左氧氟沙星与奥硝唑氯化钠注射液配伍稳定性考察

目的:考察左氧氟沙星与奥硝唑氯化钠注射液配伍稳定性.方法:在室温(20℃)条件下采用紫外分光光度法考察左氧氟沙星与奥硝唑配伍后在6 h内含量变化,并观察配伍液的外观及pH值变化.结果:左氧氟沙星与奥硝唑氯化钠注射液配伍后外观、pH值及含量均无明显变化.结论:左氧氟沙星与奥硝唑氯化钠注射液在6 h内可以配伍使用.     

人工泪液氯霉素滴眼液的含量测定和稳定性考察

目的:制定人工泪液氯霉素滴眼液含量测定方法并预测室温存放的有效期.方法:以双波长紫外分光光度法测定氯霉素含量,银量法测定含氯量,采用Q10法预测人工泪液氯霉素滴眼液的有效期.结果:氯霉素浓度在5～40μg·ml-1的范围内与吸收度差值呈良好的线性关系,氯霉素平均回收率为100.77%,RSD为0.37%.人工泪液氯霉素滴眼液在室温25℃下的有效期(t0.9)为9.3个月.结论:含量测定及贮存期预测方法简便、快速、准确可靠,适用于医院制剂的质量控制.     

Bioreversible quaternary N-acyloxymethyl derivatives of the tertiary amines bupivacaine and lidocaine—synthesis, aqueous solubility and stability in buffer, human plasma and simulated intestinal fluid

Design of water-soluble prodrugs may constitute a means to improve the oral bioavailability of drugs suffering from dissolution rate-limited absorption. The model drug bupivacaine containing a tertiary amine function has been converted into bioreversible quaternary N-acyloxymethyl derivatives. The pH-independent solubility of the N-butanoyloxymethyl derivate exceeded 1000 mg ml⁻¹ corresponding approximately to a 10,000-fold increase in water solubility compared to that of bupivacaine base. The kinetics of hydrolysis of the prodrugs was studied in the pH range 0.1–9.8 (37 °C). Decomposition was found to follow first-order kinetics and U-shaped pH-rate profiles were constructed. The observed differences between the hydrolytic lability of the derivatives might most likely be ascribed to steric effects. In most cases, the prodrugs were quantitatively converted into bupivacaine. However, for the hydrolysis of the N-butanoyloxymethyl derivative at neutral to slightly alkaline pH parallel formation of bupivacaine (80%) and an unknown compound X (20%) was observed. LC–MS analysis of the latter compound suggests that an aromatic imide structure has been formed from an intramolecular acyl transfer reaction involving a nucleophilic attack of the amide nitrogen atom on the ester carbonyl carbon atom. Whereas the derivatives were poor substrates for plasma enzymes; they were hydrolyzed rapidly to parent bupivacaine in the presence of pancreatic enzymes (simulated intestinal fluid) at 37 °C. The data indicate that such prodrugs possess sufficient stability in the acidic environment of the stomach to reach the small intestine in intact form where they can be cleaved efficiently by action of pancreatic enzymes prior to drug absorption. Thus, the N-acyloxymethyl approach might be of potential utility to enhance oral bioavailability of tertiary amines exhibiting pK_a values below approximately 6 and intrinsic solubilities in the low μM range.     

米团花色素的提取及其稳定性研究

米团花色素是云南省某些地区居民使用的一种传统黄色天然食用色素.本研究表明,米团花色素在433 nm和326 nm处分别有一个较强吸收峰.稳定性实验表明:该色素对酸、热、光、氧化剂过氧化氢(不加热)、常见金属离子、食盐及食糖等稳定,但在碱性条件或亚硫酸钠存在时不太稳定.此外,加入过氧化氢后加热也会引起其吸光值的显著改变.初步确定米团花色素主要为胺类物质.在正常加工条件下,是一种较理想的天然食用色素.     

急性脑梗死患者颈动脉硬化斑块稳定性的影响因素

【摘要】 目的 分析急性脑梗死患者颈动脉硬化斑块情况,并探讨影响其斑块稳定性的相关危险因素。方法 选取2012年5月~2017年5月我院收治的128例急性脑梗死患者作为研究对象,采用回顾性分析法分析所有患者的临床资料,根据资料可知所有患者均行颈动脉彩超及相关临床指标的检测以及一般临床资料的记录,分析检查和检测结果记录所有患者颈动脉硬化斑块形成以及其稳定情况和相关临床指标水平,并比较颈动脉硬化斑块不同稳定状况急性脑梗死患者上述资料的差异性,研究其与斑块稳定的相关性。结果 经颈动脉彩超检查结果可知,128例急性脑梗死患者均形成颈动脉硬化斑块,其中斑块稳定70例（5469%）,斑块不稳定58例（4531%）。两组患者在TC、TG、FPG和UA水平的比较上均无差异（P＞005）,但斑块不稳定的急性脑梗死患者Hcy、CyC、CRP、FIB、LDL以及IL 6和ICAM １水平均显著高于斑块稳定的急性脑梗死患者（P＜005）。非条件单因素Lgistic回归模型分析显示,急性脑梗死颈动脉硬化斑块不稳定患者中Hcy、CyC、CRP、FIB、LDL以及IL 6和ICAM １水平升高比例均显著高于斑块稳定患者（P＜005）。经非条件多因素Logistic回归模型分析得Hcy、CyC、CRP以及FIB水平升高均为导致急性脑梗死患者颈动脉硬化斑块不稳定的独立危险因素（P＜005）。结论 绝大部分急性脑梗死患者均存在颈动脉硬化斑块,且这些患者中有将近一半其斑块处于不稳定状态,而患者机体Hcy、CyC、CRP以及FIB表达水平过高均为导致急性脑梗死患者颈动脉硬化斑块不稳定的独立危险因素。     

