Rapid validated liquid chromatographic method coupled with Tandem mass spectrometry for quantification of nintedanib in human plasma

Purpose: To develop and validate a fast, sensitive, and simple liquid chromatographic method coupled with tandem mass spectrometry for the determination of the potent tyrosine kinase inhibitor, ninetedanib (NTB) in plasma, utilizing cyclobenzaprine (CBP) as internal standard (IS).Methods: Separation of the two components (NTB and CBP) was performed on a pentafluorophenyl (PFP) reversed phase column (50 × 2 mm, 3μm) at ambient temperature using isocratic elution with acetonitrile-water (60:40, v/v) containing 0.01 M ammonium formate buffer (pH 4.2) at a flow rate of 0.4 mL/min. NTB and CBP were monitored by a triple quadrupole tandem mass spectrometer with electrospray ionization source in the positive ion mode. The current method was validated following the European Medicines Agency (EMA) guidelinesResults: The proposed method allowed rapid and specific quantification of NTB in the calibration range of 2 - 150 ng/mL and determination coefficient of ≥ 0.999. Intra- and inter-day accuracy and precision were < 4 % in all cases.Conclusion: The developed procedure is rapid, specific, reliable, and validated for quantification of NTB in human plasma, and thus can be applied efficiently for the analysis of clinical samples containing NTB.Keywords: Nintedanib assay, Cyclobenzaprine, LC-MS/MS, Validatio

Liquid chromatographic-tandem mass spectrometric assay for simultaneous quantitation of tofacitinib, cabozantinib and afatinib in human plasma and urine

Purpose: To develop a simple, adequately sensitive, and practical liquid chromatographic-mass spectrometric method to simultaneously quantify three tyrosine kinase inhibitors, viz, tofacitinib (TOF), cabozantinib (CBZ) and afatinib (AFB) after their extraction from both human plasma and urine.Methods: Blood and urine samples were obtained from healthy volunteers who admitted to not being on any medications. The investigated analytes were chromatographically separated on a C18 column (Luna®-PFP 100Å column, 50 mm × 2.0 mm i.d., 3.0 μm) with the aid of a mobile phase containing A; acetonitrile (ACN) and B; 0.01 M ammonium formate buffer (pH 4.1) pumped at a rate of 0.3 mL.min-1 in the ratio A:B, 50:50 v/v. Analyte monitoring was achieved by tandem mass spectrometry interfaced with an electrospray ionization source with the aid of multiple reaction monitoring (MRM) mode for analytes quantification.Results: The proposed method permitted a specific and sensitive determination of the investigated TKIs in the linear range of 1.0 - 100 ng mL-1 with correlation coefficient (r2) of 0.9991, 0.9997, and 0.9998 for TOF, CBZ and AFB, respectively. The method was validated with regard to its limits of quantification (ranging from 0.91 to 1.24 ng mL-1 for the 3 analytes), intra- and inter assay accuracy (in the range -1.85 to 1.22 %) and precision (0.71 - 5.12 %). The method was also validated in terms of recovery from both studied matrices, robustness and matrix effect.Conclusion: The results obtained reveal that the developed method is simple, specific and highly efficient for routine determination of the studied analytes in human plasma and urine. It can be reliably applied for high throughput analysis of clinical samples containing the investigated analytes.Keywords: Tyrosine kinase inhibitors, Tofacitinib, Cabozantinib, Afatinib, LC-MS/MS, human plasm

Liquid chromatographic-mass spectrometric method for determination of drug content uniformity of two commonly used dermatology medications in a split-tablet dosage form

