Applications of metal organic frameworks in dispersive micro solid phase extraction (D-μ-SPE).

Metal-organic frameworks (MOFs) are a fascinating family of crystalline porous materials made up of metal clusters and organic linkers. In comparison with other porous materials, MOFs have unique characteristics including high surface area, homogeneous open cavities, and permanent high porosity with variable shapes and sizes. For these reasons, MOFs have recently been explored as sorbents in sample preparation by solid-phase extraction (SPE).

Homogeneous liquid-liquid microextraction coupled with HPLC/DAD for determination of nirmatrelvir and ritonavir as COVID-19 combination therapy in human plasma.

The study reports the development of a high-performance liquid chromatography/diode array detection method to measure the levels of nirmatrelvir and ritonavir in human plasma. These two antiviral medications are used for the treatment of COVID-19 and are marketed as Paxlovid. The method employed sugaring-out induced homogeneous liquid-liquid microextraction to improve sensitivity.

Analytical Methods for the Determination of Quercetin and Quercetin Glycosides in Pharmaceuticals and Biological Samples.

Flavonoids are plant-derived compounds that have several health benefits, including antioxidative, anti-inflammatory, anti-mutagenic, and anti-carcinogenic effects. Quercetin is a flavonoid that is widely present in various fruits, vegetables, and drinks. Accurate determination of quercetin in different samples is of great importance for its potential health benefits.

A hybrid microcrystalline cellulose/metal-organic framework for dispersive solid phase microextraction of selected pharmaceuticals: A proof-of-concept.

Solid phase microextraction (SPME) is considered simple, ecofriendly, sustainable, cost-effective and timesaving sample preparation mode in comparison with other sample preparation procedures. The researchers always try to develop new sorbents with higher surface area in comparison with other conventional sorbents aiming to enhance the extraction efficiency. In this work for the first time, a comparative study was performed between Ca-BTC MOF (1,3,5-benzenetricarboxylic acid, BTC; metal-organic framework, MOF) and a hybrid Ca-BTC-MCC MOF (microcrystalline cellulose, MCC) by using as model compounds seven drugs with different physicochemical properties.

The anti-COVID-19 drug Favipiravir: Degradation, Method development, Validation, NMR/LC-MS characterization, and safety evaluation.

It is critical to characterize the degradation products of therapeutic drugs to determine their safety as these degradation products may possess fatal effects on the human physiological system. Favipiravir (FVP), a novel anti-Covid-19 drug, that is recently used all over the world with a great impact on humanity was our target to explore more about its toxicity, the margins of its safety, and its degradants in different degradation conditions. The goal of this study is to identify, characterize, and confirm the structures of FVP oxidative and alkaline breakdown products, as well as to assess their safety utilizing SRB cytotoxicity assay on normal human skin fibroblasts (NHSF) cell lines.

Lipid polymer hybrid nanocarriers as a combinatory platform for different anti-SARS-CoV-2 drugs supported by computational studies.

The COVID-19 pandemic caused by SARS-CoV-2 has demonstrated the potential of emergent pathogens to severely damage public health and global economies. As a consequence of the pandemic, millions of people have been forced into self-isolation, which has negatively affected the global economy. More efforts are needed to find new innovative approaches that could fundamentally change our understanding and management of this disaster.

A gadolinium-based magnetic ionic liquid for supramolecular dispersive liquid-liquid microextraction followed by HPLC/UV for the determination of favipiravir in human plasma.

Favipiravir is a potential antiviral medication that has been recently licensed for Covid-19 treatment. In this work, a gadolinium-based magnetic ionic liquid was prepared and used as an extractant in dispersive liquid-liquid microextraction (DLLME) of favipiravir in human plasma. The high enriching ability of DLLME allowed the determination of favipiravir in real samples using HPLC/UV with sufficient sensitivity.

Determination of favipiravir in human plasma using homogeneous liquid-liquid microextraction followed by HPLC/UV.

