Time-course of kynurenic acid concentration in mouse serum following the administration of a novel kynurenic acid analog.

The changes in concentration of kynurenic acid (KYNA) in different biological samples are of great interest in the pathomechanism and medication of several disorders, and especially those affecting the nervous system. Besides the recent pharmaceutical advances targeting the kynurenine pathway, there is a constant need for further drug development through the synthesis of novel analogs. Reliable analytical methods should be set up to monitor the metabolism and effects of these analogs in both preclinical experiments and human studies. Following a sample preparation procedure based on protein precipitation, new high-performance liquid chromatographic methods with fluorescence and mass spectrometric detection were developed for the determination of KYNA and a novel KYNA analog (N-(2-N,N-dimethylaminoethyl)-4-oxo-1H-quinoline-2-carboxamide hydrochloride; KYNA amide) in mouse serum samples. The analytical parameters obtained in the validation procedure suggest that the developed method with mass spectrometric detection is simple, fast, accurate and suitable for the measurement of KYNA and its analogs. The results reveal the good in vivo stability of the novel KYNA amide.