UPLC-HR-MS/MS-based determination study on the metabolism of four synthetic cannabinoids ADB-FUBICA, AB-FUBICA, AB-BICA and ADB-BICA, by human liver microsomes

Since 2012, several cannabimimetic indazole and indole derivatives with valine amino acid amide residue have emerged in the illicit drug market, and gradually replaced the old generations of synthetic cannabinoids (SCs) with naphthyl or adamantine groups. Among them, ADB-FUBICA, AB-FUBICA, AB-BICA and ADB-BICA were detected in China recently, but unfortunately no information about their in vitro human metabolism is available for now. Therefore, biomonitoring studies to screen their consumption lack any information about the potential biomarkers (e.g.metabolites) to target. To bridge this gap, we investigated their phase I metabolism by incubating with human liver microsomes, and the metabolites were identified by Ultra Performance liquid chromatography-high resolution-tandem mass spectrometry (UPLC-HR-MS/MS).
Metabolites generated by N-dealkylation and hydroxylation on the 1-amino-alkyl moiety were found to be predominant for all these four substances, and others which underwent hydroxylation, amide hydrolysis and dehydrogenation were also observed in our investigation. Based on our research, we recommend that the N-dealkylation and hydroxylation metabolites are suitable and appropriate analytical markers for monitoring their intake.

Abstract

Since 2012, several cannabimimetic indazole and indole derivatives with valine amino acid amide residue have emerged in the illicit drug market, and gradually replaced the old generations of synthetic cannabinoids (SCs) with naphthyl or adamantine groups. Among them, ADB-FUBICA, AB-FUBICA, AB-BICA and ADB-BICA were detected in China recently, but unfortunately no information about their in vitro human metabolism is available for now. Therefore, biomonitoring studies to screen their consumption lack any information about the potential biomarkers (e.g.metabolites) to target. To bridge this gap, we investigated their phase I metabolism by incubating with human liver microsomes, and the metabolites were identified by Ultra Performance liquid chromatography-high resolution-tandem mass spectrometry (UPLC-HR-MS/MS).

Metabolites generated by N-dealkylation and hydroxylation on the 1-amino-alkyl moiety were found to be predominant for all these four substances, and others which underwent hydroxylation, amide hydrolysis and dehydrogenation were also observed in our investigation. Based on our research, we recommend that the N-dealkylation and hydroxylation metabolites are suitable and appropriate analytical markers for monitoring their intake.

A review of bioanalytical quantitative methods for selected sphingosine 1-phosphate (S1P1) receptor modulators

Sphingosine 1-phosphate (S1P1) modulators provide an emerging therapeutic approach for various autoimmune disorders such as multiple sclerosis and psoriasis. Fingolimod is the first approved orally active, selective and potent drug of this class. Other drugs belonging to this class include siponimod, ponesimod, ceralifimod, amiselimod, CS-0777 and GSK2018682. However, due to the high protein binding, polarity and zwitter-ionic nature of the phosphate metabolite of parent drugs, it becomes challenging to optimize the extraction method for this class of compounds. Although, there are individual published bioanalytical methods for the analysis of selected S1P1 modulators to support preclinical and clinical drug development, no extensive review compiling all the bioanalytical methods for the important drugs in the class is available. Thus, we attempted to prepare a comprehensive review on various bioanalytical methods for selected S1P1 modulators which will provide all the relevant bioanalytical information as required by bioanalytical researchers. This review focuses on the various liquid chromatography with tandem mass spectrometry (LC-MS/MS) methods that have been used to quantify S1P1 modulators in various biological matrices. Extraction methods included liquid-liquid extraction, solid-phase extraction and one step protein precipitation for extracting the analytes. This review captures key information regarding sample processing options and chromatographic/detection conditions.

Abstract

Sphingosine 1-phosphate (S1P1) modulators provide an emerging therapeutic approach for various autoimmune disorders such as multiple sclerosis and psoriasis. Fingolimod is the first approved orally active, selective and potent drug of this class. Other drugs belonging to this class include siponimod, ponesimod, ceralifimod, amiselimod, CS-0777 and GSK2018682. However, due to the high protein binding, polarity and zwitter-ionic nature of the phosphate metabolite of parent drugs, it becomes challenging to optimize the extraction method for this class of compounds. Although, there are individual published bioanalytical methods for the analysis of selected S1P1 modulators to support preclinical and clinical drug development, no extensive review compiling all the bioanalytical methods for the important drugs in the class is available. Thus, we attempted to prepare a comprehensive review on various bioanalytical methods for selected S1P1 modulators which will provide all the relevant bioanalytical information as required by bioanalytical researchers. This review focuses on the various liquid chromatography with tandem mass spectrometry (LC-MS/MS) methods that have been used to quantify S1P1 modulators in various biological matrices. Extraction methods included liquid-liquid extraction, solid-phase extraction and one step protein precipitation for extracting the analytes. This review captures key information regarding sample processing options and chromatographic/detection conditions.