Favipiravir is an antiviral drug that was recently approved for the management of COVID-19 infection. This work aimed to develop a new method, using sugaring-out induced homogeneous liquid-liquid microextraction followed by HPLC/UV for the determination of favipiravir in human plasma. The optimum extraction conditions were attained using 500 μl of tetrahydrofuran as an extractant and 1400 mg of fructose as a phase-separating agent.

Development and validation of a simple and sensitive LC-MS/MS method for the quantification of cefazolin in human plasma and its application to a clinical pharmacokinetic study.

Cefazolin is widely used during surgery to prevent surgical site infections (SSIs). Although cefazolin redosing is often needed due to its short half-life, the appropriate redosing schedule remains controversial and there is limited information on cefazolin disposition following repeated doses during surgery. In parallel with an ongoing cefazolin redosing clinical study, we have developed and fully validated a simple and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of cefazolin in human plasma.

Menthol-assisted homogenous liquid-liquid microextraction for HPLC/UV determination of favipiravir as an antiviral for COVID-19 in human plasma.

Favipiravir is a promising antiviral agent that has been recently approved for treatment of COVID-19 infection. In this study, a menthol-assisted homogenous liquid-liquid microextraction method has been developed for favipiravir determination in human plasma using HPLC/UV. The different factors that could affect the extraction efficiency were studied, including extractant type, extractant volume, menthol amount and vortex time.

Structure- and Ligand-Based Studies towards the Repurposing of Marine Bioactive Compounds to Target SARS-CoV-2.

This work was a structured virtual screening for marine bioactive compounds with reported antiviral activities which were subjected to structure-based studies against SARS-CoV-2 co-crystallized proteins. The molecular docking of marine bioactive compounds against the main protease (M, PDB ID: 6lu7 and 6y2f), the spike glycoprotein (PDB ID: 6vsb), and the RNA polymerase (PDB ID: 6m71) of SARS-CoV-2 was performed. Ligand-based approach with the inclusion of rapid overlay chemical structures (ROCS) was also addressed in order to examine the probability of these marine compounds sharing relevance and druggability with the reported drugs.

Enantioselective Separation of Chiral N1-Substituted-1-pyrazoles: Greenness Profile Assessment and Chiral Recognition Analysis.

Two commercialized polysaccharide-based chiral stationary phases, Lux cellulose-2 and Lux amylose-2, were examined for their chiral recognition ability on a set of 18 biologically active racemic 4,5-dihydro-1-pyrazole derivatives by applying normal and polar organic elution modes. The results showed that all compounds were baseline-resolved with at least one of the used elution modes. The cellulose-based column was superior using polar organic mobile-phase compositions with analysis times close to 5 min and resolutions up to 18, while the enantiomer-resolving ability of amylose-based columns was greater using the normal elution mode with analysis times close to 30 min and resolutions up to 30.

Homogeneous liquid-liquid extraction as an alternative sample preparation technique for biomedical analysis.

Liquid-liquid extraction is a widely used technique of sample preparation in biomedical analysis. In spite of the high pre-concentration capacities of liquid-liquid extraction, it suffers from a number of limitations including time and effort consumption, large organic solvent utilization, and poor performance in highly polar analytes. Homogeneous liquid-liquid extraction is an alternative sample preparation technique that overcomes some drawbacks of conventional liquid-liquid extraction, and allows employing greener organic solvents in sample treatment.

Sugaring-out induced homogeneous liquid-liquid microextraction as an alternative mode for biological sample preparation: A comparative study.

Miniaturization of liquid-liquid extraction is a growing field of sample preparation to reduce solvent consumption, protect the environment, and preserve operators' health. In this work, four different modes of liquid-liquid microextraction have been compared including dispersive liquid-liquid microextraction, binary and ternary salting-out, and sugaring-out induced liquid-liquid microextraction. The extraction efficiency was evaluated by the enrichment factors of 14 different drugs from three pharmacological classes.

Salting-out induced liquid-liquid microextraction for alogliptin benzoate determination in human plasma by HPLC/UV.

