Detection Of Digoxin Research Articles

Ultrasensitive serological digoxin fluorescence sensor based on cascade amplification of entropy-driven DNA nanomachine and proximity ligation assay

A nanobiosensor was prepared by DNA nanomachine based on proximity ligation assay (PLA) for the detection of digoxin (DIG) in serum. In this sensor the DNA nanomachine releases a large number of signal probes (SP) after addition of DIG, which participate in PLA as the connector strand, initiating real-time quantitative polymerase chain reaction (qPCR) and producing fluorescence signals. For the benefit of clinical therapeutics, we determined the detection range of 0.1 ∼ 5 ng/mL. Under the optimal experimental conditions, the cycle threshold (Ct) value showed a good linear relationship with DIG concentrations, and the detection limit was as low as 0.06 ng/mL (3σ). This method achieved the ultrasensitive detection of DIG by signal amplification and was successfully used for the detection of DIG in real serum, which has a good potential for application in the field of therapeutic drug monitoring.

Rapid, presumptive identification of seed-based toxins using direct analysis in real time mass spectrometry (DART-MS) and its variants

Detection of seed-based toxins is a need for forensic chemists when suspected poisonings occur. The evidence that is found is often physically unidentifiable, as the seeds are mashed to extract the toxin. This work investigates potential strategies for rapid detection of seed-based toxins and seed mashes containing these toxins using chemical signatures obtained by direct analysis in real time mass spectrometry (DART-MS). Seven toxins (digoxin, digitoxin, hypaconitine, hyoscyamine, lanatoside, oleandrin, and scopolamine) and six seeds containing these toxins were studied. While detection of four of the toxins was readily attainable, detection of digoxin, digitoxin, and lanatoside was hindered by the inability to thermally desorb these larger compounds under normal operating conditions. The use of DART-MS variants capable of higher desorption temperatures (thermal desorption (TD)-DART-MS and infrared thermal desorption (IRTD)-DART-MS) enabled detection of these compounds. Detection of toxins from direct analysis of seed mashes and methanolic seed mash extracts was found to be compound and technique dependent. Principal component analysis (PCA) of generated mass spectra enabled differentiation of seed species, even in cases where the toxins were undetectable.

Endogenous Cardiotonics: Search and Problems.

Medicinal preparations currently used for the treatment of patients with chronic cardiac failure involve those that reduce the heart load (vasodilators, diuretics, beta-blockers, and angiotensin- converting enzyme (ACE) inhibitors). Cardiotonic drugs with the cAMP-dependent mechanism are unsuitable for long-term administration due to the intensification of metabolic processes and an increase in the oxygen demand of the myocardium and all tissues of the body. For many years, digoxin has remained the only preparation enhancing the efficiency of myocardial performance. The detection of digoxin and ouabain in intact animals has initiated a search for other compounds with cardiotonic activity. The review summarizes current data on the effect exerted on the heart performance by endogenous compounds, from simple, such as NO and CO, to steroids, fatty acids, polypeptides, and proteins. Controversial questions and problems with the introduction of scientific achievements into clinical practice are discussed. The results obtained by the authors and their colleagues after many years of studies on the cardiotropic properties of serum lipoproteins are also reported. The experimentally established cardiotonic activity of apoprotein A-1, which is accompanied by a decrease in the relative consumption of oxygen, maybe of great interest.

Designing and construction of genetically encoded FRET-based nanosensor for qualitative analysis of digoxin

Nanobiotechnological improvements defined on the utilization of biological materials and principles have enormously partaken to revolutionize physical, chemical, and biological sciences. However, the exploration of plant nanobiotechnology is still in its outset. The search for novel tools to monitor plant biomolecules is an emerging issue for the nanobiotechnologists. Given this, a genetically encoded FRET-based nanobiosensor has been developed to monitor the popular plant cardiac glycoside – digoxin, which is used as the most common prescription drug for heart-related illnesses across the world. Digoxin is sourced from the leaves of the foxglove plant (Digitalis purpurea L.) and has a significant demand in the medical sector. Moreover, with the rising popularity of the herbal formulations in the global market, attention towards the authentication and quality control of the herbal drugs is important. Furthermore, digoxin has a very narrow therapeutic range, i.e., 0.6 nM - 2.6 nM. Therefore, strict monitoring of blood digoxin levels is necessary. Besides, previously used techniques for drug authentication and quantification of small-molecule drugs in blood samples are not the best choice available. The nanobiosensor is based on the FRET (Fluorescence Resonance Energy Transfer) mechanism, and it is constructed in such a way that it gives a changed FRET output in the presence of digoxin. Two fluorophores, enhanced cyan fluorescent protein (ECFP) and Venus, were attached on either end of the sensory domain - human nuclear receptor ROR-gamma (RORγt). The developed nanobiosensor was named as fluorescent indicator protein for digoxin, (FLIP-digoxin). The ligand binding affinity of FLIP-digoxin was calculated as 425 μM. Affinity mutants of the FLIP-digoxin were also generated to measure digoxin in wide concentration ranges. This sensor offers high-throughput qualitative analysis of digoxin in Digitalis preparations procured from local drug stores. It confirms the authenticity of the preparations through the detection of digoxin. The FLIP-1n was also able to monitor digoxin concentration in serum samples in lesser than 5 min. The nanobiosensor was found pH stable, digoxin-specific, non- interfered by the biological serum species and can perform high throughput screening of the Digitalis powder, infusion and tincture preparations.

