The role of diode array ultraviolet detection for the identification of synthetic cathinones

The utility of diode array ultraviolet (UV) detection for aiding in the identification of synthetic cathinones, including different sub‐classes and positional isomers is presented. For 35 synthetic cathinones, unique UV spectra are obtained for seven sub‐classes, including mostly beta ketones, where position and type of substitution on benzene rings give rise to differences in UV maxima and relative intensity of the spectral bands. This aspect is key to distinguishing positional isomers that contain differences in R substitution (mono and di) around the benzene ring, which provides complementary information to electron ionization mass spectrometry, where the latter technique cannot distinguish between these types of positional isomers. In addition, it is possible to ascertain the substitution position based on the UV spectra. For ten sets of positional isomers, it was possible to distinguish most of the positional isomers within a set. For ultra‐high performance supercritical fluid chromatography (UHPSFC) versus reversed phase ultra‐high performance liquid chromatography (UHPLC), there was at least a 10 nm blue shift in UV maximum (shift to shorter wavelengths). This highlights the importance of taking in account the effect of mobile phase on the UV maximum when performing method development in UHPSFC. Copyright © 2017 John Wiley & Sons, Ltd.     

Correlation of liquid chromatographic and biological assay for potency assessment of filgrastim and related impurities

In vivo and in vitro potency assays have always been a critical tool for confirmation of protein activity. However, due to their complexity and time consuming procedures, it remains a challenge to find an alternative analytical approach that would enable their replacement with no impact on the quality of provided information. The goal of this research was to determine if a correlation between liquid chromatography assays and in vitro biological assay could be established for filgrastim (recombinant human granulocyte-colony stimulating factor, rhG-CSF) samples containing various amounts of related impurities. For that purpose, relevant filgrastim related impurities were purified to homogeneity and characterized by liquid chromatography and mass spectrometry. A significant correlation (R² > 0.90) between the two types of assays was revealed. Potency of oxidized filgrastim was determined to be approximately 25% of filgrastim stated potency (1 × 10⁸ IU/mg of protein). Formyl-methionine filgrastim had potency of 89% of the filgrastim stated potency, while filgrastim dimer had 67% of filgrastim stated potency. A mathematical model for the estimation of biological activity of filgrastim samples from chromatography data was established and a significant correlation between experimental potency values and potency values estimated by the mathematical model was obtained (R² = 0.92). Based on these results a conclusion was made that reversed phase high performance liquid chromatography could be used as an alternative for the in vitro biological assay for potency assessment of filgrastim samples. Such an alternative model would enable substitution of a complex and time consuming biological assay with a robust and precise instrumental method in many practical cases.     

双波长半导体激光止痛效果分析

目的:采用量化指标观察分析双波长半导体激光治疗急慢性疼痛的效果.方法:使用波长为650nm/810nm的半导体激光照射患者特定组织或痛点,选择不同功率、光斑、时间进行治疗.结果:VAS评分:P<0.05、治疗总有效率为96%.结论:双波长半导体激光治疗各种急慢性疼痛疗效肯定,并可缓解因疼痛对患者睡眠、日常生活、与人交往和生活兴趣的影响,提高生活质量.     

睫状体冷冻及经巩膜二极管激光光凝治疗重症青光眼的疗效分析

目的:比较睫状体冷冻及经巩膜二极管激光光凝治疗重症青光眼的效果。方法:收集我院2006-08/2007-10重症青光眼患者72例(72眼),用睫状体冷冻及半导体二极管激光治疗,随机分为两组,睫状体冷冻组36例(36眼),于角巩膜缘后2mm区域360°用液态二氧化碳冷冻机行睫状体冷冻,共6～8点,60～120s/点。睫状体光凝组36例(36眼),于角巩膜缘后1.5mm行全周睫状体光凝,激光点数16～36点,能量1.4～2.0W,脉冲时间0.5～2s。结果:对睫状体冷冻组及睫状体光凝组进行术后观察1,7d;1,3,6mo后分析比较,术后短期内:眼压降低、术后渗出反应及疼痛等指征有显著差异(P<0.05),远期各项比较无显著差异。结论:两组方法对于治疗重症青光眼,控制眼压,缓解疼痛均有显著疗效,睫状体光凝能量确切,操作简便安全,术后眼压下降迅速,对眼睑、结膜及巩膜等影响小,眼球萎缩及光感消失等发生几率低,而睫状体冷冻对于角膜变性、角巩膜葡萄肿及先天性大眼球等激光定位困难且易穿孔者有优势。     

