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Quantification of sofosbuvir and ledipasvir in human plasma by UPLC–MS/MS method: Application to fasting and fed bioequivalence studies
No full textA rapid and sensitive LC–MS/MS method was developed, optimized and validated for quantification of sofosbuvir (SF) and ledipasvir (LD) in human plasma using eplerenone as an internal standard (IS). Analytes and IS were extracted from plasma by simple liquid–liquid extraction technique using methyl tertiary butyl ether. The prepared samples were chromatographed on Acquity UPLC BEH C18 column. Separation was done using a mobile phase formed of 0.1% formic acid and acetonitrile (50:50, v/v) in an isocratic mode at a flow rate of 0.4 ml/min. The Xevo TQD LC–MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. A full validation of the method was performed according to the FDA guidelines. Linearity was found to be in the range of 0.25–3500 ng/ml for SF and 5–2000 ng/ml for LD. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A short run time of 2 min allows analysis of more than 400 plasma samples per day. The developed method was successfully applied to both fasting and fed bioequivalence studies in healthy human volunteers
Fluid mechanics / Pijush K. Kundu, Ira M. Cohen, David R. Dowling.
No full textengineering bookfair2016Includes bibliographical references and index.xxiv, 921 pages
Simultaneous Determination of Aspirin, Dipyridamole and Two of Their Related Impurities in Capsules by Validated TLC-Densitometric and HPLC Methods
No full textAspirin (ASP) and dipyridamole (DIP) are widely used as a combination in pharmaceutical formulations
for treatment of strokes. Many of these formulations are containing tartaric acid as an excipient
(in DIP pellets formulation for sustained release), which increases the probability of formation of
dipyridamole tartaric acid ester impurity (DIP-I). On the other hand, salicylic acid (SAL) is considered
to be one of the synthesis impurities and a degradation product of ASP. In this work, two chromatographic
methods, namely, TLC-densitometry and HPLC, have been established and validated for
simultaneous determination of ASP, DIP, SAL and DIP-I. Good separation was achieved by using
silica gel as stationary phase and toluene–methanol–ethyl acetate (2:3:5, by volume) as mobile
phase in the case of TLC-densitometry and Zorbax ODS column with mobile phase consisting of
phosphate buffer (pH 3.3)–acetonitrile–triethylamine (40:60:0.03, by volume) for HPLC. Influence
of different organic solvents in mobile phase composition has been studied to optimize the separation
efficiency in TLC densitometry. Moreover, factors affecting the efficiency of HPLC, like pH of the
buffer used, organic solvent ratio in the mobile phase and flow rate, have been carefully studied
using one variable at a time approach. Finally, the proposed methods were validated as per ICH
guidelines
Different camera and light positions to facilitate image analysis processing in rotary drums studies
No full textThis paper represents an extension to our experimental work published
previously in Karali et al., [20]. This new experimental work is mainly
performed to overcome all the technical problems issued by the previous
work like; camera and light positions. In order to facilitate image analysis
processing in rotary drums studies. The experiments are aimed at
determining the optimum loading of a flighted rotary drum (1.0 m
diameter and 0.3 m length). Number of flights of 12 and 18, flight
tangential / radial length ratios of 0.375, 0.75 and in addition 1.0 (for 12
flights only) and rotational speeds of 1, 3 and 5 rpm were researched.
