Development of an enzyme-linked immunosorbent assay for the quantification of amiodarone

Analytical Methods for Furanochromone Natural Product, Khellin and Its Inspired Drug Candidates, Amiodarone and Sodium Cromoglycate

Khellin is the key furanocoumarin of Ammi visnaga L. (Lam.) that exhibits various biological properties. This unique natural product has inspired the discovery of two first-in-class drugs, amiodarone and sodium cromoglycate. A wide range of analytical methods were generated while translating khellin scaffold into clinically used drugs; however, they have never been reviewed and critically assessed. The present review aims to review and evaluate the analytical techniques for the natural products, khellin, visnagin, and their inspired drugs, amiodarone and sodium cromoglycate. High-performance liquid chromatography (HPLC) is the extensively used technique in most analytical methods reported for these compounds; however, other techniques including the fluorimetry, luminescence spectrophotometry, potentiometry, voltammetry, FT-Raman spectroscopy, and ELISA were also employed. The review will be helpful for further basic and translational research on furanochromone and related scaffolds.

In Situ Liquid-Phase-Adsorption Measurement System Based on Fiber-Optic Sensing with the Aid of Membranes

At present, liquid phase adsorption (LPA) is still being quantitatively characterized in the way of manual sampling and off-line determination because of the complexity of the system comparing to gas adsorption. This paper describes a novel method for in situ, real-time measurement of LPA in general based on fiber-optic sensing (FOS) with the aid of membranes for the first time. A self-made measurement vessel was assembled from an adsorption bag, thermostatic devices with a stirrer, and a fiber-optic dipping probe. Also, macroporous adsorption resins (MARs) and rutin were chosen as model adsorbent and adsorbate to establish the FOS system. Here, in situ light absorption measurement was achieved by eliminating interference of adsorbent particles via encapsulating them with a membrane into the adsorption bag. In situ LPA measurement of rutin solution on MARs was obtained by detecting light absorption at 353 nm using dipping probe, in the broad concentration range from 0.3 to 60 mg/L with excellent linearity (R ² = 0.9996). In situ measurements of adsorption and desorption kinetics on five kinds of MARs with different polarities were systematically carried out, showing that the adsorption process obeyed the pseudo-second-model. As well as, the system was proved to be highly accurate and reproducible. More importantly, this method enabled to study the initial stage of the adsorption process, starting from the time of the first second, which is the most important part in the adsorption kinetics, and this is impossible for traditional sampling methods. The successful application of FOS to in situ measurement of LPA not only contributes to fast, automatic, and real-time monitoring of LPA process but also enriches the research connotation of adsorption.

Quantification of Cibenzoline by Enzyme-Linked Immunosorbent Assay

We have developed an enzyme-linked immunosorbent assay (ELISA) suitable for routine monitoring of serum levels of cibenzoline. Anti-cibenzoline antibody was obtained by immunizing rabbits with cibenzoline conjugated with bovine serum albumin using N-(4-maleimidobutyryloxy)succinimide as a heterobifunctional coupling agent. An enzyme marker was prepared by coupling 2,2-diphenylethylamine with beta-D-galactosidase using glutaraldehyde. The detection limit of cibenzoline by ELISA was approximately 640 pg/ml with 50-microl samples. Cross-reactivity data showed that the antibody well recognizes both the diphenyl and cyclopropyl moieties, and is thus specific enough to the structure of cibenzoline. The values for the cibenzoline concentrations detected using this assay were comparable with those detected using HPLC. There was a good correlation between the values determined by the two methods. Moreover, ELISA was about 15-fold more sensitive in detecting cibenzoline at lower concentrations. Using this assay, drug levels were easily measured in the serum of rabbits after oral administration of cibenzoline at a single dose of 3 mg/kg.

Establishment of an Enzyme-Linked Immunosorbent Assay for Measurement of Sotalol

We have established an enzyme-linked immunosorbent assay suitable for routine monitoring of serum levels of sotalol. Anti-sotalol antibody was obtained by immunizing rabbits with sotalol conjugated with bovine serum albumin using the N-succinimidyl ester method. An enzyme marker was similarly prepared by coupling sotalol with beta-D-galactosidase. The detection limit of sotalol by the enzyme-linked immunosorbent assay was approximately 32 ng/ml with 50-microl samples. This assay was specific for sotalol because of very slight cross-reactivity with 4-(methanesulfonylamino)benzonitrile (1.6%), but none with D,L-isoproterenol. Using this assay, drug levels were easily measured in the serum of rabbits after oral administration of sotalol at a single dose of 3 mg/kg. The enzyme-linked immunosorbent assay should be a valuable tool in therapeutic drug monitoring and pharmacokinetic studies of sotalol.