title: A rapid cation-exchange HPLC method for detection and quantification of pyridinium oximes in plasma and tissue.
abstract: A rapid and sensitive assay for pyridinium oximes in plasma and tissue was developed. The method was suitable for the analysis of mono- and di-pyridinium oximes and utilizes ultrafiltration followed by cation-exchange high-performance liquid chromatography with UV detection. The assay was originally developed for the measurement of the oxime MMB-4 in plasma for which the lower limit of detection was 0.0005 pg and the limit of quantitation was 0.001 to 2.5 microg. The assay required as little as 50 microL of whole blood or 30 pL of tissue homogenate, and it was used for a pharmacokinetic study from a single intramuscular injection of MMB-4 (dichloride or dimethylsulfonate salt) in the guinea pig. Both salts were found to have similar pharmacokinetic properties in the plasma with a T1/2 of about 34 to 42 min and the area-under-the-curve values increased dose dependently. MMB-4 tissue concentrations were much lower than the plasma. The tissue levels peaked at 5-20 min depending on the tissue. A rank of concentration was diaphragm > heart > thigh muscle.
authors.affiliation: Department of Biochemical Pharmacology, Division of Biochemistry, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, USA.
authors.forename: Harry
authors.initials: H
authors.lastname: Singh
authors.forename: Deborah
authors.initials: D
authors.lastname: Moorad-Doctor
authors.forename: Ruthie H
authors.initials: RH
authors.lastname: Ratcliffe
authors.forename: Katie
authors.initials: K
authors.lastname: Wachtel
authors.forename: Andres
authors.initials: A
authors.lastname: Castillo
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Garcia
mesh_terms: D000818:Animals; D019540:Area Under Curve; D002412:Cations / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002852:Chromatography, Ion Exchange; D004305:Dose-Response Relationship, Drug; D004355:Drug Stability; D006168:Guinea Pigs; D006207:Half-Life; D007273:Injections, Intramuscular; D010091:Oximes / Q000097:blood / Q000493:pharmacokinetics*; D015203:Reproducibility of Results
chemical_list: D002412:Cations; D010091:Oximes; C005514:N,N'-monomethylenebis(pyridiniumaldoxime)