Objective: To establish a method for determining the molecular weight and molecular weight distribution of Poly(Lactide-co-Glycolide Acid) (PLGA) using Size Exclusion Chromatography-Refractive Index-Multiangle Laser Light Scattering (SEC-RI-MALLS) and Size Exclusion Chromatography-Refractive Index (SEC-RID), and to compare the results obtained from these two methods.
Methods: For SEC-RI-MALLS, tetrahydrofuran was used as the mobile phase, Shodex GPC KF-803L was employed as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, and an injection volume of 100 μL. For SEC-RID, tetrahydrofuran was also used as the mobile phase, Agilent PLgel 5 μm MIXD-D was used as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, differential detector temperature at 35 ℃, and an injection volume of 20 μL. The molecular weight and molecular weight distribution were calculated using Agilent’s GPC software. The newly established methods were validated methodologically, and the molecular weight and molecular weight distribution of 13 batches of samples were determined.
Results: The precision, accuracy, stability, and repeatability tests for SEC-RI-MALLS showed RSD values of 1.35%, 1.58%, 1.53%, and 1.26%, respectively. The SEC-RID method exhibited good linearity (r=0.999 9), with RSD values for precision, accuracy, stability, and repeatability tests (n=6) of 2.05%, 1.62%, 1.30%, and 2.97%, respectively. The results obtained from SEC-RI-MALLS were lower than those from SEC-RID, and the molecular weight distribution coefficient was smaller, but the results from the paired T-test performed with the value measured by SEC-RID method and the value measured by SEC-RI-MALLS method multiplied a conversion coefficient of 1.5 showed no significant difference between the two methods.
Conclusion: Both methods are stable and reliable, and can be used for the determination of PLGA molecular weight and molecular weight distribution based on the specific situations.

Ischemic stroke (IS) is a globally life-threatening disease. Presently, few therapeutic medicines are available for treating IS, and rt-PA is the only drug approved by the US Food and Drug Administration (FDA) in the US. In fact, many agents showing excellent neuroprotection but no blood flow-improving activity in animals have not achieved ideal clinical efficacy, while thrombolytic drugs only improving blood flow without neuroprotection have limited their wider application. To address these challenges and meet the huge unmet clinical need, we have designed and identified a novel compound AAPB with dual effects of neuroprotection and cerebral blood flow improvement. AAPB significantly reduced cerebral infarction and neural function deficit in tMCAO rats, pMCAO rats, and IS rhesus monkeys, as well as displayed exceptional safety profiles and excellent pharmacokinetic properties in rats and dogs. AAPB has now entered phase I of clinical trials fighting IS in China.

In-depth study of the components of polymyxins is the key to controlling the quality of this class of antibiotics. Similarities and variations of components present significant analytical challenges. A two-dimensional (2D) liquid chromatography-mass spectrometr (LC-MS) method was established for screening and comprehensive profiling of compositions of the antibiotic colistimethate sodium (CMS). A high concentration of phosphate buffer mobile phase was used in the first-dimensional LC system to get the components well separated. For efficient and high-accuracy screening of CMS, a targeted method based on a self-constructed high resolution (HR) mass spectrum database of CMS components was established. The database was built based on the commercial MassHunter Personal Compound Database and Library (PCDL) software and its accuracy of the compound matching result was verified with six known components before being applied to genuine sample screening. On this basis, the unknown peaks in the CMS chromatograms were deduced and assigned. The molecular formula, group composition, and origins of a total of 99 compounds, of which the combined area percentage accounted for more than 95% of CMS components, were deduced by this 2D-LC-MS method combined with the MassHunter PCDL. This profiling method was highly efficient and could distinguish hundreds of components within 3 h, providing reliable results for quality control of this kind of complex drugs.