RP-HPLC法同时测定昆仑雪菊中绿原酸、芦丁、槲皮素和木犀草素的量

目的采用高效液相色谱-二极管阵列检测方法,建立昆仑雪菊中绿原酸、芦丁、槲皮素和木犀草素的测定方法。方法色谱柱为安捷伦HC-C18柱(250 mm×4.6 mm,5μm);流动相为甲醇-0.01%磷酸水溶液,梯度洗脱;检测波长315nm;柱温30℃;体积流量1.0 m L/min。结果昆仑雪菊中绿原酸、芦丁、槲皮素和木犀草素分别在2.0~60μg/m L(r=0.999 8)、5.0~100μg/m L(r=0.999 9)、1.0~40μg/m L(r=0.999 9)和0.5~40μg/m L(r=0.999 9)呈良好的线性关系,平均回收率分别为102.4%(RSD为1.05%)、98.6%(RSD为1.28%)、103.6%(RSD为0.95%)、101.2%(RSD为1.12%)。结论该方法操作简便、易行、稳定,具有良好的灵敏性、重现性和回收率,可用于昆仑雪菊药材的质量控制。     

Characterization of the SAR-distribution of the Sigma-60 applicator for regional hyperthermia using a Schottky diode sheet

Introduction:?Characterization of the performance of an hyperthermia applicator by phantom experiments is an essential aspect of quality assurance in hyperthermia. The objective of this study was to quantitatively characterize the energy distribution of the Sigma-60 applicator of the BSD2000 phased array system operated within the normal frequency range of 70–120?MHz. Additionally, the accuracy of the flexible Schottky diode sheet to measure E-field distributions was assessed.

Material and methods:?The flexible Schottky diode sheet (SDS) consists of 64 diodes mounted on a flexible 125?µm thick polyester foil. The diodes are connected through high resistive wires to the electronic readout system. With the SDS E-field distributions were measured with a resolution of 2.5 × 2.5?cm in a cylindrical phantom, diameter of 26?cm and filled with saline water (2?g/l). The phantom was positioned symmetrically in the Sigma-60 applicator. RF-power was applied to the 4-channel applicator with increasing steps from 25?W to a total output of 400?W.

Results:?The complete system to measure the E-field distribution worked fine and reliably within the Sigma-60 applicator. The E-field distributions measured showed that the longitudinal length of the E-field distribution is more or less constant, e.g. 21–19?cm, over the frequency range of 70–120?MHz, respectively. As expected, the radial E-field distributions show a better focusing towards the centre of the phantom for higher frequencies, e.g. from 15.3–8.7?cm diameter for 70–120?MHz, respectively. The focusing target could be moved accurately from the left to the right side of the phantom. Further it was found that the sensitivity variation of nine diodes located at the centre of the phantom was very small, e.g. <3% over the whole frequency range.

Conclusion:?The SAR distributions of the Sigma-60 applicator are in good agreement with theoretically expected values. The flexible Schottky diode sheet proves to be an excellent tool to make accurate, quantitative measurements of E-field distributions at low (25?W) and medium (400?W) power levels. An important feature of the SDS is that it enables one to significantly improve quantitative quality assurance procedures and to start quantitative comparisons of the performance of the different deep hyperthermia systems used by the various hyperthermia groups.