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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.

Niya Hu,1,* Dongjiang Wang,2,* Yiqing Lin,1 Jun Zou,3 Yanling Liu,1 Zhigang Xiong,3 Jian Guo,2 Lingbing Zeng,1 Junming Li1 1Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, People’s Republic of China; 2Department of Laboratory Medicine, Shanghai East Hospital, Tongji University, School of Medicine, Shanghai, People’s Republic of China; 3Department of Orthopedics, Jiangxi Provincial Children’s Hospital, Nanchang, People’s Republic of China*These authors contributed equally to this workCorrespondence: Lingbing Zeng; Junming Li Email lingbing_zeng@163.com; lisir361@163.comIntroduction: 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 β-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.Keywords: carbapenem-resistant, tigecycline-non-susceptible, Klebsiella pneumoniae

Enteric coated active pharmaceutical ingredient (API) particles can provide advantages in clinical and pre-clinical formulation development targeting intestinal drug release over traditional tablet and capsule formulations. The challenge with this approach is developing a robust coating process to achieve sufficient gastric protection and efficient intestinal release on micron sized particles. A Wurster coating fluid bed process to directly produce enteric coated API particles was developed at a 650 g scale and was scaled up to 20 kg. Generating API with low 3-dimensional aspect ratio structure was critical for this process and was achieved through a wet milling process. The starting particle size had D50 ~ 90 μm, and the D50 of the resulting coated particles could be as small as 180 μm. Scanning electron microscopy imaging and dissolution testing were used to characterize the properties of the enteric layer on the API particles as a function of coating thickness. Coated API particles achieved up to 8 h enteric protection in the gastric environment and rapid release in the intestinal environment.

A novel composite of carbon disulfide-modified magnetic ion-imprinted chitosan-Fe(III), i.e., MMIC-Fe(III) composite, was prepared as an efficient adsorbent for the simultaneous removal of tetracycline (TC) and Cd(II). This adsorbent showed excellent performance in removing TC and Cd(II) due to its rapid kinetics, high adsorption capacity, good reusability, and was well suited for use with real water samples. Kinetics studies demonstrated that the adsorption proceeded according to a pseudo-second order model. The adsorption isotherms were well described by the Langmuir model, with maximum adsorption capacity for TC and Cd(II) being 516.29 and 194.31 mg/g, respectively. The synergistic effect of TC and Cd(II) adsorption might be due to the formation of TC-Cd(II) complex bridging the adsorbate and adsorbent. These properties demonstrate the potential application of MMIC-Fe(III) for the simultaneous removal of TC and Cd(II), and may provide some information for the synergistic removal of antibiotics and heavy metals from aquatic environments.

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.

The aim of this study is to develop an at-line near infrared (NIR) method for the rapid and simultaneous determination of four structurally similar active pharmaceutical ingredients (APIs) in powder blends intended for the manufacturing of tablets. Two of the four APIs in the formula are present in relatively small amounts, one at 0.95% and the other at 0.57%. Such small amounts in addition to the similarity in structures add significant complexity to the blend uniformity analysis. The NIR method is developed using spectra from six laboratory-created calibration samples augmented by a small set of spectra from a large-scale blending sample. Applying the quality by design (QbD) principles, the calibration design included concentration variations of the four APIs and a main excipient, microcrystalline cellulose. A bench-top FT-NIR instrument was used to acquire the spectra. The obtained NIR spectra were analyzed by applying principal component analysis (PCA) before calibration model development. Score patterns from the PCA were analyzed to reveal relationship between latent variables and concentration variations of the APIs. In calibration model development, both PLS-1 and PLS-2 models were created and evaluated for their effectiveness in predicting API concentrations in the blending samples. The final NIR method shows satisfactory specificity and accuracy.

Currently numerous drugs have been observed with lower colonic absorption than small intestine absorption, which can significantly impact in vivo performance of their oral extended release (ER) products.We reviewed over 300 publications, patents, book chapters, and commercial reports of drug products from regulatory agencies for low colonic absorption (LCA) drugs and critical findings are discussed. The focuses of this article are (1) current findings on the causes of low colonic absorption to support early assessment of LCA candidates, and (2) current knowledge on successful ER strategies and technical platforms used for LCA drugs in commercial drug products to facilitate oral ER product development.Colonic drug absorption is one of the critical considerations in successful development of oral ER products. The root causes of low colonic absorption in many LCA drugs are still unclear. It is recommended to evaluate colonic drug absorption of drug candidate at early stage of oral ER product development. After evaluation, the selection of a formulation platform to develop an oral ER product needs to be carefully considered for LCA drugs. Based on the current commercial oral ER formulation platforms for LCA drugs, compounds are first divided into five types (I-V) and different ER formulation approaches with higher success rate are recommended for each type.