Non-Viral Peptide-Based Approaches to Gene Delivery

Abstract

To achieve effective non-viral gene therapy, the control of in vitro and in vivo stability, cellular access, intracellular trafficking and nuclear retention of plasmids must be achieved. Inefficient endosomal release, stability against cytosolic nucleases, cytoplasmic transport and nuclear entry of plasmids are amongst some of the key limiting factors in the use of plasmids for effective gene therapy. Synthetic peptide-based gene delivery systems can be designed for DNA compaction, serum stability, cell-specific targeting, endosomo-lysis, cytoplasmic stability and nuclear transport. The stability of compacted DNA under physiological conditions can be enhanced by the use of hydrophilic polymers, such as polyethylene glycol. The aims of this review are to (i) explore theoretical and experimental aspects of DNA compaction, (ii) describe approaches for stabilizing compacted DNA, (iii) assess techniques used for characterization of compacted DNA, and (iv) review possible use of peptides for efficient gene transfer.     

Reconstituted mRNA COVID-19 vaccines may maintain stability after continuous movement

ObjectivesThere is an urgent need to ameliorate the possibilities of transporting reconstituted mRNA vaccines from the centralized preparation centres to the vaccination sites to improve the efficiency of the vaccination campaign against coronavirus disease 2019 (COVID-19). We have analysed the integrity of the Pfizer–BioNTech and Moderna vaccines under different movement conditions to provide information that may improve the distribution of vaccines to the target population.MethodsSyringes of reconstituted Pfizer–BioNTech or Moderna COVID-19 vaccines were prepared in a laminar flow chamber to be subjected to a stability analysis in order to evaluate the impact of movement on mRNA integrity. RNA integrity was checked by the lack of RNA peaks under the original mRNA peak in the electropherogram resulting from potential fragments from RNA degradation. Samples were then exposed for 180 min at room temperature (21 ± 1°C, 55 ± 10% humidity) under different movement conditions.ResultsWe report that the integrity of the mRNA in the reconstituted COVID-19 vaccines after continuous moderate movement at room temperature is maintained for at least 3 hours, with values of fluorescence units (FU) under the original mRNA peak of 0.38 ± 0.06 in the Pfizer–BioNTech vaccine and 0.96 ± 1.18 FU in the Moderna vaccine, equal to the values obtained without movement (0.36 ± 0.08 FU in the Pfizer–BioNTech and 1.12 ± 0.19 FU in the Moderna). In contrast, the integrity of these vaccines exposed to repeated Vortex shaking was significantly impaired (p < 0.001) with values under the original mRNA peak of 1.34 ± 0.31 FU for the Pfizer–BioNTech and 5.03 ± 1.16 FU for the Moderna samples.ConclusionsThe stability of these reconstituted vaccines reported here may improve the efficiency of the ground transportation and distribution of the vaccines, which may lead to shorter and more homogeneous vaccinations in cities and rural areas.     

Development of a lyophilized soybean paste certified reference material for the analysis of ochratoxin A

A certified reference material (CRM) [²KRISS CRM # 108-10-018] for the analysis of ochratoxin A (OTA) in doenjang (fermented soybean paste and popular food in Korea) was produced to ensure the reliability of analytical results in testing laboratories. A home-made doenjang was chosen as a raw material after testing its OTA level. The raw material was freeze-dried, pulverized, sieved and homogenized. An isotope-dilution-liquid chromatography/tandem mass spectrometric method (ID-LC/MS/MS) which was previously developed and validated in this laboratory was used as a higher-order reference method for characterization, homogeneity studies, and short-term stability studies. The CRM had good between-bottle homogeneity with 0.56% relative standard deviation among 10 selected units. The stability of the CRM at −70 °C (the storage condition in our laboratory) and at −20 °C (the possible storage temperature at user sites) were tested for up to 8 months. No change in the OTA content was observed within the measurement uncertainty. The stability of the CRM at room temperature (for regular use and transportation) was also tested and confirmed. The certified value was (49.50 ± 1.17) μg/kg, where the expanded uncertainty was in the confidence level of 95%.     

Estimating fall risk with inertial sensors using gait stability measures that do not require step detection

Falls have major consequences both at societal (health-care and economy) and individual (physical and psychological) levels. Questionnaires to assess fall risk are commonly used in the clinic, but their predictive value is limited. Objective methods, suitable for clinical application, are hence needed to obtain a quantitative assessment of individual fall risk. Falls in older adults often occur during walking and trunk position is known to play a critical role in balance control. Therefore, analysis of trunk kinematics during gait could present a viable approach to the development of such methods. In this study, nonlinear measures such as harmonic ratio (HR), index of harmonicity (IH), multiscale entropy (MSE) and recurrence quantification analysis (RQA) of trunk accelerations were calculated. These measures are not dependent on step detection, a potentially critical source of error. The aim of the present study was to investigate the association between the aforementioned measures and fall history in a large sample of subjects (42 fallers and 89 non-fallers) aged 50 or older. Univariate associations with fall history were found for MSE and RQA parameters in the AP direction; the best classification results were obtained for MSE with scale factor τ = 2 and for maximum length of diagonals in RQA (72.5% and 71% correct classifications, respectively). MSE and RQA were found to be positively associated with fall history and could hence represent useful tools in the identification of subjects for fall prevention programs.