A sensitive assay for the determination of E7090, a novel selective inhibitor of fibroblast growth factor receptors, and its metabolite in human plasma by UPLC-MS/MS with at-column dilution

E7090, a novel fibroblast growth factor receptors inhibitor, is currently under clinical development for the treatment of patients with solid tumors. The previous assay was insufficient in detection sensitivity for E7090 and high exposure of a dealkylated metabolite, M2, was noted in a clinical trial at low doses. Thus, a sensitive assay for the simultaneous determination of E7090 and M2 in human plasma has been developed using ultra-performance liquid chromatography with tandem mass spectrometer (UPLC-MS/MS). E7090 and M2 were extracted from 0.1 mL of plasma by protein precipitation and chromatographed on a reverse phase column utilizing at-column dilution which enables larger volume sample injection to the UPLC-MS/MS. E7090 and M2 were quantifiable from 0.025 ng/mL, which was 40-fold higher sensitivity than the previous assay. Accuracy as relative error and precision as relative standard deviation were within ± 15% and 15%, respectively, ensuring the reproducibility of the assay. The developed assay method was applied to a clinical trial of E7090, and plasma concentrations of E7090 and M2 were quantifiable up to 144 h postdose. These results indicated that the developed more sensitive assay was reproducible and was successfully applied to a clinical trial of E7090.

The Use of Dried Blood Spots for the Quantification of Antihypertensive Drugs

Hypertension or high blood pressure is a harbinger of cardiovascular diseases. There are several classes of drugs used to treat hypertension. This review discusses the use of dried blood spots (DBSs) for the quantification by mass spectrometry (MS), tandem mass spectrometry (MS/MS), or, in some cases, by fluorescence detection methods the following antihypertensive medications: angiotensin-converting enzyme inhibitors (ramipril, ramiprilat, captopril, and lisinopril); angiotensin II receptor antagonists (valsartan, irbesartan, losartan, and losartan carboxylic acid); calcium channel blockers (verapamil, amlodipine, nifedipine, pregabalin, and diltiazem); α blockers (guanfacine, doxazosin, and prazosin); β blockers (propranolol, bisoprolol, atenolol, and metoprolol); endothelin receptor antagonists (bosentan and ambrisentan); and statins (simvastatin, atorvastatin, and rosuvastatin).

New on-line separation workflow of microbial metabolites via hyphenation of analytical and preparative comprehensive two-dimensional liquid chromatography

Microbial metabolites represent an important source of bioactive natural products, but always exhibit diverse of chemical structures or complicated chemical composition with low active ingredients content. Traditional separation methods rely mainly on off-line combination of open-column chromatography and preparative high performance liquid chromatography (HPLC). However, the multi-step and prolonged separation procedure might lead to exposure to oxygen and structural transformation of metabolites. In the present work, a new two-dimensional separation workflow for fast isolation and analysis of microbial metabolites from Chaetomium globosum SNSHI-5, a cytotoxic fungus derived from extreme environment. The advantage of this analytical comprehensive two-dimensional liquid chromatography (2D-LC) lies on its ability to analyze the composition of the metabolites, and to optimize the separation conditions for the preparative 2D-LC. Furthermore, gram scale preparative 2D-LC separation of the crude fungus extract could be performed on a medium-pressure liquid chromatograph×preparative high-performance liquid chromatography system, under the optimized condition. Interestingly, 12 cytochalasan derivatives, including two new compounds named cytoglobosin Ab (3) and isochaetoglobosin Db (8), were successfully obtained with high purity in a short period of time. The structures of the isolated metabolites were comprehensively characterized by HR ESI-MS and NMR. To be highlighted, this is the first report on the combination of analytical and preparative 2D-LC for the separation of microbial metabolites. The new workflow exhibited apparent advantages in separation efficiency and sample treatment capacity compared with conventional methods.

Cardiovascular drug determination in bioanalysis: an update

The great impact of cardiovascular diseases in human health has led to the development of a huge number of drugs and therapies to improve the treatment of these diseases. Cardiovascular drug analysis in biological fluids constitutes an important challenge for analytical scientists. There is a clear need for reliable methods to carry out both qualitative and quantitative analysis in a short time of analysis. Different problems such as drug monitoring, analysis of metabolites, study of drugs interactions, drugs residues or degradation products, chiral separation, and screening and confirmation of drugs of abuse in doping control must be solved. New trends in sample preparation, instrumental and column technology advances in LC and innovations in MS are described in this work.