Green fitted second derivative synchronous spectrofluorometric method for simultaneous determination of remdesivir and apixaban at Nano gram scale in the spiked human plasma

An eco-friendly one-pot spectrofluorimetric approach for the facile determination of overactive bladder drug, tolterodine: Application to dosage forms and biological fluids

Tolterodine tartrate (TTD) was the first antimuscarinic medication developed exclusively for the treatment of overactive bladder syndrome and was approved by the FDA in 1998. As a result of the drug's extensive utilization within the local community following its authorization, there is a pressing need to develop and validate a spectrofluorometric method that is economically efficient, easily reproducible, environmentally sustainable, and possesses high sensitivity. The developed approach relies on enhancing the fluorescence intensity of TTD to reach a level 720 % higher than its initial value, achieved through the application of an aqueous sodium dodecyl sulfate (SDS) solution. A strong correlation was observed with a correlation coefficient of 0.9998 between the concentration of TTD and the fluorescence intensity within the range of 25.0-500.0 ng mL-1. This approach could be employed to quantify TTD in its pure form and to examine pharmaceutical tablets for the purposes of verifying uniform content. Additionally, it was utilized for the evaluation of TTD concentrations in spiked human plasma.

Determination of remdesivir in human plasma using (deep eutectic solvent-ionic liquid) ferrofluid microextraction combined with liquid chromatography

A microextraction technique based on ferrofluids was developed for the preconcentration and quantification of Remdesivir in human plasma samples. This method utilized a new type of magnetic colloids created by combining silica-coated magnetic particles with modified ionic liquid and natural hydrophobic deep eutectic solvent as the carrier liquid. The efficiency of the sorption and desorption steps was optimized using a chemometrics approach. Under the optimized conditions, the calibration curve exhibited linearity in the concentration range of 0.5 to 500.0 μg L-1, with a limit of detection and quantification of 0.2 and 0.5 μg L-1, respectively. The method precision was evaluated by assessing intra- and interday precision at three different analyte concentrations, yielding values of 8.9% and 16.8%, respectively. Moreover, the method accuracy fell within the range of 90.9% to 107.5%. This proposed method offers a green and environmentally friendly sample preparation technique for conducting pharmacodynamic, pharmacokinetic, and therapeutic drug monitoring studies of Remdesivir in biological fluids. Importantly, this technique eliminates the need for external energy sources or the use of dispersive solvents, providing a more efficient and sustainable approach.

Coupling of synchronous fluorescence spectroscopy with derivative amplitude outcomes for simultaneous determination of metoprolol succinate and olmesartan medoxomil in combined pharmaceutical preparation: Application in spiked human plasma

For the first time a spectrofluorimetric method had been achieved for the concurrent analysis of metoprolol succinate (MET) and olmesartan medoxomil (OLM). The approach depended on assessing the first order derivative (¹D) of the synchronous fluorescence intensity of the two drugs in aqueous solution at Δλ of 100 nm. The amplitudes of ¹D at 300 nm and 347 nm were measured for MET and OLM, respectively. The linearity ranges were 100-1000 ng/mL and 100-5000 ng/mL for OLM and MET, respectively. This approach is uncomplicated, repetitive, quick, and affordable. The results of analysis had been statistically verified. The validation assessments were carried out following the recommendations of The International Council for Harmonization (ICH). This technique could be employed to assess marketed formulation. The method was sensitive with limits of detection (LOD) of 32 ng/ml and 14 ng/mL for MET and OLM, respectively. Limits of quantitation (LOQ) were 99 ng/ml for MET and 44 ng/mL for OLM. So it can be applied to determine both drugs in spiked human plasma within the linearity ranges of 100-1000 ng/mL for OLM and 100-1500 ng/mL for MET.

Development and validation of method for analysis of favipiravir and remdesivir in volumetric absorptive microsampling with ultra high-performance liquid chromatography-tandem mass spectrophotometry

Favipiravir and remdesivir are drugs to treat COVID-19. This study aims to find an optimum and validated method for simultaneous analysis of favipiravir and remdesivir in Volumetric Absorptive Microsampling (VAMS) by Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrophotometry. The use of VAMS can be an advantage because the volume of blood is small and the sample preparation process is simple. Sample preparation was done by precipitation of protein using 500 μL of methanol. Analysis was carried out by ultra high-performance liquid chromatography-tandem mass spectrophotometry with ESI+ and MRM with m/z 157.9 > 112.92 for favipiravir, 603.09 > 200.005 for remdesivir, and at m/z 225.968 > 151.991 for acyclovir as the internal standard. The separation was carried out using an Acquity UPLC BEH C₁₈ column (100 × 2.1 mm; 1.7 m), 0.2% formic acid-acetonitrile (50:50), flow rate was 0.15 mL/min, and column temperature was 50°C. The analytical method has been validated with the requirements issued by the Food and Drug Administration (2018) and European Medicine Agency (2011). The calibration range of favipiravir is 0.5-160 μg/mL and 0.002-8 μg/mL for remdesivir.