Anti-inflammatory activities and glycerophospholipids metabolism in KLA-stimulated RAW 264.7 macrophage cells by diarylheptanoids from the rhizomes of Alpinia officinarum

Alpinia officinarum is used for its anti-inflammatory activity historically in China. Diarylheptanoids isolated from A. officinarum play important biological roles in the prevention and treatment of inflammatory disorders. Seven diarylheptanoids (1–7) were isolated from A. officinarum. The cell viabilities and anti-inflammatory activities of diarylheptanoids were evaluated by MTT assay and tumor necrosis factor-α production in Kdo2-lipid A-stimulated RAW 264.7 cells in vitro. The relationships between their anti-inflammatories and structure-activities are discussed. The results indicated that compounds 1 and 3–7 had significant anti-inflammatory activities. The relationships between inflammation and phospholipids metabolism were elucidated by multivariate data analysis. Twenty-two potential biomarkers were identified in inflammatory group vs. blank group, and 11 potential biomarkers were identified for inflammatory group vs. drug-treatment groups. Ten common phospholipids were characterized. On the basis of a previous study in our laboratory, we found that phosphatidylethanolamine (18:0/18:1) might be the important glycerophospholipid biomarker in inflammation. In this study, we firstly combined anti-inflammatory activities and glycerophospholipids changes of traditional Chinese medicine. This work suggests that the anti-inflammatory activities of diarylheptanoids might be significantly related to glycerophospholipids and could provide a useful database for investigating the anti-inflammatory effects of traditional Chinese medicine.

Abstract

Alpinia officinarum is used for its anti-inflammatory activity historically in China. Diarylheptanoids isolated from A. officinarum play important biological roles in the prevention and treatment of inflammatory disorders. Seven diarylheptanoids (1–7) were isolated from A. officinarum. The cell viabilities and anti-inflammatory activities of diarylheptanoids were evaluated by MTT assay and tumor necrosis factor-α production in Kdo2-lipid A-stimulated RAW 264.7 cells in vitro. The relationships between their anti-inflammatories and structure-activities are discussed. The results indicated that compounds 1 and 3–7 had significant anti-inflammatory activities. The relationships between inflammation and phospholipids metabolism were elucidated by multivariate data analysis. Twenty-two potential biomarkers were identified in inflammatory group vs. blank group, and 11 potential biomarkers were identified for inflammatory group vs. drug-treatment groups. Ten common phospholipids were characterized. On the basis of a previous study in our laboratory, we found that phosphatidylethanolamine (18:0/18:1) might be the important glycerophospholipid biomarker in inflammation. In this study, we firstly combined anti-inflammatory activities and glycerophospholipids changes of traditional Chinese medicine. This work suggests that the anti-inflammatory activities of diarylheptanoids might be significantly related to glycerophospholipids and could provide a useful database for investigating the anti-inflammatory effects of traditional Chinese medicine.

A rapid and simple HPTLC assay for therapeutic drug monitoring of capecitabine in colorectal cancer patients

Capecitabine is a prodrug of 5-flurouracil, employed as a broad spectrum chemotherapeutic agent. It is also used as monotherapy or a combination chemotherapy agent for the treatment of colorectal cancer. Capecitabine is administered in combination with oxaliplatin and hence it is essential to determine that co-administration does not affect its metabolism. To determine the plasma concentration of capecitabine a simple HPTLC method was developed and validated. Blood samples from 12 patients with colorectal cancer were collected and analyzed by the HPTLC method with a reference internal standard. Out of these 12 patients, six were treated with capecitabine monotherapy and another six were treated with capecitabine + oxaliplatin combination therapy. The results of analysis indicated that there was no significant drug–drug interaction and the co-administration of oxaliplatin did not affect the metabolism of capecitabine. This method is sensitive, robust and specific and allows analysis of multiple samples simultaneously, making it suitable for therapeutic drug monitoring of capecitabine.

