Ultrasonic microdialysis coupled with capillary electrophoresis electrochemiluminescence study the interaction between trimetazidine dihydrochloride and human serum albumin

Screen‐printed electrochemical sensors for label‐free potentiometric and impedimetric detection of human serum albumin

Herein, two electrochemical methods based on potentiometric and impedimetric transductions were presented for albumin targeting, employing screen‐printed platforms (SPEs) to make easy and cost‐effective sensors with good detection merits. The SPEs incorporated ion‐to‐electron multi‐walled carbon nanotubes (MWCNTs) transducer. Sensors were constructed using either tridodecyl methyl‐ammonium chloride (TDMACl) (sensor I) or aliquate 336S (sensor II) in plasticized polymeric matrices of carboxylated poly (vinyl chloride) (PVC‐COOH). Analytical performances of the sensors were evaluated using the above‐mentioned electrochemical techniques. For potentiometric assay, constructed sensors responded to albumin with −81.7 ± 1.7 (r2 = 0.9986) and −146.2 ± 2.3 mV/decade (r2 = 0.9991) slopes over the linearity range 1.5 μM–1.5 mM with 0.8 and 1.0 μM detection limits for respective TDMAC‐ and aliquate‐based sensors. Interference study showed apparent selectivity for both sensors. Impedimetric assays were performed at pH = 7.5 in 10 mM PBS buffer solution with a 0.02 M [Fe(CN)6]−3/−4 redox‐active electrolyte. Sensors achieved detection limits of 4.3 × 10−8 and 1.8 × 10−7 M over the linear ranges of 5.2×10−8–1.0×10−4 M and 1.4×10−6–1.4×10−3 M, with 0.09 ± 0.004 and 0.168 ± 0.009 log Ω/decade slopes for sensors based on TDMAC and aliquate, respectively. These sensors are characterized with simple construction, high sensitivity and selectivity, fast response time, single‐use, and cost‐effectiveness. The methods were successfully applied to albumin assessment in different biological fluids.

The first spectrofluorimetric approach for accurate determination of trimetazidine in its dosage forms: Application to content uniformity testing

A novel sensitive and simple spectrofluorimetric method has been developed then validated for the determination of trimetazidine in pure form and its tablets. This method is found on the reaction between trimetazidine's secondary amine moiety with NBD-Cl reagent, using borate buffer at pH 8.0 yielding a highly fluorescent product whose fluorescence intensity was measured at 526 nm (excitation at 466 nm). A calibration curve plotted showed that the linear range of the presented method was (50-700 ng/ml) with a correlation coefficient of 0.9998. The limits of detection (LOD) and limits of quantitation (LOQ) values were 15.01 and 45.50 ng/ml respectively. The presented approach was validated according to ICH guidelines and successfully applied for determining trimetazidine in its tablets with a mean percentage recovery of 99.65% ± 1.04, 99.23% ± 0.80 and 98.33% ± 1.03 for Metacardia® (20 mg), Vastor ® (20 mg) and Tricardia® (20 mg) tablets respectively. Finally, the proposed method was adopted to study the content uniformity test according to USP guidelines.

Sample preparation techniques for protein binding measurement in radiopharmaceutical approaches: A short review

Plasma protein binding (PPB) measurement is a key step in radiopharmaceutical studies for the development of positron emission tomography (PET) radioligands. PPB refers to the binding degree of a radioligand, radiotracer, or drug to blood plasma proteins or tissues after administration into the body. Several techniques have been successfully developed and applied for PPB measurement of PET radioligands. However, there is room for progress among these techniques in relation to duration time, adaptability with nonpolar radioligands, in vivo measurement, specificity, and selectivity. This mini review gives a brief overview of advances, limitations, and prospective applications of commercially-available PPB methods.

Enhanced light-emitting diode induced fluorescence detection system with capillary electrophoresis

An enhanced fluorescence detection system of capillary electrophoresis (CE) was equipped with a concave silver mirror, by which the detection sensitivity of light-emitting diode induced fluorescence (LEDIF) can be increased greatly. The silver concave mirror and the cathode window in photomultiplier tube (PMT) were accurately set face to face at the same axis. When the two labeled tumor markers exactly moved to the center of detection window, the emission from analytes are excitated by LED source. Currently, the analytes may be regarded as a luminescent source point. When the source point exactly moves to the focus of the concave mirror, the emission of the labeled sample was collected effectively, enhanced by convergence and reflected by the concave mirror. Then it was sensitively detected by the PMT. The optical mechanism of enhancing detection sensitivity was explored. A simple comparative test on sensitivity was carried out, which aimed to compare sensitivity of the new detection system with concave mirror to that without concave mirror but the other conditions were kept the same. Two tumor markers labeled with FITC were selected for the test, using the simple LEDIF detect system. The results (LOD, 150 nM for L-Leu and L-Val) showed that the detection sensitivity matched with concave mirror reached more 16 times than the detection method without concave mirror.

Simultaneous determination of chlortetracycline, ampicillin and sarafloxacin in milk using capillary electrophoresis with electrochemiluminescence detection

A fast, inexpensive and sensitive approach for the simultaneous determination of chlortetracycline, ampicilline and sarafloxacin in milk was developed using capillary electrophoresis coupled with an electrochemiluminescence detector. Under the optimal detection conditions, the linear ranges for chlortetracyline, ampicilline and sarafloxacin were 0.030-5.0, 0.050-5.0 and 0.0040-2.0 μg ml^-1, respectively. The correlation coefficients of chlortetracycline, ampicilline and sarafloxacin were determined as 0.9997, 0.9952 and 0.9978, respectively. Detection limits (S/N = 3) of chlortetracycline, ampicilline and sarafloxacin were found as 0.017, 0.018 and 0.0013 μg ml^-1, respectively. This method was successfully applied for the determination of chlortetracycline, ampicilline and sarafloxacin in milk. The recoveries were between 95.3% and 100%. The relative standard deviations of the detection limit and recovery were less than 2.6% and 3.2%, respectively.

Sensitive CE-ECL method with AuNPs-enhanced signal for the detection of β-blockers and the study of drug–protein interactions

A sensitive capillary electrophoresis (CE) system coupled with electrochemiluminescence (ECL) of tris(2,2′-bipyridyl) ruthenium (ii) is described for the detection of propranolol (Pro) and acebutolol (Ace).

Binding mechanism of nine N-phenylpiperazine derivatives and α1A-adrenoceptor using site-directed molecular docking and high performance affinity chromatography

Investigating the binding mechanism of α_1A-adrenoceptor and its specific ligands by affinity chromatography.