNQ2, CDR4, ARB1, MDR1, MRR1, and ERG genes. We also found that Hsp related genes were upregulated for expression in the anti-drug-resistant strain. Biofilm formation and growth conditions were also compared between the two isolates. Our study provides novel clues for future studies in terms of understanding multidrug resistance mechanisms of C. auris strains.