In recent years,the international drug control situation has become increasingly serious.According to the statistical data of the year 2021 from UNODC,in the past decade,the trafficking volume of traditional drug(such as methamphetamine,cannabis and cocaine)has continued to rise,new psychoactive substances(NPS)have emerged one after another,the drugs as well as their precursors and metabolites have become a new group of pollutants.They widely exist in environmental media such as water,air,sludge and soil,due to the manufacture and abuse of drugs,which endangers human and animal safety.Drug detection data from environmental samples can reflect the local drug use situation objectively,real-time,accurately and effectively,which is helpful to grasp the spatial distribution and time changes,monitor the development trends of drug abuse,assess the trend of drug abuse reasonably,and assist in combating related illegal and criminal activities through comprehensive data analysis.At present,sewage monitoring has become an important means of drug monitoring in countries around the world.Sewage testing can assess drug consumption in a place reasonably,and sewage network traceability technology can reduce the scope of regional investigation of drug manufacturing dens effectively,so as to combat accurately.Drug detection in the atmosphere,sludge and soil has been carried out in some foreign countries,but it has not been used as a long-term monitoring means.Long-term monitoring of drugs from the environment in a variety of ways not only helps to effectively update the drug situation in the region,but also to better understand local trends in drug use and identify new drugs of abuse.It will provide data support for more accurate monitoring and combating drug crimes in the future.This paper reviews the methods for detecting drugs and other related compounds in different environmental matrices including sewage,atmosphere and sludge in China and other countries,including the study on the sources and forms of related compounds in different environments,the preparation of different matrix samples and the quantitative analysis of drugs from environment,as well as the existing problems and shortcomings of various detection methods.Finally,the drug detection technology and comprehensive monitoring system in the environment are prospected.

The in vitro release is an important index to evaluate the quality of liposome formulation.Currently, there is no evaluation method for the in vitro release of liposome in pharmacopoeia of various countries, which leads to the lack of unified standard and safety guarantee for the quality evaluation of liposome formulation.Taking the self-made paclitaxel derivative liposomes as an example, the paddle membrane binding method established by optimizing external release conditions was used to simulate the complete release of paclitaxel derivative drugs in 12 hours under physiological conditions.The results showed that using 0.5% SDS-HEPES as the release medium and a dialysis bag with a molecular weight cutoff of 1 000 kD to release the liposome solution met the requirements and had discrimination ability, providing a reference for the development of drug-loaded liposomes release methods in vitro.

The UPLC fingerprint of colistimethate sodium was established for the study of quality consistency.The chromatographic column was Acquity UPLC? Peptide CSH C18 (2.1 mm × 150 mm, 1.7 μm).The mobile phase A was phosphate buffer-acetonitrile (19∶1), and the mobile phase B was phosphate buffer-acetonitrile (1∶1).The mobile phase was in gradient elution at a flow rate of 0.3 mL/min.The column temperature was set at 30 °C and the detection wavelength was 210 nm.The similarity of the fingerprints was analyzed with the Similarity Evaluation System for Chromatographic Fingerprint of Tradition Chinese Medicine (Version 2012) in combination with content determination of multiple index components to evaluate the quality consistency of imported and domestic bulk drugs.The result showed that both the original and generic bulk drugs met the specified limit requirements in the European Pharmacopoeia standards, and that their UPLC fingerprints were highly similar, indicating that the quality of the two substances was consistent.Establishing a fingerprint for similarity evaluation and combining it with the results of indicator component content determination as a comprehensive evaluation method for the study of drug quality consistency of complex components has the characteristics of fast, accurate, and comprehensive, which is helpful for drug quality evaluation and provides ideas for the evaluation of antibiotic quality consistency of complex components.