Abstract

Capecitabine is a prodrug of 5-flurouracil, employed as a broad spectrum chemotherapeutic agent. It is also used as monotherapy or a combination chemotherapy agent for the treatment of colorectal cancer. Capecitabine is administered in combination with oxaliplatin and hence it is essential to determine that co-administration does not affect its metabolism. To determine the plasma concentration of capecitabine a simple HPTLC method was developed and validated. Blood samples from 12 patients with colorectal cancer were collected and analyzed by the HPTLC method with a reference internal standard. Out of these 12 patients, six were treated with capecitabine monotherapy and another six were treated with capecitabine + oxaliplatin combination therapy. The results of analysis indicated that there was no significant drug–drug interaction and the co-administration of oxaliplatin did not affect the metabolism of capecitabine. This method is sensitive, robust and specific and allows analysis of multiple samples simultaneously, making it suitable for therapeutic drug monitoring of capecitabine.

Simple determination of betaine, L-carnitine and choline in human urine using self-packed column and column-switching ion chromatography with non-suppressed conductivity detection

A sequential on-line extraction, clean-up and separation system for the determination of betaine, L-carnitine and choline in human urine using column-switching ion chromatography with non-suppressed conductivity detection was developed in this work. Self-packed pretreatment column (50 mm×4.6 mm, i.d.) was used for the extraction and clean-up of betaine, L-carnitine and choline. The separation was achieved using self-packed cationic exchange column (150 mm×4.6 mm, i.d.), followed by non-suppressed conductivity detection. Under optimized experimental conditions, the developed method presented good analytical performance, with excellent linearity in ranged of 0.60-100 μg mL-1 for betaine, 0.75-100 μg mL-1 for L-carnitine and 0.50-100 μg mL-1 for choline, with all correlation coefficient (R2) above 0.99 in urine. The limits of detection (LOD) were of 0.15 μg mL-1 for betaine and 0.20 μg mL-1 for L-carnitine and 0.09 μg mL-1 for choline. The intra- and inter-day accuracy and precision for all quality controls were within ±10.32% and ±9.05%, respectively. Satisfactory recovery was observed between 92.8% and 102.0%. The validated method was successfully applied to the detection of urinary samples from 10 healthy people. The values detected in human urine using the proposed method had a good agreement with the measurement reported previously.

Abstract

A sequential on-line extraction, clean-up and separation system for the determination of betaine, L-carnitine and choline in human urine using column-switching ion chromatography with non-suppressed conductivity detection was developed in this work. Self-packed pretreatment column (50 mm×4.6 mm, i.d.) was used for the extraction and clean-up of betaine, L-carnitine and choline. The separation was achieved using self-packed cationic exchange column (150 mm×4.6 mm, i.d.), followed by non-suppressed conductivity detection. Under optimized experimental conditions, the developed method presented good analytical performance, with excellent linearity in ranged of 0.60-100 μg mL-1 for betaine, 0.75-100 μg mL-1 for L-carnitine and 0.50-100 μg mL-1 for choline, with all correlation coefficient (R2) above 0.99 in urine. The limits of detection (LOD) were of 0.15 μg mL-1 for betaine and 0.20 μg mL-1 for L-carnitine and 0.09 μg mL-1 for choline. The intra- and inter-day accuracy and precision for all quality controls were within ±10.32% and ±9.05%, respectively. Satisfactory recovery was observed between 92.8% and 102.0%. The validated method was successfully applied to the detection of urinary samples from 10 healthy people. The values detected in human urine using the proposed method had a good agreement with the measurement reported previously.

Bioassay, determination and separation of enantiomers of atenolol by direct and indirect approaches using liquid chromatography: A review

Atenolol, a β-adrenergic receptor antagonist, is a chiral compound used for the treatment of cardiovascular diseases and to treat hypertension, coronary heart disease, arrhythmias, sinus tachycardia and myocardial infarction, where it acts preferentially upon the β-adrenergic receptors in the heart. It is marketed as a racemate, but only the (S)-enantiomer of (RS)-atenolol is responsible for the β-adrenoceptor blocking activity. Different chromatographic methods have been applied for the separation and determination of enantiomers. In this article a review is presented on liquid chromatographic methods for enantioseparation of (RS)-atenolol by both direct and indirect approaches involving practical applications of several chiral stationary phases, chiral derivatization reagents and ligand exchange and impregnation methods. These include methods using both HPLC and TLC for separation, determination and bioassay of enantiomers of atenolol. In addition, some aspects of enantioseparation under achiral phases of liquid chromatography have been briefly mentioned as applicable to (RS)-atenolol. This review provides current available enantioseparation choices not only for (RS)-atenolol but also for other applicable racemic drugs.