Purpose: To develop and validate a simple, efficient and reliable Liquid  chromatographic-mass spectrometric (LC-MS/MS) method for the quantitative determination of two dermatological drugs, Lamisil® (terbinafine) and Proscar® (finasteride), in split tablet dosage form.Methods: Thirty tablets each of the 2 studied medications were randomly selected. Tablets were weighed and divided into 3 groups. Ten tablets of each drug were kept intact, another group of 10 tablets were manually split into halves using a tablet cutter and weighed with an analytical balance; a third group were split into quarters and weighed. All intact and split tablets were individually dissolved in a water: methanol mixture (4:1), sonicated, filtered and further diluted with mobile phase. Optimal chromatographic separation and mass spectrometric detection were achieved using an Agilent 1200 HPLC system coupled with an Agilent 6410 triple quadrupole mass spectrometer. Analytes were eluted through an Agilent eclipse plus C8 analytical column (150 mm × 4.6 mm, 5 μm) with a mobile phase composed of solvent A (water) containing 0.1% formic acid and 5mM ammonium formate pH 7.5, and solvent B (acetonitrile mixed with water in a ratio A:B 55:45) at a flow rate of 0.8 mL min-1 with a total run time of 12 min. Mass spectrometric detection was carried out using positive ionization mode with analyte quantitation monitored by multiple reaction monitoring (MRM) mode.Results: The proposed analytical method proved to be specific, robust and  adequately sensitive. The results showed a good linear fit over the concentration range of 20 - 100 ng mL-1 for both analytes, with a correlation coefficient (r2) ≥ 0.999 and 0.998 for finasteride and terbinafine, respectively. Following tablet splitting, the drug content of the split tablets fell outside of the proxy USP  specification for at least 14 halves (70 %) and 34 quarters (85 %) of FIN, as well as 16 halves (80 %) and 37 quarters (92.5 %) of TBN. Mean weight loss, after splitting, was 0.58 and 2.22 % for FIN half- and quarter tablets, respectively, and 3.96 and 4.09 % for TBN half- and quarter tablets,respectively.Conclusion: The proposed LC-MS/MS method has successfully been used to provide precise drug content uniformity of split tablets of FIN and TBN. Unequal distribution of the drug on the split tablets is indicated by the high standard deviation beyond the accepted value. Hence, it is recommended not to split non-scored tablets  especially, for those medications with significant toxicityKeywords: Tablet splitting, Finasteride, Terbinafine, Drug content uniformity,  LC-MS/M

Multistage Fragmentation of Ion Trap Mass Spectrometry System and Pseudo-MS 3

A new approach was recently introduced to improve the structure elucidation power of tandem mass spectrometry simulating the MS3 of ion trap mass spectrometry system overcoming the different drawbacks of the latter. The fact that collision induced dissociation in the triple quadrupole mass spectrometer system provides richer fragment ions compared to those achieved in the ion trap mass spectrometer system utilizing resonance excitation. Moreover, extracting comprehensive spectra in the ion trap needs multistage fragmentation, whereas similar fragment ions may be acquired from one stage product ion scan using the triple quadrupole mass spectrometer. The new strategy was proven to enhance the qualitative performance of tandem mass spectrometry for structural elucidation of different chemical entities. In the current study we are endeavoring to prove our hypothesis of the efficiency of the new pseudo-MS3 technique via its comparison with the MS3 mode of ion trap mass spectrometry system. Ten pharmacologically and synthetically important (E)-3-(dimethylamino)-1-arylprop-2-en-1-ones (enaminones 4a–j) were chosen as model compounds for this study. This strategy permitted rigorous identification of all fragment ions using triple quadrupole mass spectrometer with sufficient specificity. It can be used to elucidate structures of different unknown components. The data presented in this paper provide clear evidence that our new pseudo-MS3 may simulate the MS3 of ion trap spectrometry system

Development of an LC-MS/MS Method for Quantification of Sapitinib in Human Liver Microsomes: In Silico and In Vitro Metabolic Stability Evaluation