A New, High-Throughput High-Performance Liquid Chromatographic/Mass Spectrometric Assay for Therapeutic Level Monitoring of Digoxin in Human Plasma

A new, high-throughput HPLCIMS assay for the quantification of digoxin in human plasma was developed and validated. The separation was performed on a Zorbax SB-C18 column under isocratic conditions using a 55 + 45 (v/v) mixture of methanol and 0.1% (v/v) formic acid in 10 microM sodium acetate as the mobile phase at 45 degrees C with a flow rate of 1 mL/min. The detection of digoxin was performed in the selected ion monitoring mode (m/z 803.5). The human plasma samples (0.2 mL) were deproteinized with 7% perchloric acid in water, and aliquots of 20 microL from supernatants obtained after centrifugation were directly injected into the chromatographic system. The method showed good linearity (r > 0.9926), precision (CV > 18.9%), and accuracy (bias > 5.6%) over the range of 0.5-50 ng/mL plasma. The lower LOQ was 0.5 ng/mL, and the recovery was between 92 and 106%. The method is not expensive, it needs a minimum time for plasma sample preparation, and it has a run time of 2.3 min for instrument analysis (the retention time of digoxin was 1.9 min). The developed and validated high-throughput method is very simple, rapid, and efficient, with wide applications in clinical level monitoring, pharmacokinetics, and bioequivalence studies.

Beneficial Effect of Digoxin-Specific Fab Antibody Fragments in Oleander Intoxication

A 24-year-old man presented to the emergency department with nausea, vomiting, abdominal pain, and an acute confusional state of 6 hours' duration. Ten hours before admission, he had ingested a mixture of orange juice and six ground leaves, later identified as Nerium oleander (common pink oleander) leaves. His blood pressure was 100/80 mm Hg, and his pulse rate was irregular at 40/min. He was disoriented and his speech was dysarthric. Twelve-lead electrocardiography revealed a complete atrioventricular block, with a nodal escape rhythm of 40/min and diffuse ST depression. The presumptive diagnosis of acute oleander intoxication was confirmed by the detection of digoxin (1.0 nmol/L [0.8 ng/mL]) on radioimmunoassay. Despite intensive therapy, the patient's hemodynamic condition deteriorated. His blood pressure decreased to 70/40 mm Hg; he became oliguric and nonresponsive to external stimuli; and his potassium concentration rose to 6.8 mmol/L. Eighteen hours after admission, an empiric 480-mg dose of digoxin-specific Fab antibody fragments was administered intravenously over 30 minutes. Within minutes of the initiation of immunotherapy, the patient woke up; his blood pressure rose to 90/50 mm Hg; and he regained a sinus rhythm of 68/min with a prolonged PR interval. His potassium concentration decreased to 5.1 mmol/L within 15 minutes and normalized within 1 hour of therapy initiation. One day later, the 1 degree atrioventricular block disappeared, but the ST depression persisted for an additional 6 days. The value of digoxin-specific Fab antibody fragments in the treatment of plant glycoside and, in particular, oleander intoxication is discussed.

An improved chemiluminescence-based liposome immunoassay involving apoenzyme.

An improved liposome immunoassay system (LIS) combining the chemiluminescence-based LIS with an apoenzyme reactivation immunoassay system (ARIS) was developed. A low-molecular-weight co-factor, FAD (flavin adenine dinucleotide), was incorporated into liposomes instead of the high-molecular-weight enzyme GOD (glucose oxidase). FAD released from liposomes by cytolysin-hapten conjugates bound to Apo-GOD and regenerated GOD. The system allowed detection of 10 pM digoxin, the model analyte and was linear over 10 pM to 13 nM digoxin. This sensitivity was about 300 times higher than that of the homogeneous system using GOD-containing liposomes and 30 times higher than that of the heterogeneous system which we reported previously. The time required for incubation during the detection of digoxin was reduced from 20 to 3 h.

Detection of digoxin, digitoxin, their cardioactive metabolites and derivatives by high-performance liquid chromatography and high-performance liquid chromatography—radioimmunoassay

High-performance liquid chromatographic (HPLC) systems are described for the separation of the cardioactive metabolites of the digoxin and digitoxin series that are formed by the splitting of digitoxose sugar residues from the aglycone steroid: (1) isocratic separation of digoxin and its cardioactive metabolites; (2) isocratic separation of digitoxin and its cardioactive metabolites; and (3) gradient elution separation of the digoxin and digitoxin series including β-acetyl- and β-methyldigoxin. Separations were performed on a 10-μm bonded octadecyl phase column using various mixtures of acetonitrile—water and acetonitrile—methanol—water as the mobile phase. These methods provide high peak resolution and are well suited for collecting elution fractions, e.g. to link up with sensitive immunological measurements. An HPLC—radioimmunoassay method is described for the quantitation of digoxin, digitoxin and their metabolites in human tissues.

Detection of Digoxin in Bloodstains

Picogram quantities of digoxin were detected in 100-microL samples of dried bloodstains by using radioimmunoassay. The extractability of digoxin by various surfactants and the problems encountered with aged stains were investigated.

Digoxin Concentrations in Fatal Cases

Abstract Analytical methods for the determination of digoxin in pharmaceutical and autopsy specimens using colorimetry [1], gas liquid chromatography [2ߝ4], fluorometry [1,5], and polarography [6] have been reported. These classic methods, however, suffered from lack of sensitivity and specificity in the therapeutic (1.0 to 1.4 μg/litre) [7] and borderline toxic (2.0 μg/litre or greater) ranges, making detection of this drug possible only when large amounts remained unadsorbed in the stomach or excreted via the kidneys. The introduction of radioimmunoassay in 1969 by Smith et al [7] and Smith and Haber [8] made possible the detection of digoxin in postmortem biological fluids and tissue samples. Radioimmunoassay for the determination of serum digoxin is now the most extensively used radioisotope test in many nuclear laboratories and may be the most commonly requested drug assay by hospital physicians.