Highly Sensitive Fluorescence Methods for the Determination of Alfuzosin, Doxazosin, Terazosin and Prazosin in Pharmaceutical Formulations, Plasma and Urine

Utilization of a micellar matrix for simultaneous spectrofluorimetric estimation of alfuzosin hydrochloride and vardenafil hydrochloride

A sensitive and direct spectrofluorimetric method was developed for simultaneous quantitation of two co-administered drugs, namely, alfuzosin hydrochloride (AFH) and vardenafil hydrochloride (VRH). Both drugs exhibited native fluorescence properties that could be exploited to assay them in biological fluids with high sensitivity. Spectrofluorimetric analysis of AFH and VRH is based on excitation of both drugs at 265 nm where emission spectra were recorded separately for AFH and VRH at 380 and 485 nm, respectively. Micellar trends in analytical chemistry were adopted to minimize both environmental and occupational hazards, using distilled water and sodium dodecyl sulphate (serves as a micellar medium that enhanced the sensitivity of AFH and VRH) for analysis of both drugs in their raw materials, tablets, and human biological fluids (plasma and urine). Linearity ranges were 1.0-16.0 and 10.0-700.0 ng mL^-1 for AFH and VRH, respectively. The proposed method was successfully assessed for analysis of AFH and VRH in spiked human plasma and urine samples over the following concentrations: 1.0-12.0 ng mL^-1 and 4.0-400.0 ng mL^-1 for both drugs, simultaneously with mean recoveries of 101.08 % and 102.06 % in plasma and 96.75 % and 92.8 % in urine. Statistical analysis of the practical results has proved quite good agreement and revealed there were no significant differences in the accuracy and precision with those obtained by the comparison methods. The proposed method was applied successfully to Prostetrol® and Powerecta® commercial tablets without interference with tablet additives.

Simple and fast LC-MS/MS method for quantification of terazosin in human plasma and application to bioequivalence study

A simple, fast and sensitive LC-MS/MS method was developed to quantify terazosin in human plasma. The mobile phase consisted of acetonitrile-0.1% (v/v) formic acid (70:30, v/v). Prazosin was used as internal standard (IS). As deproteinization agent, acetonitrile produced a clean sample. A higher response intensity with more symmetrical peak was obtained using Agilent Poroshell 120 EC-C18 - Fast LC column (100 × 2.1mmID, 2.7 μm) compared with Kinetex XB-C18 (100 × 2.1 mm, 2.6 µm) column. The response of terazosin and IS were approximately two times in citrate phosphate dextrose (CPD) plasma compared with dipotassium ethylenediaminetetraacetic acid (K₂EDTA) plasma. Plasma calibration curve was linear from 1.0 to 100.0 ng/mL, with coefficient of determination r² ≥ 0.99. The within-run and between-run precision values (CV, %) were <5.2% and <7.8%, while accuracy values were 102.8-112.7% and 103.4-112.2%. The extended run accuracy was 98.6-102.8% and precision (CV, %) 4.3-10.4%. The recovery of analyte was >98% and IS >94%. Terazosin in plasma kept at benchtop was stable for 24 h, in autosampler tray for 48 h, in instrumentation room for 48 h, for 7 freeze-thaw cycles and in freezer for 140 days. Terazosin and IS stock standard solutions were stable for 140 days at room temperature and in the chiller. The high throughput method was successfully utilized to measure 935 samples in a bioequivalence study of terazosin.

Mending the fluorescence of two α-blockers through a semiquinoid formation: Hyphenated with experimental design optimization

Herein, a selective and rapid spectrofluorimetric method coupled with experimental design approach for reliable and efficient determination of two α-blockers, namely: terazosin hydrochloride (TER) and doxazosin mesylate (DOX) in their marketed tablets was developed. The presented method adopts formation of a semi-quinoid form of the studied drugs in borate buffer. The effects of parameters influencing fluorescence intensity including pH, the volume of buffer and diluting solvent were optimized using an experimental design methodology. The optimum conditions were found to be pH: 9.8, the volume of buffer: 2.0 mL and diluting solvent: water. Under the optimum experimental conditions, a large enhancement of the studied drugs fluorescence was obtained, measured at 387 after excitation at 246 nm for either TER or DOX with limits of detection 0.05 and 0.14 ng mL^-1 and limits of quantification 0.14 and 0.43 ng mL^-1 in the concentration ranges of 0.2-30.0 ng mL^-1 and 0.5-30.0 ng mL^-1 for TER and DOX, respectively. The presented method was validated according to the ICH guidelines. Furthermore, it extended to perform the content uniformity testing and analysis of the studied drugs in spiked human plasma with % recovery (96.00 ± 0.45-101.42 ± 1.20%, n = 3).