Cinnabaris(α-HgS) is a mineral traditional Chinese material medica, as a tranquilizer and sedative, which is widely used in combination with herbs for the treatment of children high fever and convulsion.However, a large amount of mercury in Cinnabaris poses a potential risk to the immature central nervous system of children and probably causes severe memory disorders.Inthisstudy,three groups of juvenile rats were given low, medium, and high doses of Cinnabaris by oral gavage once a day for 14 continuous weeks, respectively.The blood mercury concentrations of the rats at different growth phases were monitored by atomic fluorescence spectrometry.The brain structural and functional changes related to the memory functions were investigated through HE staining and Morris water-maze test. Correlation analysis was conducted to clarify the dose- mercury exposure-toxic effect relationship of Cinnabaris and memory disorders.It was found thatthe blood mercury levels increased in both time- and dose-dependent manner.After the 14-week continuous administration of Cinnabaris, the pathological lesions in hippocampal neurons of rats in the high dose group were observed including pyknosis and disordered cell arrangement.In the Morris water-maze test, compared with the control group, rats in the high dose group exhibited the significantly prolonged latency to find the platform and the target quadrant, and the time spent in the target quadrant was obviously shortened. Thus, the significant correlations were established between Cinnabaris dose and mercury exposure,mercury exposure and memory disorders, respectively. In conclusion, the long-term and overdose administration of Cinnabaris in juvenile rats can increase the in-vivo mercury level, destroy the normal hippocampal morphological structure, and lead to memory disorders. This study provided scientific references for the potential mercury poisoning risks pharmacovigilance of Cinnabaris-containing paediatric formulations.

To identify the related substances of tacrolimus by LC-MS techniques, the separation of the related substances contained in tacrolimus and its stressed samples was carried out on a Agilent Eclipse Plus-C18 (150 mm × 4.6 mm,3.5 μm) column with 0.01% fomic acid solution and a mixture of acetonitrile- methyl tert-butyl ether as the mobile phase.in linear gradient elution. Electrospray positive ionization high resolution Q-TOF/MS was used for the determination of the accurate mass and elemental composition of the parent ions of all the components, thence, the structures of all the detected substances were successfully characterized through spectra elucidation and fragmentation pathways analysis. Tacrolimus and its 35 detected related substances were well separated under the established conditions, among which 2 were its isomers , 3 were listed in United States Pharmacopeia(USP), and the rest 30 were identified as unknown products having not been reported before. These results were useful for its fermentation processes and quality control.

Cbf-14 is a novel antimicrobial peptide composed of 14 amino acids.An optimized reversed phase high-performance liquid chromatographic method with electrospray-ionization quadrupole time-of-flight mass spectrometer (LC-ESI-QTOF/MS) method was developed for separation, identification and characterization of structurally related peptide impurities in Cbf-14 gel.Chromatographic separation was carried out on an Agilent ZORBAX SB-Phenyl column (150 mm × 4.6 mm, 3.5 μm), with acetonitrile-20 mmol/L ammonium formate buffer (adjusted to pH 3.0 with formic acid) as eluent using gradient elution.Under the established conditions, Cbf-14 and its structurally related peptide impurities were well separated; and a total of 24 impurities were detected and identified, of which 5 were impurities in the preparation manufacturing process and 19 were stressed products.Based on high resolution mass spectrometry analysis, the origins and formation mechanisms of these impurities were located.The obtained results are useful for the establishment of the manufacturing process, storage condition and quality control of Cbf-14 gel.

Zebrafish is a novel model organism for drug metabolism research because of its small size, easy feeding, low reproduction cost and high reproduction rate.This paper outlines the construction of zebrafish metabolic model, illustrating the advantages of zebrafish model with high genetic similarity to human, well-developed enzyme system, and low substrate effect; and then reviews the application of zebrafish model in the synthesis of various new psychoactive substances such as cannabinoids, fentanyl, piperazines, and synthetic cathinones.The common metabolic reactions in zebrafish, including phase I (oxidation, N-demethylation, O-deethylation, hydroxylation and N-desalkylation) and phase II (sulfation and glucuronidation) reactions, are summarized, and the differences between the metabolites of zebrafish and those of real human body fluid samples are mainly related to the types of enzymes.This paper also points out the great potential and further research trends of zebrafish model in the study of new psychoactive substances.