Developing a robust LC-MS/MS method to quantify Zn-DTPA, a zinc chelate in human plasma and urine.

Quantitation of Zn-DTPA (zinc diethylenetriamene pentaacetate, a metal chelate) in complex biological matrix is extremely challenging on account of its special physiochemical properties. This study aimed to develop a robust and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of Zn-DTPA in human plasma and urine. The purified samples were separated on Proteonavi (250 × 4.

Simultaneous quantification of tizoxanide and tizoxanide glucuronide in mouse plasma by liquid chromatography-tandem mass spectrometry.

Nitazoxanide (NTZ) is a broad-spectrum antimicrobial agent. Tizoxanide (T) and tizoxanide glucuronide (TG) are the major circulating metabolites after oral administration of NTZ. A rapid and specific LC-MS/MS method for the simultaneous quantification of T and TG in mouse plasma was developed and validated.

A sensitive LC-MS/MS method for quantifying capsaicin and dihydrocapsaicin in rabbit plasma and tissue: application to a pharmacokinetic study.

Prescription and nonprescription products for topical management of pain, including cream, lotion and patch forms, contain capsaicin (CAP) and dihydrocapsaicin (DHC). There are few in vivo studies on absorption, bioavailability and disposition of CAP and DHC. We established a sensitive and rapid LC-MS/MS assay to determine CAP and DHC levels in rabbit plasma and tissue.

Determination of alamifovir disoproxil fumarate and its active metabolite 602076 in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

Alamifovir disoproxil fumarate (ADF) is a novel ester prodrug of alamifovir, which is currently as a promising antiviral candidate under investigation. This paper is aimed to develop rapid, sensitive and specific LC-MS/MS methods for the quantification of ADF and its active metabolite 602076 in rat plasma. According to the significantly different chemical properties of the compounds, two sets of liquid chromatography and ionization modes were used for determining the concentration of ADF and 602076 in rat plasma, separately.

Development of a sensitive liquid chromatography/tandem mass spectrometry method for the determination of fenofibric acid in rat plasma.

A rapid and sensitive LC-MS/MS method for the quantification of fenofibric acid in rat plasma was developed and validated. Plasma samples were prepared by liquid-liquid extraction with a mixture of N-hexane-dichloromethane-isopropanol (100:50:5, v/v/v). Isocratic chromatographic separation was performed on a reversed-phase Discovery C(18) column (2.

Development and validation of an LC/MS/MS method for the determination of tenofovir in monkey plasma.

A simple, specific, sensitive LC/MS/MS method for the quantitation of tenofovir (TFV) in monkey plasma was developed and validated. After the addition of adefovir as an internal standard (IS), methanol was used to produce a protein-free extract. Isocratic chromatographic separation was performed on a reverse-phase Discovery C(18) column (4.

Simultaneous quantification of tracheloside and trachelogenin in rat plasma using liquid chromatography/tandem mass spectrometry.

We developed and validated a quantitative method for simultaneously determining the concentrations of tracheloside and trachelogenin in rat plasma. Plasma samples were prepared by liquid-liquid extraction with ethyl acetate. Isocratic chromatographic separation was performed on a reversed-phase Diamonsil C(18) column (4.

[Determination of icaritin in rat plasma by HPLC-MS/MS].

The paper is to report the development of a high-performance liquid chromatographic/tandem mass spectrometry (HPLC-MS/MS) method for the determination of icaritin (ICT) in rat plasma. After precipitated with acetonitrile from the plasma, ICT was isolated chromatographically on a Dikma C18 column. The mobile phase consisted of acetonitrile-water-acetic acid (72 : 28 : 1.

Pharmacokinetics and tissue distribution of a water-soluble flavonol triglycoside, CTN986, in mice.

The pharmacokinetics and bioavailability of CTN986, a highly water-soluble flavonol triglycoside that has shown interesting antidepressant effects, were determined in mice after intravenous ( I. V.), intraperitoneal ( I.

