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.

Objective To investigate the correlation between preoperative N-terminal pro-B-type natriuretic peptidogen(NT-proBNP)levels and early postoperative outcomes in elderly and critically ill pa-tients with hip fractures.Methods A total of 593 elderly and critically ill patients with hip fractures from January 2018 to April 2021 were selected,including 189 males and 404 females,aged≥65 years,BMI 12.0-35.5 kg/m2,ASA physical status Ⅱ-Ⅳ.General preoperative information,intraoperative and post-operative discharge outcomes of patients were retrospectively obtained by the electrical clinical medical record system or telephone follow-up.The receiver operator characteristic(ROC)curve of preoperative plas-ma NT-proBNP and postoperative 30-day death was plotted,and the corresponding optimal cut-off value was 1 765.0 pg/ml.According to NT-proBNP values,the patients were divided into two groups:low-ratio group(NT-proBNP≤1 765.0 pg/ml,group L,n = 463)and high-ratio group(NT-proBNP＞1 765.0 pg/ml,group H,n = 130).The correlation between different plasma concentrations of NT-proBNP before surgery and ICU length of stay,total length of stay,postoperative complications,and 30-day mortality rate were an-alyzed using univariate and multivariate logistic regression analysis.Results Compared with group L,age,preoperative comorbidities with coronary heart disease,arrhythmia,chronic heart failure,lung disease,and chronic kidney disease,as well as mortality within 30 days after surgery were significantly increased in group H(P＜0.05).The multivariate logistic regression analysis showed that high preoperative plasma NT-proBNP concentration was positive correlation with postoperative ICU length of stay(OR = 1.215,95%CI 1.073-1.375,P = 0.020)and 30-day mortality rate(OR = 32.696,95%CI 7.158-149.338,P＜0.001).Conclusion High preoperative plasma NT-proBNP concentration is positive correlation with postoperative ICU hospitalization timeand 30-day mortality.

At present , methamphetamine has become a major hidden danger in global public health safety. In order to judge methamphetamine addicts and methamphetamine abstainers more scientifically and reliably, this study analyzed the endogenous metabolites in plasma, serum and urine of methamphetamine addicts, methamphetamine abstainers and healthy volunteers by highly sensitive high-throughput liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) analytical instrument. The obtained metabolomic data were processed by univariate analysis (t-test) and multivariate analysis (PLS-DA and OPLS-DA) and eligible potential biomarkers were then screened.The identified biomarkers set enrichment analysis to find the connection between metabolites and metabolic pathways.Multivariate statistical results showed that methamphetamine acute group, recovery group and healthy group were clearly separated.3, 18 and 6 regulated metabolites were identified in serum, plasma and urine, respectively, suggesting that lipid metabolism was abnormal in methamphetamine acute group, and that fatty acid metabolism, sulfate/sulfite metabolism and sex hormone metabolism were abnormal in methamphetamine recovery group.The selected potential biomarkers in this study provide the possibility for scientific judgment of the clinical stage of methamphetamine detoxification.

A novel method was developed for the content assay and related substances determination of neomycin sulfate by high performance liquid chromatography combined with pulsed amperometric detection(HPLC-PAD). The HPLC was performed on Thermo AcclaimTMAmG C18(4. 6 mm×150 mm, 3 μm). The mobile phase consisted of aqueous solution with 2% trifluoroacetic acid containing 0. 01% pentafluoropropionic acid and 0. 6%NaOH. The pulsed amperometric detector was operated with aquadruple-potential waveform for the detection. Neomycin B, Neomycin C and thirteen related substances were adequately separated by the established HPLC conditions. The limits of detection(LOD)and quantification(LOQ)of neomycin B and neomycin C were both 1. 75 ng and 3. 5 ng, respectively. Good linearities of neomycin B and neomycin C were found in their respective ranges which their correlation coefficients were greater than 0. 998 5. The established method is characterized by high specificity, sensitivity and wide range of linearity which has a good application prospect and provides the basis for improving the standard and quality control of neomycin sulfate.