Abstract

Atenolol, a β-adrenergic receptor antagonist, is a chiral compound used for the treatment of cardiovascular diseases and to treat hypertension, coronary heart disease, arrhythmias, sinus tachycardia and myocardial infarction, where it acts preferentially upon the β-adrenergic receptors in the heart. It is marketed as a racemate, but only the (S)-enantiomer of (RS)-atenolol is responsible for the β-adrenoceptor blocking activity. Different chromatographic methods have been applied for the separation and determination of enantiomers. In this article a review is presented on liquid chromatographic methods for enantioseparation of (RS)-atenolol by both direct and indirect approaches involving practical applications of several chiral stationary phases, chiral derivatization reagents and ligand exchange and impregnation methods. These include methods using both HPLC and TLC for separation, determination and bioassay of enantiomers of atenolol. In addition, some aspects of enantioseparation under achiral phases of liquid chromatography have been briefly mentioned as applicable to (RS)-atenolol. This review provides current available enantioseparation choices not only for (RS)-atenolol but also for other applicable racemic drugs.

Pharmacokinetics and metabolism of olerciamide A from Portulaca oleracea L. in rats by UHPLC-UV and UHPLC-ESI-Q-TOF/MS

The aim of this study was to elucidate the pharmacokinetics of olerciamide A in rats after oral and intravenous administration of Portulaca oleracea L. extract by a simple and rapid ultra high-performance liquid chromatography method with bergapten as internal standard. The pharmacokinetic results indicated that olerciamide A was rapidly distributed with a time to peak concentration of 30 min after oral administration and presented a low oral absolute bioavailability of 4.57%. The metabolism of olerciamide A in rats was also investigated using ultra-high-performance liquid chromatography electrospray coupled with quadrupole–time of flight mass spectrometry to elucidate the reason for the low absolute bioavailability of olerciamide A and seven metabolites of oleraciamide A were found in rat plasma and urine.

Abstract

The aim of this study was to elucidate the pharmacokinetics of olerciamide A in rats after oral and intravenous administration of Portulaca oleracea L. extract by a simple and rapid ultra high-performance liquid chromatography method with bergapten as internal standard. The pharmacokinetic results indicated that olerciamide A was rapidly distributed with a time to peak concentration of 30 min after oral administration and presented a low oral absolute bioavailability of 4.57%. The metabolism of olerciamide A in rats was also investigated using ultra-high-performance liquid chromatography electrospray coupled with quadrupole–time of flight mass spectrometry to elucidate the reason for the low absolute bioavailability of olerciamide A and seven metabolites of oleraciamide A were found in rat plasma and urine.

Simultaneous determination of glaucocalyxin A and glaucocalyxin B in rat plasma by LC-MS/MS and its application to a pharmacokinetic study after oral administration of Rabdosia japonica extract

A specific and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the analysis of glaucocalyxin A and glaucocalyxin B in rat plasma using praeruptorin A as an internal standard. Separation was performed on a Hypurity C18 column (2.1 × 50 mm, 5 μm) with isocratic elution using 0.2% formic acid in water–acetonitrile (20:80, v/v). Mass spectrometric detection was conducted using selected reaction monitoring via an electrospray ionization source. Both analytes exhibited good linearity within their concentration ranges (r2 > 0.9932). The lower limit of quantitation of glaucocalyxin A and glaucocalyxin B was 1.10 ng/mL. Intra- and inter-day precision exhibited an RSD within 14.5%, and the accuracy (RE) ranged from –12.1 to 15.0% at the lower limit of quantitation and three quality control levels. The developed assay was successfully applied to a pharmacokinetic study of glaucocalyxin A and glaucocalyxin B in rats after oral administration of Rabdosia japonica extract.

Abstract

A specific and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the analysis of glaucocalyxin A and glaucocalyxin B in rat plasma using praeruptorin A as an internal standard. Separation was performed on a Hypurity C18 column (2.1 × 50 mm, 5 μm) with isocratic elution using 0.2% formic acid in water–acetonitrile (20:80, v/v). Mass spectrometric detection was conducted using selected reaction monitoring via an electrospray ionization source. Both analytes exhibited good linearity within their concentration ranges (r2 > 0.9932). The lower limit of quantitation of glaucocalyxin A and glaucocalyxin B was 1.10 ng/mL. Intra- and inter-day precision exhibited an RSD within 14.5%, and the accuracy (RE) ranged from –12.1 to 15.0% at the lower limit of quantitation and three quality control levels. The developed assay was successfully applied to a pharmacokinetic study of glaucocalyxin A and glaucocalyxin B in rats after oral administration of Rabdosia japonica extract.