Two materials were examined: quartz sand (0.2 mm) particle diameter
and glass beads (0.7 mm). All of the results from previous work [19, 20]
and the present work are gathered in one correlation describing the filling
degree of a flighted rotary drum as a function of many operating
parameters
Comparative Pharmaceutical Study on Colon Targeted Micro-particles of Celecoxib: In-vitro- Invivo Evaluation
No full textIn order to target celecoxib which is a COX2 inhibitor, with potentials in the prevention and treatment of
colitis and colon cancer, it was formulated as microparticles using solvent /evaporation method and
various pH dependent Eudragit polymers .The in-vitro evaluation of the prepared microparticles showed
spherical and smooth morphology. The encapsulation efficiency and yield were high indicating that the
method used is simple and efficient at this scale. The in-vitro release study showed no release in acidic
medium for 2 hr followed by the release of the drug in pH 6.8 in case of Eudragit L100-55 and L100 and
pH 7.4 in case of Eudragit S100. The pharmacokinetic parameters were calculated and method
validation was performed to insure that it is suitable and reliable. . Pharmacokinetic parameters were
investigated by determining the Cmax, T max , AUC0-t, Kel , and T1/2 of the drug as a suspension and as
microparticles .There was a significant difference (P<0.05) in Tmax between the drug as a suspension
and as microparticles. The effect of celecoxib on the degree of inflammation was examined on acetic
acid induced colitis rat model and the drug was given as a suspension and as microparticles . The
evaluation was done using macroscopical,microscopical and biochemical examination. There was a
significant difference between the acetic acid control group and the treatment groups regarding all
examination criteria in the order microparticles formulated using Eudragit S100 followed by Eudragit
L100-55 while microparticles using Eudragit L100 and drug suspension showed almost the same results
ATINER's Conference Paper Series COM2016-1994
No full textSegmentation is a core process for automatic detection and identification of brain tumors as it plays a vital role in extracting the information of the image as measuring and visualizing the brain's anatomical structures and analyzing the brain changes. From this point the need for accurate and automatic segmentation techniques has risen as manual segmentation is not a realistic solution and yet time consuming. This paper examines the various automated segmentation techniques used by researchers on brain magnetic resonance images (MRI), giving the most important features for the most common techniques used in the area of brain tumors. Moreover, a comparative study to address the differences, limitations, advantages and challenges of each technique mentioned when being used on brain MRI to find out their efficiency in this area and to put guidelines that should be considered when using these techniques. Keywords: Brain Tumors, Magnetic Resonance Images, Machine learning, Segmentation
Solar Photovoltaic System Applications : A Guidebook for Off-Grid Electrification / Parimita Mohanty; Tariq Muneer; Mohan Kolhe
No full textix, 184 p. :Presenting a complete guide for the planning, design and implementation of solar PV systems for off-grid applications, this book features analysis based on the authors' own laboratory testing as well as their in the field experiences. Incorporating the latest developments in smart-digital and control technologies into the design criteria of the PV system, this book will also focus on how to integrate newer smart design approaches and techniques for improving the efficiency, reliability and flexibility of the entire system. The design and implementation of India's first-of its-kind Smart Mini-Grid system (SMG) at TERI premises, which involves the integration of multiple renewable energy resources (including solar PV) through smart controllers for managing the load intelligently and effectively is presented as a key case study. Maximizing reader insights into the performance of different components of solar PV systems under different operating conditions, the book will be of interest to graduate students, researchers, PV designers, planners, and practitioners working in the area of solar PV design, implementation and assessment
Evaluation of Adaptation of Resin Composite Restorations Packed using Ultrasonic Vibration Techniques A Systematic Review
No full textObjectives: The aim of this systematic review was to evaluate the effect of ultrasonic packing techniques using on the adaptation of resin composite materials. Methods: Two electronic databases were searched without limitations through May2015. The terms Bulk packing, Sonic vibration, Dental marginal adaptation, Marginal assessment, Dental leakage, Void, and Composite resins were used. Screening through titles and abstracts was initially performed, and then articles that fulfilled the inclusion criteria were selected for a full-text assessment. Findings: The database search strategy retrieved fifty nine potentially eligible studies. No duplicated studies were found. Titles and abstracts were screened and studies that fulfilled the inclusion criteria were selected for a full-text assessment. Finally fifteen laboratory studies met the inclusion criteria and reference list for them was obtained. Applications/Improvements: Placement technique did not influence the adaptation of resin composite restorations. While the type of resin composite material influenced the extent of marginal adaptation. There is an interaction between the composition of the resin composite material and the application technique. The adaptation of new Sonic Fill system is promising and needs further investigations concerning its clinical longevity
Effect of Antiadherents on the Physical and Drug Release Properties of Acrylic Polymeric Films
No full textAntiadherents are used to decrease tackiness of a polymer coating during both processing and subsequent storage. Despite being a common excipient in coating formulae, antiadherents may affect mechanical properties of the coating film as well as drug release from film-coated tablets, but how could addition of antiadherents affect these properties and to what extent and is there a relation between the physical characteristics of the tablet coat and the drug release mechanisms? The aim of this study was to evaluate physical characteristics of films containing different amounts of the antiadherents talc, glyceryl monostearate, and PlasACRYL(TM) T20. Eudragit RL30D and Eudragit RS30D as sustained release polymers and Eudragit FS30D as a delayed release material were used. Polymer films were characterized by tensile testing, differential scanning calorimetry (DSC), microscopic examination, and water content as calculated from loss on drying. The effect of antiadherents on in vitro drug release for the model acetylsalicylic acid tablets coated with Eudragit FS30D was also determined. Increasing talc concentration was found to decrease the ability of the polymer films to resist mechanical stress. In contrast, glyceryl monostearate (GMS) and PlasACRYL produced more elastic films. Talc at concentrations higher than 25% caused negative effects, which make 25% concentration recommended to be used with acrylic polymers. All antiadherents delayed the drug release at all coating levels; hence, different tailoring of drug release may be achieved by adjusting antiadherent concentration with coating level