Quantification of six bioactive compounds in Zhenqi Fuzheng preparation by high-performance liquid chromatography coupled with diode array detector and evaporative light scattering detector

A simple and accurate high-performance liquid chromatography（HPLC）coupled with diode array detector（DAD）and evaporative light scattering detector（ELSD）was established for the determination of six bioactive compounds in Zhenqi Fuzheng preparation（ZFP）.The monitoring wavelengths were 254,275 and 328 nm.Under the optimum conditions,good separation was achieved,and the assay was fully validated in respect of precision,repeatability and accuracy.The proposed method was successfully applied to quantify the six ingredients in 31 batches of ZFP samples and evaluate the variation by hierarchical cluster analysis（HCA）,which demonstrated significant variations on the content of these compounds in the samples from different manufacturers with different preparation procedures.The developed HPLC method can be used as a valid analytical method to evaluate the intrinsic quality of this preparation.

A High Performance Terahertz Waveguide Detector Based on a Low-Barrier Diode

A Schottky barrier diode with low-barrier is presented, based on which a terahertz waveguide detector working at 500-600 GHz is designed and fabricated. By using the InGaAs/InP material system, the feature of the low barrier is obtained which greatly improves the performance of the detector. The measured typical voltage responsivity is about 900 V/W at 50-560 OHz and is about 400 V/W at 560 600 GHz. The proposed broadband waveguide detector has the characteristics of simple structure, compact size, low cost and high performance, and can be used in a variety of applications such as imaging, moleeuIar spectroscopy and atmospheric remote sensing.

Dosimetric evaluation using the diode measurements for total skin electron therapy technique

Objective： The purpose of this study was to present the dosimetric study and evaluation the dose delivered to the skin tumor by using diode detector with total skin electron therapy （TSET）. Methods： The total skin electron irradiation （TSEI） technique was used to treat ten patients with histological confirmed mycosis fungoides according to the Stanford staging system at the Radiotherapy Department, National Cancer Institute, Cairo University, Egypt. High dose rate electron beams with low electron energy 5 MeV from a Siemens linear accelerator were used for treatment. Diodes were calibrated at TSET distance 300 cm and field size （35 × 35） cm^2. Results： The result of diodes measurements showed the dose to flat surface of the body was within ：1：10 % from the prescribed dose. Special areas of the body such as the perineum ＆ eyelid showed large deviation up to 30% variation from the prescription dose. Conclusion： The diode results of this study will be used as a quality assurance check for all new patients treated with TSET and to compare it to the prescribed dose delivered to the patients. It is recommends to evaluate the diodes measurements for all patients throughout the full treatment cycle and to identify individually the boost dose areas.

Validation of Metformin Hydrochloride in Human Plasma by HPLC-Photo Diode Array （PDA） for Application of Bioequivalence Study

A sensitive and specific high performance liquid chromatography （HPLC） method was developed and validated for the simultaneous determination of metformin hydrochloride （HCI） in human plasma. The HPLC method consists of isocratic eluation with a mixture of 60% buffer （10 mM sodium dihyrogenphosphate-10 mM sodium dodecyl sulphate） and 40% acetonitrile with final pH 7.0 with flow rate of 1.0 mL/min on a Kromasil~ Akzo Nobel RP-18 （4.6 mm ID ~ 250 mm, 5 ~tm） column at an ambient temperature. Photo diode array detection was performed in program mode at 234 rim. The analyte and diazepam as internal standard （IS） were extracted from plasma using 10% trichloroacetic acid. The assay was linear over the therapeutic concentration range of 20-2,500 ng/mL for metformin HCI with correlation coefficient of r = 0.9999. Limit of quantitation was 20 ng/mL. The results obtained for intraJinter day accuracy and precision complied very well with the generally accepted criteria for bio-analytical assay. The method was applied to bioequivalence （BE） study of metformin HCI in healthy Indonesian volunteers after treatment with 750 mg XR metformin HCI. This BE study shows that the two formulations are equivalent so that they were therapeutically interchangeable for each other.