Chromatographic approaches for the characterization and quality control of therapeutic oligonucleotide impurities

Phosphorothioate (PS) oligonucleotides are a rapidly rising class of drugs with significant therapeutic applications. However, owing to their complex structure and multistep synthesis and purification processes, generation of low-level impurities and degradation products are common. Therefore, they require significant investment in quality control and impurity identification. This requires the development of advanced methods for analysis, characterization and quantitation. In addition, the presence of the PS linkage leads to the formation of chiral centers which can affect their biological properties and therapeutic efficiency. In this review, the different types of oligonucleotide impurities and degradation products, with an emphasis on their origin, mechanism of formation and methods to reduce, prevent or even eliminate their production, will be extensively discussed. This review will focus mainly on the application of chromatographic techniques to determine these impurities but will also discuss other approaches such as mass spectrometry, capillary electrophoresis and nuclear magnetic resonance spectroscopy. Finally, the chirality and formation of diastereomer mixtures of PS oligonucleotides will be covered as well as approaches used for their characterization and the application for the development of stereochemically-controlled PS oligonucleotides.

Abstract

Phosphorothioate (PS) oligonucleotides are a rapidly rising class of drugs with significant therapeutic applications. However, owing to their complex structure and multistep synthesis and purification processes, generation of low-level impurities and degradation products are common. Therefore, they require significant investment in quality control and impurity identification. This requires the development of advanced methods for analysis, characterization and quantitation. In addition, the presence of the PS linkage leads to the formation of chiral centers which can affect their biological properties and therapeutic efficiency. In this review, the different types of oligonucleotide impurities and degradation products, with an emphasis on their origin, mechanism of formation and methods to reduce, prevent or even eliminate their production, will be extensively discussed. This review will focus mainly on the application of chromatographic techniques to determine these impurities but will also discuss other approaches such as mass spectrometry, capillary electrophoresis and nuclear magnetic resonance spectroscopy. Finally, the chirality and formation of diastereomer mixtures of PS oligonucleotides will be covered as well as approaches used for their characterization and the application for the development of stereochemically-controlled PS oligonucleotides.

Exploring the mechanism of Jieduquyuziyin Prescription on Systemic Lupus Erythematosus by GC-MS-based Urine Metabolomics

A urine metabolomics method based on gas chromatography mass spectrometry (GC-MS) was developed in order to investigate the metabolites characters of systemic lupus erythematosus (SLE) and therapeutic effects of jieduquyuziyin prescription (JP). The urinary metabolic profiles in urine specimens of the SLE model mice (MRL/lpr) group, prednisone acetate (PA)-treated SLE mice group, JP-treated SLE mice group, and control group (C57BL/6 J) after the administration were analyzed by GC-MS. These metabolic profiles were then processed by multivariate analysis, in particular Mass Profiler Professional (MPP), SIMCA-P and partial least-squares discriminant analysis (PLS-DA). According to the PLS-DA results, the SLE model group and the control group were obviously separated, indicating that the incidence of SLE had a greater impact on the metabolic network, and the SLE model group had significant difference compared with the control group in urine metabolites. 11 differential metabolites were identified to be related to SLE. And the results of differential metabolite identification showed that the metabolites were mainly related to energy metabolism and amino acid metabolism pathway. These results can provide an experimental basis for further exploring the mechanism of traditional Chinese medicine (TCM) in the treatment of SLE.

Abstract

A urine metabolomics method based on gas chromatography mass spectrometry (GC-MS) was developed in order to investigate the metabolites characters of systemic lupus erythematosus (SLE) and therapeutic effects of jieduquyuziyin prescription (JP). The urinary metabolic profiles in urine specimens of the SLE model mice (MRL/lpr) group, prednisone acetate (PA)-treated SLE mice group, JP-treated SLE mice group, and control group (C57BL/6 J) after the administration were analyzed by GC-MS. These metabolic profiles were then processed by multivariate analysis, in particular Mass Profiler Professional (MPP), SIMCA-P and partial least-squares discriminant analysis (PLS-DA). According to the PLS-DA results, the SLE model group and the control group were obviously separated, indicating that the incidence of SLE had a greater impact on the metabolic network, and the SLE model group had significant difference compared with the control group in urine metabolites. 11 differential metabolites were identified to be related to SLE. And the results of differential metabolite identification showed that the metabolites were mainly related to energy metabolism and amino acid metabolism pathway. These results can provide an experimental basis for further exploring the mechanism of traditional Chinese medicine (TCM) in the treatment of SLE.

