Green spectrophotometric and spectrofluorimetric determination of biperiden hydrochloride using erythrosine B sensing probe.

Erythrosine B (EB) is a food colorant antiviral xanthene dye that has many applications as a color additive in pharmaceuticals and cosmetics. Its use as a sensor for spectrofluorimetric and spectrophotometric analysis of amine-based pharmaceuticals renders many advantages because of its availability, low cost, rapid labeling, and high sensitivity. Herein, two fast and sensitive spectrofluorimetric and spectrophotometric methods were established for the estimation of the anti-Parkinson drug, biperiden (BIP) hydrochloride (HCl), in its raw material and tablet forms. The proposed methods depended on the interaction between the phenolic group of EB and the tertiary amino group of the studied analyte to form an ion-pair complex at pH 4 using the Britton Robinson buffer. The spectrofluorimetric method is based on the measurement of the quenching power of BIP HCl on the fluorescence intensity of EB at λex/em = 527.0/550.9 nm. This method was rectilinear over the concentration range of 0.1-1.0 µg/mL with a limit of detection (LOD) = 0.017 µg/mL and a limit of quantification (LOQ) = 0.05 µg/mL. Meanwhile, the colorimetric method involved monitoring the absorbance of the formed ion-pair complex at 555 nm, showing a linearity range of 0.4-5.0 µg/mL with LOD = 0.106 µg/mL and LOQ = 0.322 µg/mL. The proposed methods were assessed for the greenness, indicating the greenness of the developed methods.

SERS study of classical and newly ß-lactams-metal complexation based on in situ laser-induced coral reefs-like silver photomicroclusters: In vitro study of antibacterial activity.

The influence of metal complexation of two polar ß-lactam antibiotics was investigated using surface enhanced Raman spectroscopy (SERS) technique. SERS method was applied to track the structural changes and the degradation behaviour of the studied compounds upon Zinc (II) ions-complexation. In situ laser-induced coral reefs-like photomicroclusters have been utilized as a SERS platform. The produced coral reefs-like photomicroclusters were characterized using scanning electron microscopy (SEM) and transmission electron microscope (TEM). The antibacterial efficiency of the antibiotics was investigated and compared before and after metal complexation using two techniques; agar well diffusion and growth curve. To provide a detailed elucidation of the complexation reaction, mass fragmentation of metal- antibiotics complexes was investigated using liquid chromatography/mass spectrometric (LC/MS) technique. It was found that metal complexation of classical ß-lactam antibiotic (Ticarcillin) promoted the rate of its degradation, leading to a decrease of the antibacterial efficiency. On the other side, the antibacterial activity of the newly developed ß-lactam (Faropenem) has been greatly enhanced via metal-complexation reaction.

New ecological first derivative synchronous spectrofluorimetric method for simultaneous quantification of carvedilol and ivabradine in tablets.

A new, rapid, selective, green, and highly sensitive method has been established to determine ivabradine and carvedilol simultaneously. The first derivative synchronous spectrofluorimetric approach was applied for the determination of the studied drugs. Assessment of the first derivative amplitude of carvedilol and ivabradine has been done at 339 nm and 298 nm respectively which are the zero crossing points of each other. The method validation is estimated and was found to be consistent with International Conference on Harmonization guidelines. Linearity was found to be in the range of 10.0 to 90.0 ng/mL for carvedilol and from 80.0 to140.0 ng/mL for ivabradine. The detection limits were found to be 1.2 ng/ mL and 3.3 ng/mL and the quantitation limits were 3.7 ng / mL and 10.0 ng /mL for carvedilol and ivabradine, respectively. The method was effectively applied for the determination of both drugs in their synthetic mixture in different ratios and in their prepared co-formulated tablets. The results were compared with those of comparison HPLC methods. Ethanol was used as a green solvent. The proposed method is suitable for the determination of ivabradine and carvedilol with satisfactory accuracy and precision. The greenness of the method was evaluated using four assessment tools, i.e. NEMI, GAPI, Eco-scale, and AGREE. The proposed method is simple with a low cost compared to HPLC methods.

First derivative synchronous spectrofluorimetric analysis of bisoprolol fumarate and ivabradine in pharmaceutical and biological matrices. Investigation of the method greenness.

