Estimation of ZYKR1 in human urine and plasma utilizing LC-MS/MS positive electrospray ionization; a kappa opioid receptor (KOR) agonist.

ZYKR1, a short chain novel peptide with selective kappa opioid receptor agonist activity used as analgesics for the treatment of pain management. A sensitive and selective LC-MS/MS assay was developed and validated for estimation of ZYKR1 in human urine and plasma. ZY17258, an analogue compound was used as an internal standard.

Comparative Pharmacokinetics of Cholecalciferol in Dogs from 2 Different Oral Formulations Using Corrective Measures to Overcome Interference from Endogenous Cholecalciferol.

The aim of the preclinical investigation was to obtain single dose pharmacokinetics in dogs from 2 different oral cholecalciferol formulations using corrective measures to overcome the interference of endogenous cholecalciferol. 6 dogs were fasted overnight and the following day received 60 000 IU dose cholecalciferol [reference, Eris, vs. test, Sunbless] by oral dosing.

A sensitive quantitative assay for the determination of propafenone and two metabolites, 5-hydroxypropafenone and N-depropylpropafenone, in human K2EDTA plasma using LC-MS/MS with ESI operated in positive mode.

Propafenone is a potent antiarrhythmic agent; clinically propafenone has been used for a number of cardiac arrhythmias because it possesses multiple modes of action, via beta adrenergic receptor blockade and calcium antagonistic activity. Propafenone (PPF) exhibits extensive saturable presystemic biotransformation (first-pass effect) resulting in two active metabolites: 5-hydroxypropafenone (5-OH PPF) formed by CYP2D6 and N-depropylpropafenone (NDP) formed by both CYP3A4 and CYP1A2 enzymes. A specific and sensitive LC-MS/MS method was developed and validated for quantitation of PPF, 5-OH PPF and NDP using turboion spray in a positive ion mode.

An LC-MS/MS assay for the quantitative determination of 2-pyridyl acetic acid, a major metabolite and key surrogate for betahistine, using low-volume human K EDTA plasma.

Betahistine is widely used for the treatment of vertigo. Owing to first-pass metabolism, 2-pyridyl acetic acid (2PAA, major metabolite of betahistine) was considered as surrogate for quantitation. A specific and sensitive LC-MS/MS method was developed and validated for quantitation of 2PAA using turbo-ion spray in a positive ion mode.

Quantitative determination of saroglitazar, a predominantly PPAR alpha agonist, in human plasma by a LC-MS/MS method utilizing electrospray ionization in a positive mode.

A sensitive LC-MS/MS method was developed and validated for quantitation of saroglitazar using turboion spray interface with positive ion mode. A liquid-liquid extraction, with a mixture of dichloromethane and diethyl ether, was employed for the extraction of saroglitazar and glimepiride (IS) from human plasma. The chromatographic separation was achieved using an ACE-5, C (4.