The use of SDS micelles as additive to increase fluorescence analysis of sitagliptin and saxagliptin derivatives in their tablets and human plasma

2019 ◽  
Vol 146 ◽  
pp. 20-24 ◽  
Author(s):  
Aya Barseem ◽  
Hytham Ahmed ◽  
Yasser El-Shabrawy ◽  
Fathalla Belal
Keyword(s):  
Human Plasma ◽  
Fluorescence Analysis ◽  
Sds Micelles

scholarly journals Spectrofluorometric Determination of Citalopram in Pharmaceutical Preparations and Spiked Human Plasma Using Organized Media

2006 ◽  
Vol 89 (5) ◽  
pp. 1288-1295 ◽  
Author(s):  
Dina T El-Sherbiny
Keyword(s):  
Aqueous Solution ◽  
Human Plasma ◽  
Fluorescence Intensity ◽  
Pharmaceutical Preparations ◽  
Citrate Buffer ◽  
Acidic Aqueous Solution ◽  
Sds Micelles ◽  
Spectrofluorometric Determination ◽  
Organized Media

Abstract The native fluorescence of citalopram (CIT) was (obtained in citrate buffer of pH 6.5 with and without β-cyclodextrin (β-CD) or sodium dodecyl sulfate (SDS) as fluorescence enhancers at 305 nm using 242 nm for excitation. Micellar systems of ionic and nonionic surfactants were investigated by measuring the fluorescence intensity of the analyte-surfactant system. In slightly acidic aqueous solution of pH 6.5, CIT was better incorporated in CDs and SDS micelles. The luminescence emission from CIT was found to be greatly enhanced by SDS micelles. The fluorescence intensity enhancements in CDs medium and in SDS as ionic surfactant relative to slightly acidic aqueous solution were 125 and 250%, respectively. Organized media-enhanced spectroflourometric methods were developed for the determination of CIT, in pure form as well as in pharmaceutical preparations. The fluorescence intensity-concentration plots were rectilinear over the ranges 0.06 to 0.64, 0.04 to 0.40, and 0.02 to 0.26 μg/mL with lower detection limits of 0.02, 0.01, and 0.007 μg/mL, either in citrate buffer only or in β-CD and SDS as organized media, respectively. Furthermore, the high sensitivity attained by using SDS as organized medium allowed in vitro spectrofluorometric determination of CIT in spiked human plasma. Interference from endogenous amino acids has been overcome by using the solid-phase extraction technique; the mean recovery (n = 5) was 100.1 ± 0.8%

An x-ray microprobe based upon a close-coupled focal-spot / glass capillary arrangement

1992 ◽  
Vol 50 (2) ◽  
pp. 1758-1759
Author(s):  
D. A. Carpenter ◽  
M. A. Taylor
Keyword(s):  
Imaging Techniques ◽  
Fluorescence Analysis ◽  
High Sensitivity ◽  
Specimen Preparation ◽  
X Rays ◽  
Glass Capillary ◽  
Close Coupling ◽  
X Ray ◽  
Point To Point ◽  
Beam Damage

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Performances of an Artificial Reagent for the One-stage Factor IX Assay

1975 ◽  
Vol 33 (03) ◽  
pp. 547-552 ◽  
Author(s):  
L Meunier ◽  
J. P Allain ◽  
D Frommel
Keyword(s):  
Human Plasma ◽  
Factor Ix ◽  
Severe Haemophilia ◽  
Normal Human Plasma ◽  
Haemophilia B ◽  
One Stage ◽  
Normal Human ◽  
The One

SummaryA mixture of adsorbed normal human plasma and chicken plasma was prepared as reagent for factor IX measurement using a one-stage method. The substrate was found to be specific for factor IX. Its performances tested on samples displaying factor IX activity ranging from <l%–2,500% compared favorably with those obtained when using the plasma of severe haemophilia B patients as substrate.