[Studies on bioassay-guided anti-inflammatory fraction in bark of Albizia julibrissin combined determination with LC-MS-MS].

Objective: To search the anti-inflammatory fraction of Albizia julibrissin.

Method: Inflammatory model of Kunming mice ear edema induced by croton oil and determination combined with the LC-MS-MS-guided fractionation and isolation were used.

Result: The n-butanol fraction (AJ-B) obtained from the ethanolic extract of the Cortex albiziae was the major active fraction.

Simultaneous quantification of CTN986 and its deglycosylation products in rat serum using liquid chromatography/tandem mass spectrometry.

A quantitative method for the simultaneous determination of CTN986, a flavonol triglycoside, and its two deglycosylation products rutin and hirsutin in rat serum was developed and validated for the investigation of the pharmacokinetics of CTN986. Analytes were isolated from the serum samples (200 microL) prior to analysis by liquid chromatography/tandem mass spectrometry (LC/MS/MS) using C(18) solid-phase extraction, and were separated on a Zorbax C(8) reversed-phase column with an isocratic mobile phase consisting of methanol/isopropanol/water/formic acid (20:10:70:0.1, v/v/v/v).

Chiral melamine derivatives: design, synthesis, and application to mass spectrometry-based chiral analysis.

A novel class of chiral melamine derivatives has been designed and synthesized. The ability of these compounds to perform chiral recognition toward 19 natural chiral alpha-amino acids has been investigated by electrospray ionization tandem mass spectrometry for the first time. The enantioselectivities of these new chiral selectors are encouraging.

[Rapid identification of the isomeric impurity in raw drug of cefepime dihydrochloride by liquid chromatography-tandem mass spectrometry].

Aim: To establish a sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of isomeric impurity in raw drug material of cefepime dihydrochloride.

Methods: The HPLC separation experiments were performed on a reversed phase C18 column, with acetonitrile-10 mmol x L(-1) ammonium acetate (5:95) as mobile phase (a flow rate of 0.8 mL x min(-1)).

Determination of rizatriptan in human plasma by liquid chromatographic-eletrospray tandem mass spectrometry: application to a pharmacokinetic study.

A sensitive liquid chromatographic-tandem mass spectrometry(LC-MS/MS) method was developed for the determination of rizatriptan in human plasma. The analytes were extracted from plasma samples by liquid-liquid extraction, separated on a Zorbax XDB C8 column (150 x 4.6 mm i.

Identification of rat faecal, urinary and biliary metabolites of thionorphine, a novel mixed agonist-antagonist analgesic, using liquid chromatography/electrospray ionization tandem mass spectrometry.

The biotransformation of thionorphine (N-cyclopropylmethyl-7alpha-[(s)-1-hydroxy-1-methyl-3-(2thiophene)-propyl]-6,14-endo-ethano tetrahydrooripavine), a new analgesic, was in-vestigated in rats. The results of metabolite analysis by liquid chromatography/electrospray ionization tandem mass spectrometry with positive ion mode, in which a mobile phase of 10 mM ammonium acetate (pH 3.0)/acetonitrile (25/75) was used, suggested that thionorphine is biotransformed to two potentially active metabolites, the N-dealkylated thionorphine (M-I) and the oxidized thionorphine (M-II), and subsequently form conjugates with glucuronic acid of both thionorphine and the metabolites.

[Determination of glycosides in traditional Chinese medicine liu-wei di-huang by RP-HPLC].

Objective: To establish a RP-HPLC method for determination of glycosides in Traditional Chinese Medicine Liu-wei Di-huang.

Method: The samples were analyzed on an ODS column at 30 degrees C, with mobile phase of methanol/water (33:67) at flow rate 1.0 mL.

[Identification of the metabolites of penehyclidine hydrochloride raceme in rats by LC-MS/MS and ion cluster].

Aim: To study the metabolites of penehyclidine hydrochloride (PH) raceme, a new anticholinerigic drug invented by the Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences.

Methods: Three healthy rat urine samples were collected within 24 h after a single i.m.