A novel, facile, rapid, and precise synchronous spectrofluorimetric method was evolved for the simultaneous estimation of bisoprolol fumarate and ivabradine in dosage forms and biological fluids. The estimation is based on measuring the first derivative of the synchronous fluorescence spectra of ivabradine and bisoprolol fumarate in ethanol at Δλ = 80 nm. The peak amplitudes are measured at 234.4 nm (zero-crossing point of ivabradine) and 244.0 nm (zero-crossing point of bisoprolol fumarate) to simultaneously analyze bisoprolol fumarate and ivabradine, respectively. The spectrofluorimetric method was optimized by investigating different solvent systems, pH values, and surfactants. The proposed method was linear over concentration ranges 30.0-200.0 ng/ml and 30.0-180.0 ng/ml for ivabradine and bisoprolol fumarate, respectively with detection limits of 4.88 and 5.28 ng/ml. The developed method was used for individual assay of the studied compounds in their pharmaceutical dosage forms with high percentage recoveries. Moreover, the method was applied to analyze ivabradine and bisoprolol fumarate in spiked human urine with percentage recoveries of 99.98 ± 1.16 and 99.95 ± 1.96 for ivabradine and bisoprolol fumarate, respectively. The method greenness was also investigated by Analytical GREEnness (AGREE), Analytical Eco-Scale, and Green Analytical Procedure Index (GAPI) metrics, which ensured the ecofriendship of the proposed method.

Determination of three antiepileptic drugs in pharmaceutical formulations using microfluidic chips coupled with light-emitting diode induced fluorescence detection.

In this study, a facile, sensitive, and precise lab-on-a-chip electrophoretic method coupled with light-emitting diode induced fluorescence (LED-IF) detection was developed to assay three antiepileptic drugs, namely, vigabatrin, pregabalin, and gabapentin, in pharmaceutical formulations. The analytes were derivatised offline for the first time with fluorescine-5-isothiocyanate (FITC) to yield highly fluorescent derivatives with λex/em of 490/520nm. The FITC-labelled analytes were injected, separated, and quantitated by a microfluidic electrophoresis device using fluorescence detection. The labelled analytes were monitored using a blue LED-IF system. The separation conditions were significantly optimised adding specific concentrations of heptakis-(2,6-di-O-methyl)-ß-cyclodextrin (HDM-ß-CD) and methylcellulose to the buffer solution (40mM borate buffer). HDM-ß-CD acted as a selective host for the studied antiepileptic drugs, rendering a high separation efficiency. Methylcellulose was used as an efficient dynamic coating polymer to prevent the labelled drugs from being adsorbed on the inner surfaces of the poly (methylmethacrylate) microchannels. A laboratory-prepared ternary mixture of the three antiepileptic drugs was separated within 100s with acceptable resolution between all the three analytes (Rs>3) and a high number of theoretical plates (N) for each analyte (N≈106 plates/m). The sensitivity of the method was enhanced approximately 80-fold by stacking to yield a detection limit below 0.6ngmL-1 in the concentration range of 2.0-200.0ngmL-1. The method was successfully validated for analysing the studied drugs in their pharmaceutical formulations.

Sustainable environment-friendly quantitative determination of three anti-hyperlipidemic statin drugs and ezetimibe in binary mixtures by first derivative Fourier transform infrared (FTIR) spectroscopy.

FTIR spectrometry is considered a sustainable green analytical chemistry procedure. Its use in quantitative analysis of pharmaceutical compounds in their raw resources and in their dosage forms is growing currently. The current research offers an environment-friendly, speedy, cost-effective, reliable and easy method for the simultaneous estimation of anti-hyperlipidemic drugs. No sample preparation was required except for grinding and mixing with KBr for making pellets used for acquisition of the FT-IR spectra. First-derivative FTIR spectroscopy is used to assess quantitatively atorvastatin (ATR), rosuvastatin (RSV) and simvastatin (SMV) in their binary mixtures with ezetimibe (EZT). For the first mixture, EZT and ATR were determined at 1733.18 cm-1 and 1647.74 cm-1, respectively. In the second mixture, the zero-crossing wave numbers selected for the determination of EZT and RSV were 1733.18 cm-1 and 955.69 cm-1, correspondingly. Whereas, the third mixture was quantified at the wavenumbers of 1520.93 and 3569.68 cm-1 for EZT and SMV, respectively. Validation of the procedure has been performed complying with recommendations of the International Conference of Harmonization (ICH) presenting linearity, accuracy, precision, robustness and selectivity. The linear range for all drugs was 2-30 mg/g. It was found that the LOD was 0.607, 0.311, 0.491 and 0.395 mg/g and the LOQ was found to be 1.839, 0.942, 1.490 and 1.190 mg/g for EZT, ATR, RSV, and SMV, correspondingly. The proposed technique was found to be accurate and precise in terms of percentage error and percentage relative standard deviation among intraday and interday measurements. It was also found selective through comparison of the results of standard drugs with results of binary mixtures and of pharmaceutical tablets. It was found robust through making slight variations in the working conditions and the results obtained remained statistically equivalent. The technique was applied effectively for the estimation of the binary mixtures under study in their tablets. Comparing the found outcomes to those of reference derivative UV spectrophotometric methods gave no significant difference between them. Analytical eco-scale and the scale of Green Analytical Procedure Index (GAPI) are the two scales utilized for evaluation of the greenness of the technique and it was found to be excellent green.