Salting-out induced liquid-liquid microextraction method has been developed for plasma sample treatment before determination of alogliptin by high performance liquid chromatography with UV detection. Several parameters were optimized to achieve maximum enrichment, including type of extractant, volume of extractant, type of anion, type of cation, salt amount and pH. The optimum conditions were attained using 500 µL of acetonitrile, added to 1 mL of aqueous sample containing 250 mg of sodium chloride at pH 12.

Identification, isolation, structural characterization, toxicity prediction and cytotoxicity assay of simeprevir acidic and oxidative degradation products.

Simeprevir is a new direct-acting antiviral drug used for the treatment of chronic hepatitis C. In this work, a simple, fast and economical chromatographic method was developed for the determination of simeprevir in the presence of its acidic and oxidative degradation products. The stress studies performed herein showed that simeprevir degraded under acidic and oxidative conditions but was stable under thermal and alkaline conditions.

Determination of flibanserin in the presence of confirmed degradation products by a third derivative emission spectrofluorometric method: Application to pharmaceutical formulation.

Flibanserin is a new drug used for the treatment of hypoactive sexual desire disorder. This work is considered the first study concerning the fluorimetric behaviour of flibanserin and its new florescent degradation products. A fast, cost-effective, stability-indicating spectrofluorometric method was developed and validated for the determination of flibanserin in the presence of oxidative degradation products.

LC-MS determination of fentanyl in human serum and application to a fentanyl transdermal delivery pharmacokinetic study.

Aim: Fentanyl is an opioid agonist used for acute and chronic pain management. In this report, a highly sensitive and simple LC-MS/MS method using Hydrophilic Interaction Chromatography (HILIC) column was validated and used for fentanyl quantification in human serum.

Results: The isocratic mobile phase was composed of acetonitrile: 10 mM ammonium formate buffer (pH = 3.

Precise simultaneous quantification of methadone and cocaine in rat serum and brain tissue samples following their successive i.p. administration.

A sensitive high-performance liquid chromatography (HPLC) assay with dual UV detection has been developed and validated for the simultaneous quantification of methadone and cocaine in rat serum and brain tissue samples. Liquid-liquid extraction using hexanes was applied for samples extraction with Levo-Tetrahydropalmatine (L-THP) as the internal standard. Chromatographic separation of the analytes was achieved on a reversed-phase Waters Symmetry C column (150mm×4.

Development and validation of a high performance liquid chromatography quantification method of levo-tetrahydropalmatine and its metabolites in plasma and brain tissues: application to a pharmacokinetic study.

Levo-tetrahydropalmatine (l-THP) is an alkaloid isolated from Chinese medicinal herbs of the Corydalis and Stephania genera. It has been used in China for more than 40 years mainly as an analgesic with sedative/hypnotic effects. Despite its extensive use, its metabolism has not been quantitatively studied, nor there a sensitive reliable bioanalytical method for its quantification simultaneously with its metabolites.

A fully validated LC-MS/MS method for simultaneous determination of nicotine and its metabolite cotinine in human serum and its application to a pharmacokinetic study after using nicotine transdermal delivery systems with standard heat application in adult smokers.

A sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of nicotine and its main metabolite cotinine in human serum samples. Liquid-liquid extraction using ethyl acetate was employed for serum sample extractions. Chromatographic separation was achieved on Phenomenex Luna(®) HILIC column (150 mm x 3.

Norelgestromin/ethinyl estradiol intravenous infusion formulation optimization, stability and compatibility testing: A case study to overcome polysorbate 80 interference in chromatographic analysis.

Norelgestromin/ethinyl estradiol is a progestin/estrogen combination hormonal contraceptive indicated for the prevention of pregnancy in women. The very poor solubility and wettability of these drugs, along with their high potency (adsorption issues), give rise to difficulties in designing intravenous (IV) formulations to assess absolute bioavailability of products containing both drugs. The purpose of this study was to develop an IV formulation, evaluate its stability under different conditions and evaluate its compatibility with IV sets for potential use in absolute bioavailability studies in humans.