Simultaneous determination of myristyl nicotinate, nicotinic acid, and nicotinamide in rabbit plasma by liquid chromatography–tandem mass spectrometry using methyl ethyl ketone as a deproteinization solvent

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2005-12, Vol.829 (1), p.123-135
• Main Authors: Catz, Paul, Shinn, Walter, Kapetanovic, Izet M., Kim, Hyuntae, Kim, Moonsun, Jacobson, Elaine L., Jacobson, Myron K., Green, Carol E.
• Format: Article
• Language: English
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Butanones - chemistry; Cancer chemoprevention; Chromatography, Liquid - methods; Fundamental and applied biological sciences. Psychology; General pharmacology; LC–MS/MS; Medical sciences; Myristyl nicotinate; Niacin - analogs & derivatives; Niacin - blood; Niacinamide - blood; Nicotinamide; Nicotinic acid; Pharmacology. Drug treatments; Plasma; Rabbits; Reference Standards; Reproducibility of Results; Sensitivity and Specificity; Solvents - chemistry; Spectrometry, Mass, Electrospray Ionization - methods
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2005.10.003

Myristyl nicotinate (Nia-114) is an ester prodrug being developed for delivery of nicotinic acid (NIC) into the skin for prevention of actinic keratosis and its progression to skin cancer. To facilitate dermal studies of Nia-114, a novel liquid chromatography–tandem mass spectrometry (LC–MS/MS) method using methyl ethyl ketone (MEK) as a deproteinization solvent was developed and validated for the simultaneous determination of Nia-114, NIC, and nicotinamide (NAM) in rabbit plasma. NAM is the principal metabolite of NIC, which is also expected to have chemopreventive properties. The analytes were chromatographically separated using a Spherisorb Cyano column under isocratic conditions, and detected by multiple reaction monitoring (MRM) in positive-ion electrospray ionization mode with a run time of 9 min. The method utilized a plasma sample volume of 0.2 ml and isotope-labeled D 4 forms of each analyte as internal standards. The method was linear over the concentration range of 2–1000, 8–1000, and 75–1000 ng/ml, for Nia-114, NIC, and NAM, respectively. The intra- and inter-day assay accuracy and precision were within ±15% for all analytes at low, medium, and high quality control standard levels. The relatively high value for the lower limit of quantitation (LLOQ) of NAM was demonstrated to be due to the high level of endogenous NAM in the rabbit plasma (about 350 ng/ml). Endogenous levels of NIC and NAM in human, dog, rat, and mouse plasma were also determined, and mean values ranged from