Sapitinib (AZD8931, SPT) is a tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR) family (pan-erbB). In multiple tumor cell lines, STP has been shown to be a much more potent inhibitor of EGF-driven cellular proliferation than gefitinib. In the current study, a highly sensitive, rapid, and specific LC-MS/MS analytical method for the estimation of SPT in human liver microsomes (HLMs) was established with application to metabolic stability assessment. The LC-MS/MS analytical method was validated in terms of linearity, selectivity, precision, accuracy, matrix effect, extraction recovery, carryover, and stability following the FDA guidelines for bioanalytical method validation. SPT was detected using electrospray ionization (ESI) as an ionization source under multiple reaction monitoring (MRM) in the positive ion mode. The IS-normalized matrix factor and extraction recovery were acceptable for the bioanalysis of SPT. The SPT calibration curve was linear, from 1 ng/mL to 3000 ng/mL HLM matrix samples, with a linear regression equation of y = 1.7298x + 3.62941 (r2 = 0.9949). The intraday and interday accuracy and precision values of the LC-MS/MS method were −1.45–7.25% and 0.29–6.31%, respectively. SPT and filgotinib (FGT) (internal standard; IS) were separated through the use of an isocratic mobile phase system with a Luna 3 µm PFP(2) column (150 × 4.6 mm) stationary phase column. The limit of quantification (LOQ) was 0.88 ng/mL, confirming the LC-MS/MS method sensitivity. The intrinsic clearance and in vitro half-life of STP were 38.48 mL/min/kg and 21.07 min, respectively. STP exhibited a moderate extraction ratio that revealed good bioavailability. The literature review demonstrated that the current analytical method is the first developed LC-MS/MS method for the quantification of SPT in an HLM matrix with application to SPT metabolic stability evaluation

Rapid LC-MS/MS Bosutinib Quantification with Applications in Metabolic Stability Estimation

Bosutinib (BOS) is FDA approved drug for the treatment of chronic phase (CP) Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia (CML). We report a fast, sensitive, and simple LC-MS/MS method, validated for the determination of BOS in human liver microsomes, utilizing tofacitinib (TOF) as the internal standard. The separation of BOS and TOF was done using a 1.8 μm C18 column (2.1 × 50 mm) at room temperature using the isocratic elution system of acetonitrile–water (30:70, v/v) containing 0.1 M formic acid at a flow rate of 0.15 mL/min, and a triple-quadrupole tandem mass spectrometer (TQD-MS) with an electrospray ionization (ESI) source that was operated in the positive ion mode. The method was validated according to the European Medicines Agency, and the rapid and specific quantification of BOS in human liver microsomes was achieved in the range of 5–200 ng/mL, with a determination coefficient of 0.999. Intra- and inter-day accuracy and precision values were int (34.3 µL/min/mg) and short in vitro t1/2 values of 20.21 min, indicating that BOS may be rapidly eliminated from the blood by the liver

Rapid LC-MS/MS Bosutinib Quantification with Applications in Metabolic Stability Estimation

Bosutinib (BOS) is FDA approved drug for the treatment of chronic phase (CP) Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia (CML). We report a fast, sensitive, and simple LC-MS/MS method, validated for the determination of BOS in human liver microsomes, utilizing tofacitinib (TOF) as the internal standard. The separation of BOS and TOF was done using a 1.8 μm C18 column (2.1 × 50 mm) at room temperature using the isocratic elution system of acetonitrile–water (30:70, v/v) containing 0.1 M formic acid at a flow rate of 0.15 mL/min, and a triple-quadrupole tandem mass spectrometer (TQD-MS) with an electrospray ionization (ESI) source that was operated in the positive ion mode. The method was validated according to the European Medicines Agency, and the rapid and specific quantification of BOS in human liver microsomes was achieved in the range of 5–200 ng/mL, with a determination coefficient of 0.999. Intra- and inter-day accuracy and precision values were <4% in all cases. The procedure is rapid, specific, reliable, and can be applied in metabolic stability evaluations since it is the first LC-MS/MS method specific to BOS quantification. The metabolic stability assessment of BOS showed high CLint (34.3 µL/min/mg) and short in vitro t1/2 values of 20.21 min, indicating that BOS may be rapidly eliminated from the blood by the liver

