Determination of the unstable drug otilonium bromide in human plasma by LC–ESI-MS and its application to a pharmacokinetic study

Exploring the Antimicrobial Action of Quaternary Amines against Acinetobacter baumannii

“…Since QACs are frequently more effective against Gram-positive bacteria ( 6 ), we also tested Staphylococcus aureus and Clostridium difficile . Due to the instability of otilonium bromide ( 44 ), we measured the activity of these compounds by a minimal bactericidal concentration (MBC) assay ( 45 ) ( Table 3 ). Bretylium tosylate showed no effect against any strain.…”

Development, validation and application of the liquid chromatography tandem mass spectrometry method for simultaneous quantification of azilsartan medoxomil (TAK-491), azilsartan (TAK-536), and its 2 metabolites in human plasma

“…Especially, ester-based prodrugs are inherently unstable in biological fluids because hydrolytic enzymes such as esterases are widely distributed throughout the body in humans and animals [6]. To prevent the degradation of ester-based prodrugs in blood, serum or plasma, there have been several approaches reported previously such as the addition of esterase inhibitors or organic solvents, pH adjustment, temperature control of the samples, using EDTA as an anticoagulant and implementation of a dried blood spotting technique [5,[7][8][9][10][11][12][13][14][15]. These approaches are often employed in combination depending on the analyte characteristics and operational conditions, and in most cases, some esterase inhibitors have been added to blood or plasma samples to inactivate the esterases.…”