A proteomics method using immunoaffinity fluorogenic derivatization–liquid chromatography/tandem mass spectrometry (FD-LC-MS/MS) to identify a set of interacting proteins

Biological functions in organisms are usually controlled by a set of interacting proteins, and identifying the proteins that interact is useful for understanding the mechanism of the functions. Immunoprecipitation is a method that utilizes the affinity of an antibody to isolate and identify the proteins that have interacted in a biological sample. In this study, the FD-LC–MS/MS method, which involves fluorogenic derivatization followed by separation and quantification by HPLC and finally identification of proteins by HPLC–tandem mass spectrometry, was used to identify proteins in immunoprecipitated samples, using heat shock protein 90 (HSP90) as a model of an interacting protein in HepaRG cells. As a result, HSC70 protein, which was known to form a complex with HSP90, was isolated, together with three different types of HSP90-beta. The results demonstrated that the proposed immunoaffinity–FD-LC–MS/MS method could be useful for simultaneously detecting and identifying the proteins that interact with a certain protein.

Abstract

Biological functions in organisms are usually controlled by a set of interacting proteins, and identifying the proteins that interact is useful for understanding the mechanism of the functions. Immunoprecipitation is a method that utilizes the affinity of an antibody to isolate and identify the proteins that have interacted in a biological sample. In this study, the FD-LC–MS/MS method, which involves fluorogenic derivatization followed by separation and quantification by HPLC and finally identification of proteins by HPLC–tandem mass spectrometry, was used to identify proteins in immunoprecipitated samples, using heat shock protein 90 (HSP90) as a model of an interacting protein in HepaRG cells. As a result, HSC70 protein, which was known to form a complex with HSP90, was isolated, together with three different types of HSP90-beta. The results demonstrated that the proposed immunoaffinity–FD-LC–MS/MS method could be useful for simultaneously detecting and identifying the proteins that interact with a certain protein.

Employment of modified Fe3O4 nanoparticles using thermo-sensitive polymer for extraction and pre-concentration of cefexime in biological samples

Cefexime is a useful antibiotic that can be prescribed to treat bacterial infections. Nanoparticles have been widely marketed as a universal solution among scientists. Many studies have been performed to modify nanoparticles to make them functional as extraction and pre-concentration agents and drug carriers. Temperature-sensitive polymers belong to a group of substances that undergo a major change in their physical features in response to temperature. Recently developed polymers can be used in many different areas, including modification of nanoparticles. In order to modify this nanoparticle, grafting copolymerization of Fe3O4 nanoparticles was performed using poly (N-vinylcaprolactam) and 3-allyloxy-1,2-propanediol. The optimum conditions for pre-concentration of cefexime were studied. Under these optimum conditions, extraction recovery of biological samples in the range of 71–89% was obtained. The limit of detection and precision of proposed method were 4.5 × 10−4 μg mL−1 and <4.11% (relative standard deviation), respectively. Based on the results from analysis of cefexime, in biological samples using the proposed method, the ability of this method to extract and pre-concentrate cefexime was confirmed. Also, satisfactory results from an in vitro study on drug release in simulated intestine media were obtained.

Abstract

Cefexime is a useful antibiotic that can be prescribed to treat bacterial infections. Nanoparticles have been widely marketed as a universal solution among scientists. Many studies have been performed to modify nanoparticles to make them functional as extraction and pre-concentration agents and drug carriers. Temperature-sensitive polymers belong to a group of substances that undergo a major change in their physical features in response to temperature. Recently developed polymers can be used in many different areas, including modification of nanoparticles. In order to modify this nanoparticle, grafting copolymerization of Fe3O4 nanoparticles was performed using poly (N-vinylcaprolactam) and 3-allyloxy-1,2-propanediol. The optimum conditions for pre-concentration of cefexime were studied. Under these optimum conditions, extraction recovery of biological samples in the range of 71–89% was obtained. The limit of detection and precision of proposed method were 4.5 × 10−4 μg mL−1 and <4.11% (relative standard deviation), respectively. Based on the results from analysis of cefexime, in biological samples using the proposed method, the ability of this method to extract and pre-concentrate cefexime was confirmed. Also, satisfactory results from an in vitro study on drug release in simulated intestine media were obtained.