Plasma Components which Interfere with Ristocetin-induced Platelet Aggregation

1975 ◽  
Vol 33 (03) ◽  
pp. 540-546 ◽  
Author(s):  
Robert F Baugh ◽  
James E Brown ◽  
Cecil Hougie
Keyword(s):  
Platelet Aggregation ◽  
Human Plasma ◽  
Plasma Proteins ◽  
Binding Protein ◽  
Plasma Heating ◽  
Protein S ◽  
Fold Increase ◽  
Normal Human Plasma ◽  
Preliminary Examination ◽  
Normal Human

SummaryNormal human plasma contains a component or components which interfere with ristocetin-induced platelet aggregation. Preliminary examination suggests a protein (or proteins) which binds ristocetin and competes more effectively for ristocetin than do the proteins involved in ristocetin-induced platelet aggregation. The presence of this protein in normal human plasma also prevents ristocetin-induced precipitation of plasma proteins at levels of ristocetin necessary to produce platelet aggregation (0.5–2.0 mg/ml). Serum contains an apparent two-fold increase of this component when compared with plasma. Heating serum at 56° for one hour results in an additional 2 to 4 fold increase. The presence of a ristocetin-binding protein in normal human plasma requires that this protein be saturated with ristocetin before ristocetin-induced platelet aggregation will occur. Variations in the ristocetin-binding protein(s) will cause apparent discrepancies in ristocetin-induced platelet aggregation in normal human plasmas.

Studies on the Fibrinolytic System in Human Plasma: Quantitative Determination of Plasminogen Activators and Proactivators

1979 ◽  
Vol 41 (02) ◽  
pp. 365-383 ◽  
Author(s):  
C Kluft
Keyword(s):  
Pilot Study ◽  
Plasma Level ◽  
Human Plasma ◽  
Plasminogen Activators ◽  
Venous Occlusion ◽  
Quantitative Information ◽  
Optimal Recovery ◽  
Dextran Sulphate ◽  
Baseline Levels

SummaryEffects due to plasma plasminogen activators and proactivators are usually studied in assay systems where inhibitors influence the activity and where the degree of activation of proactivators is unknown. Quantitative information on activator and proactivator levels in plasma is therefore not availableStudies on the precipitating and activating properties of dextran sulphate in euglobulin fractionation presented in this paper resulted in the preparation of a fraction in which there was optimal recovery and optimal activation of a number of plasminogen activators and proactivators from human plasma. The quantitative assay of these activators on plasminogen-rich fibrin plates required the addition of flufenamate to eliminate inhibitors. The response on the fibrin plates (lysed zones) could be coverted to arbitrary blood activator units (BAU). Consequently, a new activator assay which enables one to quantitatively determine the plasma level of plasminogen activators and proactivators together is introduced.Two different contributions could be distinguished: an activity originating from extrinsic activator and one originating from intrinsic proactivators. The former could be assayed separately by means of its resistance to inhibition by Cl-inactivator. Considering the relative concentrations of extrinsic and intrinsic activators, an impression of the pattern of activator content in plasma was gained. In morning plasma with baseline levels of fibrinolysis, the amount of extrinsic activator was negligible as compared to the level of potentially active intrinsic activators. Consequently, the new assay nearly exclusively determines the level of intrinsic activators in morning plasma. A pilot study gave a fairly stable level of 100 ± 15 BAU/ml (n = 50). When fibrinolysis was stimulated by venous occlusion (15 min), the amount of extrinsic activator was greatly increased, reaching a total activator level of 249 ± 27 BAU/ml (n = 7).

Potentially Thrombogenic Materials in Factor IX Concentrates

1975 ◽  
Vol 33 (03) ◽  
pp. 617-631 ◽  
Author(s):  
H. S Kingdon ◽  
R. L Lundblad ◽  
J. J Veltkamp ◽  
D. L Aronson
Keyword(s):  
Human Plasma ◽  
Antithrombin Iii ◽  
Factor Ix ◽  
In Vitro Assays ◽  
Substantial Agreement ◽  
Coefficient Of Correlation

SummaryFactor IX concentrates manufactured from human plasma and intended for therapeutic infusion in man have been suspected for some time of being potentially thrombogenic. In the current studies, assays were carried out in vitro and in vivo for potentially thrombogenic materials. It was possible to rank the various materials tested according to the amount of thrombogenic material detected. For concentrates not containing heparin, there was substantial agreement between the in vivo and in vitro assays, with a coefficient of correlation of 0.77. There was no correlation between the assays for thrombogenicity and the antithrombin III content. We conclude that many presently available concentrates of Factor IX contain substantial amounts of potentially thrombogenic enzymes, and that this fact must be considered in arriving at the decision whether or not to use them therapeutically.

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