An LC-TOF /MS and LC-MS /MS method was established for the identification the related substances in ambrisentan.HPLC separation was carried out on an XBridge C18 column(4.6 mm ×150 mm,3.5 μm)with linear gradient elution using a mobile phase consists of acetonitrile,water and 0.15% formic acid.The structures of the related substances were identified by electrospray positive ESI high resolution TOF /MS and MS /MS spec-tra,and verified further through reference substances.Ambrisentan and its related substances can be separated under the established HPLC conditions.Ten related substances were detected and identified.The established method is useful for the identification of related substances in ambrisentan.The results obtained are valuable for its manufacturing process optimization and quality control.

An LC-MS method was established for the identification of the related substances in rivaroxaban. HPLC separation was carried out on an Inert Sustain C18 column(250 mm×4. 6 mm, 5 μm)with linear gradient elution using a mobile phase consisting of 0. 2% formic acid acetonitrile and 0. 2% formic acid aqueous solution. Rivaroxaban and its related substances could be completely separated under the established HPLC conditions. The structures of the related substances were identified by electrospray positive ESI high resolution TOF/MS and MS/MS spectra determination and elucidation, and further verified through reference substances. Fifteen related substances were detected and identified to be three related substances of starting materials, four synthetic by-products and ten degradation products. The established method is useful for the identification of the related substances in rivaroxaban. The results obtained are valuable for its manufacturing control and quality assurance.

Objective To investigate the effects of reducing APE/Refl expression in the cultures of rat spiral ganglion cells with oxidative damage induced by H2O2.Methods Primary cultured rat spiral ganglion cells were infected with small interfering RNA to APE/Refl (Apel siRNA) for 72 h,followed by treating with H2O2(0,10,25,50,100 and 300 μmol/L) for 1 h,and then cultured in normal medium for 24 h.Western blot were used to detect the level of APE/Refl protein and phosphorylation of histone protein H2AX in the infected cells.The caspase3 activation was tested by spectrophotometric method.The cell viability was determined by MTT and the apoptosis of spiral ganglion cells was determined by terminal-deoxynucleotidyl transferase mediated nick and labeling (TUNEL).Results Western blot showed that infection with Ape1siRNA resulted in APE/Ref1 reduced expression in the spiral ganglion cells.Exposing spiral ganglion cultures with reduced expression of APE/Ref1 to H2O2 (50,100,300 μmol/L) for 1 h resulted in increasing in the phosphorylation of histone protein H2AX.The reduction in APE/Refl significantly reduced cell viability in cultures 24 h after 1 h expression to 50-300 μmol/L H2O2.The apoptosis of cells and caspase 3 activity was detected significantly improved.Conclusions The induced of APE/Refl results in significantly decrease in spiral ganglion cells viability in oxidative stress.The repairing function of APE/Refl is necessary for optimal levels of neuronal rat spiral ganglion cells survival.

Inosiplex is a compound formulation composed of inosine and p-acetaminobenzoic acid (PABA) salt of N,N-dimethylamino-2-propanol (DIP). This study was to investigate the clinical plasma pharmacokinetic properties of DIP and PABA after single and multiple oral doses of inosiplex tablets in healthy Chinese volunteers. The established LC/MS/MS method for plasma DIP determination had a linear range of 0.02-10 mg/mL, and the HPLC method for plasma PABA determination had a linear range of 0.05-40 mg/mL. Linear pharmacokinetic characteristics were found with single oral doses of 0.5, 1.0 and 2.0 g. No obvious accumulation effects were observed for DIP and PABA.

After oral administration of Salvia miltiorrhiza (Danshen in Chinese), Panax notoginseng (Sanqi in Chinese) and Danshen Sanqi combination suspensions to Beagle dogs, the plasma concentration-time profiles of danshensu, tanshinone II(A), cryptotanshinone, notoginsenoside R1, ginsenoside Rg1 and Rb1 were analyzed by LC-MS/MS. Pharmacokinetic parameters were calculated and analyzed with BAPP 2.0 software. The results showed that the Cmax and AUC of danshensu, notoginsenoside R1, ginsenoside Rg1 and Rb1 in Danshen Sanqi combination group all decreased in comparison with those of Danshen or Sanqi given alone, while the CLz/F and Vz/F increased to some extent. No significant differences of the pharmacokinetics of tanshinone II(A) and cryptotanshinone were observed between groups.