Quantitative analysis of clofazimine (Lamprene®), an antileprosy agent, in human dried blood spots using liquid chromatography–tandem mass spectrometry

An LC–MS/MS method was developed and validated for bioanalysis of clofazimine in human dried blood spot (DBS) samples in support of a clinical study on multidrug-resistant tuberculosis in developing countries. The validated assay dynamic range was from 10.0 to 2000 ng/mL using a 1/8 inch DBS punch. The accuracy and precision of the assay were ±11.0% (bias) and ≤13.5% (CV) for the LLOQs (10.0 ng/mL) and ±15% (bias) and ≤15% (CV) for all other QC levels. The assay was proved to be free from the possible impact owing to spot size and storage temperature (e.g. at 60°C, ≤ − 60°C). The validated assay is well suited for the intended clinical study where conventional pharmacokinetic sample collection is not feasible.

Abstract

An LC–MS/MS method was developed and validated for bioanalysis of clofazimine in human dried blood spot (DBS) samples in support of a clinical study on multidrug-resistant tuberculosis in developing countries. The validated assay dynamic range was from 10.0 to 2000 ng/mL using a 1/8 inch DBS punch. The accuracy and precision of the assay were ±11.0% (bias) and ≤13.5% (CV) for the LLOQs (10.0 ng/mL) and ±15% (bias) and ≤15% (CV) for all other QC levels. The assay was proved to be free from the possible impact owing to spot size and storage temperature (e.g. at 60°C, ≤ − 60°C). The validated assay is well suited for the intended clinical study where conventional pharmacokinetic sample collection is not feasible.

Simultaneous determination of morphine-6-d-glucuronide, morphine-3-d-glucuronide and morphine in human plasma and urine by ultra-performance liquid chromatography–tandem mass spectrometry: Application to M6G injection pharmacokinetic study

A robust ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for the determination of morphine-6-d-glucuronide (M6G), morphine-3-d-glucuronide (M3G) and morphine (MOR) in human plasma and urine has been developed and validated. The analytes of interest were extracted from plasma by protein precipitation. The urine sample was prepared by dilution. Both plasma and urine samples were chromatographed on an Acquity UPLC HSS T3 column using gradient elution. Detection was performed on a Xevo TQ-S tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. Matrix interferences were not observed at the retention time of the analytes and internal standard, naloxone-D5. The lower limits of quantitation of plasma and urine were 2/0.5/0.5 and 20/4/2 ng/mL for M6G/M3G/MOR, respectively. Calibration curves were linear over the concentration ranges of 2–2000/0.5–500/0.5–500 and 20–20,000/4–4000/2–2000 ng/mL for M6G/M3G/MOR in plasma and urine samples, respectively. The precision was <7.14% and the accuracy was within 85–115%. Furthermore, stability of the analytes at various conditions, dilution integrity, extraction recovery and matrix effect were assessed. Finally, this quantitative method was successfully applied to the pharmacokinetic study of M6G injection in Chinese noncancer pain patients.

Abstract

A robust ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for the determination of morphine-6-d-glucuronide (M6G), morphine-3-d-glucuronide (M3G) and morphine (MOR) in human plasma and urine has been developed and validated. The analytes of interest were extracted from plasma by protein precipitation. The urine sample was prepared by dilution. Both plasma and urine samples were chromatographed on an Acquity UPLC HSS T3 column using gradient elution. Detection was performed on a Xevo TQ-S tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. Matrix interferences were not observed at the retention time of the analytes and internal standard, naloxone-D5. The lower limits of quantitation of plasma and urine were 2/0.5/0.5 and 20/4/2 ng/mL for M6G/M3G/MOR, respectively. Calibration curves were linear over the concentration ranges of 2–2000/0.5–500/0.5–500 and 20–20,000/4–4000/2–2000 ng/mL for M6G/M3G/MOR in plasma and urine samples, respectively. The precision was <7.14% and the accuracy was within 85–115%. Furthermore, stability of the analytes at various conditions, dilution integrity, extraction recovery and matrix effect were assessed. Finally, this quantitative method was successfully applied to the pharmacokinetic study of M6G injection in Chinese noncancer pain patients.

Development and validation of a high-performance liquid chromatography method for the quantification of talazoparib in rat plasma: Application to plasma protein binding studies

A sensitive and selective RP-HPLC method has been developed and validated for the quantification of a highly potent poly ADP ribose polymerase inhibitor talazoparib (TZP) in rat plasma. Chromatographic separation was performed with isocratic elution method. Absorbance for TZP was measured with a UV detector (SPD-20A UV–vis) at a λmax of 227 nm. Protein precipitation was used to extract the drug from plasma samples using methanol–acetonitrile (65:35) as the precipitating solvent. The method proved to be sensitive and reproducible over a 100–2000 ng/mL linearity range with a lower limit of quantification (LLQC) of 100 ng/mL. TZP recovery was found to be >85%. Following analytical method development and validation, it was successfully employed to determine the plasma protein binding of TZP. TZP has a high level of protein binding in rat plasma (95.76 ± 0.38%) as determined by dialysis method.