Preconcentration and Detection of Gefitinib Anti-Cancer Drug Traces from Water and Human Plasma Samples by Means of Magnetic Nanoparticles

Along of widespread application of anti-cancer drug Gefitinib (GEF), it appears in human body fluids as well as clinical wastewater. Consequently, a reliable and easy-to-adapt detection technique is of essential importance to quantify the drug in different media. The extraction and quantitative detection of anti-cancer drug Gefinitib (GEF) is demonstrated based on a straightforward and efficient magnetic nanoparticle-assisted preconcentration route from water and human plasma samples. Iron oxide magnetic nanoparticles (Fe₃O₄) have been prepared with an average particle size of 15 nm and utilized as extractible adsorbents for the magnetic solid-phase extraction (MSPE) of GEF in aqueous media. The method is based on MSPE and preconcentration of GEF followed by High-Performance Liquid Chromatography-Ultraviolet Detection (HPLC-UV). The yield of GEF extraction under the optimum MSPE conditions were 94% and 87% for water and plasma samples, respectively. The chromatographic separation was carried out isocratically at 25 °C on a Phenomenex C8 reversed phase column (150 mm × 4.6 mm, with 5 µm particle size). The proposed method was linear over concentration ranges of 15.0–300.0 and 80.0–600.0 ng/mL for water and plasma samples with limits of detection of 4.6 and 25.0 ng/mL in a respective order. Relative standard deviations (%RSD) for intra-day and inter-day were 0.75 and 0.94 for water samples and 1.26 and 1.70 for plasma samples, respectively. Using the magnetic nanoparticles (MNPs) as loaded drug-extractors made the detection of the anti-cancer drug environmentally friendly and simple and has great potential to be used for different drug-containing systems.

An efficient spectrofluorimetric method adopts doxazosin, terazosin and alfuzosin coupling with orthophthalaldehyde: Application in human plasma

A new, selective and sensitive spectrofluorimetric method was designed for the quantitation of doxazosin (DOX), terazosin (TER) and alfuzosin (ALF) in their dosage forms and human plasma. The method adopts efficient derivatization of the studied drugs with ortho-phthalaldehyde (OPA), in the presence of 2-mercaptoethanol in borate buffer (pH9.7) to generate a highly fluorescent isoindole derivatives, which can strongly enhance the fluorescence intensities of the studied drugs, allowing their sensitive determination at 430nm after excitation at 337nm. The fluorescence-concentration plots were rectilinear over the ranges (10.0-400.0) ng/mL. Detection and quantification limits were found to be (0.52-3.88) and (1.59-11.76) ng/mL, respectively. The proposed method was validated according to ICH guidelines, and successfully applied for the determination of pharmaceutical preparations of the studied drugs. Moreover, the high sensitivity of the proposed method permits its successful application to the analysis of the studied drugs in spiked human plasma with % recovery (96.12±1.34-100.66±0.57, n=3). A proposal for the reaction mechanism was presented.

The multicomponent Debus–Radziszewski reaction in macromolecular chemistry

The well-known Debus–Radziszewski reaction is over one century old. However, this reaction has only been considered very recently as a new tool to design original imidazole and imidazolium-containing polymers by direct formation of the imidazole ring during the polymerization process. This article reports recent advances concerning the use of this newly emerging reaction in macromolecular chemistry.

Synthesis of magnetic polymeric ionic liquid nanocomposites by the Radziszewski reaction

The application of the Radziszewski reaction is proposed for the first time for the synthesis of magnetic polymeric ionic liquids. After their characterization, the sorption ability of the nanocomposites towards acidic compounds have been evaluated.