Sensitive and selective bioscreening of the most commonly used coronavirus disease drug, Favipiravir, and its co-administered therapeutic, Meropenem, in human plasma.

Favipiravir and Meropenem have been concurrently used as directly acting antiviral and antibiotic agents for the treatment of coronavirus disease in human plasma. Accurate and specific reversed phase ultra-performance liquid chromatographic and high-performance thin-layer chromatographic methods were developed and validated for the first time analysis of this combination in spiked human plasma using Cefepime as an internal standard. In the developed ultra-high-performance liquid chromatography method, separation was performed on a BEH C18 column with a mixture of ACN and 0.05 M potassium dihydrogen orthophosphate (pH = 3) in a ratio of 10:90 (v/v) as an eluate. Scanning of the separated peaks was at 298 nm. The developed method showed high sensitivity, and the drugs showed linearity in the range of 5-70 µg/ml for Favipiravir and 2-50 µg/ml for Meropenem. The proposed high-performance thin-layer chromatographic method included the separation using a mixture of ethyl acetate:methanol:deionized water:formic acid (5:4:1.5:0.3, by volume), then spots detection at 300 nm. Methods were investigated for greenness using the eco-scale and national environmental method index tools and were validated according to food and drug administration guidelines. Methods can be applied for bio-analysis and therapeutic drug monitoring studies.

Rapid and ecofriendly UPLC quantification of Remdesivir, Favipiravir and Dexamethasone for accurate therapeutic drug monitoring in Covid-19 Patient's plasma.

Innovative therapeutic protocols to the rapidly spreading coronavirus disease (COVID19) epidemic is highly required all across the world. As demonstrated by clinical studies, Favipiravir (FVP) and Remdesivir (REM) are new antiviral medicines that are effective against COVID-19. REM is the first FDA approved antiviral medicine against COVID-19. In addition to antivirals, corticosteroids such as dexamethasone (DEX), and anticoagulants such as apixaban (PX) are used in multidrug combinations protocols. This work develops and validates simple and selective screening of the four medicines of COVID -19 therapeutic protocol. FVP, REM, DEX, and PX as internal standard in human plasma using UPLC method by C18 column and methanol, acetonitrile, and water acidified by orthophosphate (pH = 4) in a ratio of (15: 35: 50, by volume) as an eluate flowing at 0.3 mL/min. The eluent was detected at 240 nm. The method was linear over (0.1-10 µg/mL) for each of FVP, REM, and DEX. The validation of the UPLC method was assessed in accordance with FDA guidelines. The method can detect as low as down to 0.1 µg/mL for all. The recoveries of the drugs in spiked human plasma ranged from 97.67 to 102.98 percent. Method accuracy and precision were assessed and the drugs showed good stability. The method was proven to be green to the environment after greenness checking by greenness profile and Eco-Scale tool.

Baclofen impurities: Facile synthesis and novel environmentally benign chromatographic method for their simultaneous determination in baclofen.

An efficient, economic and high yielding method was described for the synthesis of baclofen (BAC) pharmacopoeial impurities (impurity A and impurity B) which can be used for gram-scale synthesis. Furthermore, a novel ecofriendly thin-layer chromatographic TLC-densitometric method was established and validated for the determination of BAC and its synthesized impurities. The developed TLC-densitometric method is based on the chromatographic separation using TLC plates (60 F254 ) using a green mobile phase of ethyl acetate-methanol-ammonia solution, 33% (8:2:0.1, by volume) with UV scanning at 220 nm. The proposed method was validated with respect to International Conference on Harmonization guidelines. The validated method was successfully applied for determination of BAC in pure form and in its commercial dosage form. Additionally, the greenness profile of the developed method was evaluated and compared with those of the reported chromatographic methods. The developed method was found to be superior to the published methods, being environmentally benign.

Efficient UPLC and CE methods for the simultaneous determination of azelastine hydrochloride and its genotoxic impurity.

A novel stability-indicating UPLC and CE method was established and validated for the determination of azelastine hydrochloride (AZL) and its genotoxic impurity, benzohydrazide, in the presence of benzalkonium chloride. The developed UPLC method was based on chromatographic separation using a C18 column as a stationary phase and acetonitrile-(0.1% w/v) aqueous sodium lauryl sulfate (55:45, v/v, pH 5 with phosphoric acid) as a mobile phase with a flow rate of 1.2 mL/min and UV detection at 215 nm. The chromatographic run time was ~2 min. The developed CE method depended on using a stationary phase of Standard Bare Fused Silica Capillaries (75 µm i.d. × 59 cm and 50 cm detection length) and the applied voltage was 30 kV using 40 mm phosphate buffer (pH 2 with aqueous H3 PO4 ); the detection wavelength was 225 nm. The analysis time was about 6 min. The suggested methods were successfully applied for the analysis of AZL in a pharmaceutical preparation. The validity of the developed methods was assessed by applying the standard addition technique and no interference from excipients was observed. The results obtained by the proposed methods were statistically analyzed and compared with the manufacturer's method and no significant difference was found between the compared methods.

Different Spectrophotometric and Chromatographic Methods for Determination of Mepivacaine and Its Toxic Impurity.

Stability-indicating spectrophotometric, TLC-densitometric, and ultra-performance LC (UPLC) methods were developed for the determination of mepivacaine HCl (MEP) in the presence of its toxic impurity, 2,6-dimethylanaline (DMA). Different spectrophotometric methods were developed for the determination of MEP and DMA. In a dual-wavelength method combined with direct spectrophotometric measurement, the absorbance difference between 221.4 and 240 nm was used for MEP measurements, whereas the absorbance at 283 nm was used for measuring DMA in the binary mixture. In the second-derivative method, amplitudes at 272.2 and 232.6 nm were recorded and used for the determination of MEP and DMA, respectively. The developed TLC-densitometric method depended on chromatographic separation using silica gel 60 F254 TLC plates as a stationary phase and methanol-water-acetic acid (9 + 1 + 0.1, v/v/v) as a developing system, with UV scanning at 230 nm. The developed UPLC method depended on separation using a C18 column (250 × 4.6 mm id, 5 µm particle size) as a stationary phase and acetonitrile-water (40 + 60, v/v; pH 4 with phosphoric acid) as a mobile phase at a flow rate of 0.4 mL/min, with UV detection at 215 nm. The chromatographic run time was approximately 1 min. The proposed methods were validated with respect to International Conference on Harmonization guidelines regarding precision, accuracy, ruggedness, robustness, and specificity.