Identification of Iminium Intermediates Generation in the Metabolism of Tepotinib Using LC-MS/MS: In Silico and Practical Approaches to Bioactivation Pathway Elucidation

Tepotinib (Tepmetko™, Merck) is a potent inhibitor of c-Met (mesenchymal−epithelial transition factor). In March 2020, tepotinib (TEP) was approved for use in Japan for the treatment of patients who suffered from non-small cell lung cancers (NSCLC) harboring an MET exon 14 skipping alteration and have progressed after platinum-based therapy. Practical and in silico experiments were used to screen for the metabolic profile and reactive intermediates of TEP. Knowing the bioactive center and structural alerts in the TEP structure helped in making targeted modifications to improve its safety. First, the prediction of metabolism vulnerable sites and reactivity metabolic pathways was performed using the StarDrop WhichP450™ module and the online Xenosite reactivity predictor tool, respectively. Subsequently, in silico data were used as a guide for the in vitro practical work. Second, in vitro phase I metabolites of TEP were generated from human liver microsome (HLM) incubations. Testing for the generation of unstable reactive intermediates was performed using potassium cyanide as a capturing agent forming stable cyano adduct that can be characterized and identified using liquid chromatography tandem mass spectrometry (LC-MS/MS). Third, in silico toxicity assessment of TEP metabolites was performed, and structural modification was proposed to decrease their side effects and to validate the proposed bioactivation pathway using the DEREK software. Four TEP phase I metabolites and four cyano adducts were characterized. The reactive intermediate generation mechanism of TEP may provide an explanation of its adverse reactions. The piperidine ring is considered a structural alert for toxicity as proposed by the DEREK software and a Xenosite reactivity model, which was confirmed by practical experiments. Steric hindrance or isosteric replacement at α-carbon of the piperidine ring stop the bioactivation sequence that was confirmed using the DEREK software. More drug discovery studies can be performed using this perception permitting the design of new drugs with an increased safety profile. To our knowledge, this is the first study for the identification of in vitro phase I metabolites and reactive intermediates in addition to toxicological properties of the metabolites for TEP that will be helpful for the evaluation of TEP side effects and drug–drug interactions in TEP-treated patients

Characterization of in vivo metabolites in rat urine following an oral dose of masitinib by liquid chromatography tandem mass spectrometry

Abstract Masitinib (MST) is an orally administered drug that targets mast cells and macrophages, important cells for immunity, by inhibiting a limited number of tyrosine kinases. It is currently registered in Europe and USA for the treatment of mast cell tumors in dogs. AB Science announced that the European Medicines Agency has accepted a conditional marketing authorization application for MST to treat amyotrophic lateral sclerosis. In our work, we focused on studying in vivo metabolism of MST in Sprague–Dawley rats. Single oral dose of MST (33 mg kg−1) was given to Sprague–Dawley rats (kept in metabolic cages) using oral gavage. Urine was collected and filtered at 0, 6, 12, 18, 24, 48, 72 and 96 h from MST dosing. An equal amount of ACN was added to urine samples. Both organic and aqueous layers were injected into liquid chromatography-tandem mass spectrometry (LC–MS/MS) to detect in vivo phase I and phase II MST metabolites. The current work reports the identification and characterization of twenty in vivo phase I and four in vivo phase II metabolites of MST by LC–MS/MS. Phase I metabolic pathways were reduction, demethylation, hydroxylation, oxidative deamination, oxidation and N-oxide formation. Phase II metabolic pathways were the direct conjugation of MST, N-demethyl metabolites and oxidative metabolites with glucuronic acid. Part of MST dose was excreted unchanged in urine. The literature review showed no previous articles have been made on in vivo metabolism of MST or detailed structural identification of the formed in vivo phase I and phase II metabolites