Abstract

A sensitive and selective RP-HPLC method has been developed and validated for the quantification of a highly potent poly ADP ribose polymerase inhibitor talazoparib (TZP) in rat plasma. Chromatographic separation was performed with isocratic elution method. Absorbance for TZP was measured with a UV detector (SPD-20A UV–vis) at a λmax of 227 nm. Protein precipitation was used to extract the drug from plasma samples using methanol–acetonitrile (65:35) as the precipitating solvent. The method proved to be sensitive and reproducible over a 100–2000 ng/mL linearity range with a lower limit of quantification (LLQC) of 100 ng/mL. TZP recovery was found to be >85%. Following analytical method development and validation, it was successfully employed to determine the plasma protein binding of TZP. TZP has a high level of protein binding in rat plasma (95.76 ± 0.38%) as determined by dialysis method.

Application of gas and liquid chromatography coupled to time-of-flight mass spectrometry in pesticides: Multiresidue analysis

Analysis of pesticide residues in water and food matrices is an active research area closely related to food safety and environmental issues. In this aspect mass spectrometry (MS) coupled to gas chromatography (GC) and liquid chromatography (LC) has been increasingly used in the analysis of pesticide residues in water and food. The increasing interest in application of high-resolution mass spectrometry with time-of-flight (TOF) and hybrid triple quadrupole TOF in pesticide analysis is due to its capability of performing both targeted and nontargeted analysis. This article discusses an overview of the application of GC-TOF-MS and LC-TOF-MS in water and food matrices.

Abstract

Analysis of pesticide residues in water and food matrices is an active research area closely related to food safety and environmental issues. In this aspect mass spectrometry (MS) coupled to gas chromatography (GC) and liquid chromatography (LC) has been increasingly used in the analysis of pesticide residues in water and food. The increasing interest in application of high-resolution mass spectrometry with time-of-flight (TOF) and hybrid triple quadrupole TOF in pesticide analysis is due to its capability of performing both targeted and nontargeted analysis. This article discusses an overview of the application of GC-TOF-MS and LC-TOF-MS in water and food matrices.

Quantification of β-eudesmol in rat plasma using LC–MS/MS and its application to a pharmacokinetic study

A sensitive and specific LC–MS/MS assay for determination of β-eudesmol in rat plasma was developed and validated. After liquid–liquid extraction with ethyl ether, the analyte and IS were separated on a Capcell Pak C18 column (50 × 2.0 mm, 5 μm) by isocratic elution with acetonitrile—water–formic acid (77.5:22.5:0.1, v/v/v) as the mobile phase at a flow rate of 0.4 mL/min. An ESI source was applied and operated in positive ion mode; a selected reaction monitoring scan was used for quantification by monitoring the precursor–product ion transitions of m/z 245.1  163.1 for β-eudesmol and m/z 273.4  81.2 for IS. Good linearity was observed in the concentration range of 3–900 ng/mL for β-eudesmol in rat plasma. Intra- and inter-day precision and accuracy were both within ±14.3%. This method was applied for pharmacokinetic studies after intravenous bolus of 2.0 mg/kg or intragastric administration of 50 mg/kg β-eudesmol in rats.

Abstract

A sensitive and specific LC–MS/MS assay for determination of β-eudesmol in rat plasma was developed and validated. After liquid–liquid extraction with ethyl ether, the analyte and IS were separated on a Capcell Pak C18 column (50 × 2.0 mm, 5 μm) by isocratic elution with acetonitrile—water–formic acid (77.5:22.5:0.1, v/v/v) as the mobile phase at a flow rate of 0.4 mL/min. An ESI source was applied and operated in positive ion mode; a selected reaction monitoring scan was used for quantification by monitoring the precursor–product ion transitions of m/z 245.1 [RIGHTWARDS ARROW] 163.1 for β-eudesmol and m/z 273.4 [RIGHTWARDS ARROW] 81.2 for IS. Good linearity was observed in the concentration range of 3–900 ng/mL for β-eudesmol in rat plasma. Intra- and inter-day precision and accuracy were both within ±14.3%. This method was applied for pharmacokinetic studies after intravenous bolus of 2.0 mg/kg or intragastric administration of 50 mg/kg β-eudesmol in rats.