Study and ICH validation of a reverse-phase liquid chromatographic method for the quantification of the intact monoclonal antibody cetuximab

Cetuximab （CTX） is a potent chimeric mouse/human monoclonal antibody （mAb） approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses per- formed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-perfor- mance liquid chromatography with diode array detection （（RP）HPLC/DAD） is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmo- nization guidelines （ICH） for biotechnological drugs; therefore, we evaluated linearity, accuracy, preci- sion, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by compre- hensive chromatographic analysis by subjecting CTX to several informative stress conditions. As de- monstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also suc- cessfully used to quantify CTX in a long-term stability study performed under hospital conditions.

Uncertainties of ＂in v/vo＂ Dosimetry Using Semiconductors

The purpose of the present study is to evaluate the uncertainties of in vivo dosimetry measured with diode detectors for conformal radiation therapy techniques in order to define appropriate tolerance levels for pelvis and breast treatment in MEIH （Middle East Institute of Health）. The present work is carried out on 30-472 and 30-473 diode detectors irradiated by 4 and 15MV photon beams of a medical linear accelerator Synergy from ELEKTA. Dose computation is performed with Pinnacle 7.4 k treatment planning system. First, an estimation of the uncertainties in a simple geometric case, using a water-equivalent solid phantom is done. Secondly, each treatment parameter such as field size, beam angle, beam modifiers and source-skin distance is evaluated in order to simulate the conformal radiation treatments used in the present institution for the main anatomical sites. Interpretation of entrance dose in-vivo measurements requires the determination of appropriate tolerance levels. Indeed, the authors found that the 5% action level proposed in the literature underestimates the uncertainties in the treatment process. A method for the evaluation of tolerance/action levels related to the different anatomical sites is developed. By the end of the present study the authors have developed an integrated monitoring system that offers accurate information about the dose received by patients.

Simultaneous Determination of Saponins in Radix Glycyrrhizae, Notoginseng and Ginseng by High Performance Liquid Chromatography

To establish a method for determining five saponins(notoginsenoside R1, ginsenoside Rg1, ginsenoside Re, ginsenoside Rb1 and ammonium glycyrrhizinate) in Glycyrrhizae, Notoginseng and Ginseng, the high performance liquid chromatography with diode array detector(HPLC-DAD) method was applied to an Inertsil ODS-SP column(4.6 mm×250 mm, 5 μm) with a mobile phase consisting of acetonitrile-0.05% phosphoric acid in a gradient elution manner. The flow rate was 1.0 mL/min. The column temperature was 30 ℃ and the detection wavelengths were 203 nm and 237 nm, respectively. The linear ranges were 0.700,0—7.000,0 μg for R1(r=1.000,0), 0.751,1— 7.511,4 μg for Rg1(r=1.000,0), 0.677,2—6.771,6 μg for Re(r=1.000,0), 0.733,9—7.339,1 μg for Rb1(r= 1.000,0), and 0.540,0—5.399,8 μg for ammonium glycyrrhizinate(r=0.999,9), respectively. In addition, their average recoveries were 100.28%, 105.83%, 104.09%, 99.36% and 98.54%, respectively. The relative standard deviations(RSDs) of precision, reproducibility and recovery were all less than 1.5%. The results indicate that the method is simple, accurate and reproducible so that it can be used for the simultaneous determination of the five saponins in Chinese patent medicines containing the three kinds of herbs.

Study on chromatographic fingerprint of sarcandra glabra (Thunb.) by microwave-assisted extraction coupled to HPLC/DAD

Microwave-assisted extraction(MAE)was used for extraction of effective components of sarcandra glabra(Thunb.),and then chromatographic fingerprint of sarcandra glabra(Thunb.)was studied by high performance liquid chromatography/diode array detector(HPLC/DAD).The conditions of MAE were optimized by an orthogonal experiment,and then the authentication and validation of the chromatographic fingerprint were conducted.Nine peaks were identified as common peaks in the fingerprint chromatograms,and isofraxidin was considered as a reference compound and quantified.Relative standard deviations of retention time and peak area of each component were less than 3% and 8%,respectively.Similarity and difference analysis were conducted by use of PCA and relation coefficient.Twenty batches of sarcandra glabra(Thunb.)samples from two different producing areas could be classified into two different groups in the PCA model.The results showed that MAE-HPLC/DAD method was simple,efficient and stable for the study of complex chromatographic fingerprint of sarcandra glabra(Thunb.),which could provide more reliable and precise information for quality evaluation.