Bulged sites in DNA and RNA have become targets for rational drug design due to their suspected involvement in a number of key biomolecular processes. A lead compound, derived from the enediyne natural product NCS-chrom has been used to inform chemical synthesis of a family of designed probes of DNA bulges, one of which shows 80 nM affinity for a two base bulged target. Key contributors to binding of these spirocyclic compounds have been studied in order to correlate affinity and specificity with structural features. Herein, we demonstrate that the glycosyl linkage stereochemistry of the pendant aminofucosyl group plays a pivotal role in binding, and coupled with insight obtained with various bulged targets, will allow rational design of second generation ligands.

In this study, six Chinese strains of Mycoplasma mycoides subsp. mycoides small colony type (MmmSC) isolated between 1953-1960 were analysed and their molecular characteristics compared to those of the African PG1 and Afade strains, the European C305 and 138/5 strains and the closely related caprine M. mycoides subsp.mycoides large colony type Y-goat strain. PCR amplification of long DNA fragments showed that the six Chinese strains, the PG1 strain and the Y-goat strain, just like Afade, did not have the 8.84 kb deletion characteristic of the European strains C305 and 138/5. In comparison, the lppB gene sequence of the six MmmSC Chinese strains was found to be 99% homologous to that of PG1and Afade, but93% homologous to the Y-goat sequence. The anti-rLppB antiserum reacted with PG1, Y-goat and the six Chinese strains at 67 kDa sites in Western blot, indicating that the lppB gene and its encoding protein exist in the Chinese strains. Multilocus sequence analysis (MLSA) of MmmSC strains from various regions confirmed that the Chinese strains were identical to the African and Australian cluster. This finding was further supported by the outcome of selective primer amplification. Based on these results, it is suggested that CBPP in China may have originated from Australia.

Of the commonly recognized structural elements within nucleic acids, bulges are among the least developed as targets for small molecules. Bulges in DNA and RNA have been linked to biomolecular processes involved in numerous diseases, thus probes with affinity for these targets would be of considerable utility to chemical biologists and medicinal chemists. Despite such opportunity, there is a dearth of small molecules available with affinity for bulges, which has hampered exploitation of these key targets. We have used guided chemical synthesis to prepare small molecules capable of binding to DNA and RNA bulges. Our design is based on a template which mimics a metabolite of the enediyne neocarzinostatin. The key spirocylic building block was formed through an intramolecular aldol process and the parent template shows pronounced affinity for 2 base bulges. Functionalization with specific aminosugar moieties confers nanomolar binding affinity for selected bulged DNA targets, and installation of reactive functional groups allows covalent modification of bulges. These rationally designed agents can now be used to study the stereochemistry and architecture of bulge-drug complexes and investigate the molecular biology of bulge induced processes. Members of this class have been shown to induce slipped synthesis of DNA, suggesting the agents, in addition to recognizing and binding to pre-formed bulges, can also induce bulge formation on demand.

Chimeric enediynes composed of a photoactivatable warhead coupled either to a porphyrin or spiroalcohol have been prepared. The molecules underwent photoactivation to produce diaryl radicals paving the way for applications in targeted photodynamic therapy.

Of the commonly recognized structural elements within nucleic acids, bulges are among the least developed as targets for small molecules. Bulges in DNA and RNA have been linked to biomolecular processes involved in numerous diseases, thus probes with affinity for these targets would be of considerable utility to chemical biologists and medicinal chemists. Despite such opportunity, there is a dearth of small molecules available with affinity for bulges, which has hampered exploitation of these key targets. We have used guided chemical synthesis to prepare small molecules capable of binding to DNA and RNA bulges. Our design is based on a template which mimics a metabolite of the enediyne neocarzinostatin. The key spirocylic building block was formed through an intramolecular aldol process and the parent template shows pronounced affinity for 2 base bulges. Functionalization with specific aminosugar moieties confers nanomolar binding affinity for selected bulged DNA targets, and installation of reactive functional groups allows covalent modification of bulges. These rationally designed agents can now be used to study the stereochemistry and architecture of bulge-drug complexes and investigate the molecular biology of bulge induced processes. Members of this class have been shown to induce slipped synthesis of DNA, suggesting the agents, in addition to recognizing and binding to pre-formed bulges, can also induce bulge formation on demand.

Based on fluorescence binding studies and 1D 1H NMR studies, designed synthetic analogues of NCSi-gb bind specifically with two-base bulged RNA, including HIV-2 TAR RNA, making them potential lead compounds for antiviral drug development.