Stacking-cyclodextrin-microchip electrokinetic chromatographic determination of gabapentinoid drugs in pharmaceutical and biological matrices.

A facile, rapid, and highly sensitive microchip-based electrokinetic chromatographic method was developed for the simultaneous analysis of two gabapentinoid drugs, gabapentin (GPN) and pregabalin (PGN). Both drugs were first reacted with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) via nucleophilic substitution reactions to yield highly fluorescent products with λex/em 470/540nm. Analyses of both fluorescently labeled compounds were achieved within 200s in a poly(methyl methacrylate) (PMMA) microchip with a 30mm separation channel. Optimum separation was achieved using a borate buffer (pH 9.0) solution containing methylcellulose and ß-cyclodextrin (ß-CD) as buffer additives. Methylcellulose acted as a dynamic coating to prevent adsorption of the studied compounds on the inner surfaces of the microchannels, while ß-CD acted as a pseudo-stationary phase to improve the separation efficiency between the labeled drugs with high resolution (Rs>7). The fluorescence intensities of the labeled drugs were measured using a light emitting diode-induced fluorescence detector at 540nm after excitation at 470nm. The sensitivity of the method was enhanced 14- and 17-fold for PGN and GPN, respectively by field-amplified stacking relative to traditional pinched injection so that it could quantify 10ngmL-1 for both analytes, with a detection limit lower than 3ngmL-1. The developed method was efficiently applied to analyze PGN and GPN in their pharmaceutical dosage forms and in biological fluids. The extraction recoveries of the studied drugs from plasma and urine samples were more than 89% with%RSD values lower than 6.2.

Application of π acceptors to the spectrophotometric and spectrofluorimetric determination of vincamine and naftidrofuryl oxalate in their pharmaceutical preparations.

Three different spectrophotometric and two spectrofluorimetric methods have been developed and validated for the determination of vincamine (VN) and naftidrofuryl oxalate (NF) in tablets. The spectrophotometric methods depend on charge transfer complex formation between each of VN and NF with 7,7,8,8-tetracyano-quinodimethane (TCNQ), 2,6-dichloroquinone-4-chloroimide (DCQ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) at 843, 580 and 588 nm, respectively. The spectrofluorimetric methods are based on the formation of charge transfer complex between each of the two drugs and TCNQ, with measurement of the fluorophore formed at 312/375 and 284/612 nm, respectively, or with DDQ at 400/475 and 284/396 nm, respectively. In the spectrophotometric measurements, Beer's law was obeyed at concentration ranges of 1.5-16, 10-180 and 12-140 µg/ml for VN with TCNQ, DCQ, and DDQ, respectively. For NF, the corresponding concentrations were 2-28, 5-75 and 25-150 µg/ml with TCNQ, DCQ, and DDQ, respectively. In the spectrofluorimetric measurements, the ranges for VN were 0.05-0.9 and 0.3-4 µg/ml with TCNQ and DDQ, respectively, whereas for NF the ranges were 0.05-0.85 and 0.5-8 µg/ml with TCNQ and DDQ, respectively. The different experimental parameters affecting the development and stability of the formed color or fluorophore were studied and optimized and the molar ratios of the complexes were calculated. The proposed methods were validated according to ICH guidelines and were successfully applied for the determination of VN and NF in their tablet dosage forms.