Developing a Novel Single-Marker-Based Method for the Quantitative Evaluation of the Multiple Active Components in Corydalis yanhusuo W. T. Wang

Objective: This study was designed to develop a method for detecting differences in the chemical composition of Corydalis yanhusuo W. T. Wang using high-performance liquid chromatography with a diode array detector technology. Materials and Methods: We established a novel quantitative evaluation method for identifying multiple components in natural extracts using a single-marker method quantitative analysis of multi-components by single marker(QAMS). This method was then validated using eight alkaloid phytochemical markers designed to evaluate C. yanhusuo quality. Results: Our evaluations revealed good linearity(R^(2) ≥ 0.9991) within the range of tested concentrations for all eight alkaloids, with recovery ranging from 95.5% to 101.5%. The evaluations also returned stability results that fell within the acceptable range. Cluster analysis and Heatmap analyses were applied to classify and evaluate alkaloids across 21 different production areas. These results revealed a significant difference in the component profiles between samples from different origins. Conclusions: Thus, these data suggest that in the absence of a material reference, QAMS may help facilitate the stable production of C. yanhusuo. In addition, our data suggest that this method may have value as a promising alternative to common quality evaluations for controlling C. yanhusuo composition.

Energy response improvement for photon dosimetry using pulse analysis

During the last few years,active personal dosimeters have been developed and have replaced passive personal dosimeters in some external monitoring systems,frequently using silicon diode detectors.Incident photons interact with the constituents of the diode detector and produce electrons.These photon-induced electrons deposit energy in the detector＇s sensitive region and contribute to the response of diode detectors.To achieve an appropriate photon dosimetry response,the detectors are usually covered by a metallic layer with an optimum thickness.The metallic cover acts as an energy compensating shield.In this paper,a software process is performed for energy compensation.Selective data sampling based on pulse height is used to determine the photon dose equivalent.This method is applied to improve the energy response in photon dosimetry.The detector design is optimized for the response function and determination of the photon dose equivalent.Photon personal dose equivalent is determined in the energy range of 0.3-6 MeV.The error values of the calculated data for this wide energy range and measured data for ^133Ba,^137Cs,^60Co and ^241Am-Be sources respectively are up to 20%and 15%.Fairly good agreement is seen between simulation and dose values obtained from our process and specifications from several photon sources.

A readout integrated circuit based on DBI-CTIA and cyclic ADC for MEMS-array-based focal plane

A readout integrated circuit （ROIC） for a MEMS （microelectromechanical system）-array-based focal plane （MAFP） intended for imaging applications is presented. The ROIC incorporates current sources for diode de- tectors, scanners, timing sequence controllers, differential buffered injection-capacitive trans-impedance amplifier （DBI-CTIA） and 10-bit cyclic ADCs, and is integrated with MAFP using 3-D integration technology. A small-signal equivalent model is built to include thermal detectors into circuit simulations. The biasing current is optimized in terms of signal-to-noise ratio and power consumption. Layout design is tailored to fulfill the requirements of 3-D integration and to adapt to the size of MAFP elements, with not all but only the 2 bottom metal layers to complete nearly all the interconnections in DBI-CTIA and ADC in a 40/zm wide column. Experimental chips are designed and fabricated in a 0.35 μm CMOS mixed signal process, and verified in a code density test of which the results indicate a （0.29/-0.31） LSB differential nonlinearity （DNL） and a （0.61/-0.45） LSB integral nonlinearity （INL）. Spectrum analysis shows that the effective number of bits （ENOB） is 9.09. The RO1C consumes 248 mW of power at most if not to cut off quiescent current paths when not needed.