Sensitive quantification of 5F-PB-22 and its three metabolites 5F-PB-22 3-carboxyindole, B-22 N-5-hydroxypentyl and PB-22 N-pentanoic acid in authentic urine specimens obtained from four individuals by liquid chromatography–tandem mass spectrometry

Abstract

Urine is the most suitable specimen to collect from individuals because of noninvasiveness and relatively large volumes obtainable. In authentic urine specimens, however, synthetic cannabinoids having the structures of quinolinyl ester indoles, such as 5F-PB-22, PB-22 and BB-22, in unchanged forms as well as their metabolites, have not been quantified yet. Therefore, the aim of this study was to establish a sensitive analytical method for the quantification of 5F-PB-22 and its three metabolites 5F-PB-22 3-carboxyindole, PB-22 N-5-hydroxypentyl and PB-22 N-pentanoic acid in authentic urine samples in four cases. These compounds were extracted from β-glucuronide-hydrolyzed and unhydrolyzed urine via liquid-liquid extraction. The identification and quantification were performed using the QTRAP type of a liquid chromatography–tandem mass spectrometer. The limits of detection were 3–30 pg/mL and their summed quantitation range was 10–10,000 pg/mL. The devised method was applied to quantify these compounds in authentic urine specimens obtained from four individuals. The levels of 5F-PB-22 were 5.1, 13.6, 94.7 and 470 pg/mL; those of 5F-PB-22 3-carboxyindole were 8.25, 3.39, 23.2 and 880 ng/mL; and those of PB-22 N-pentanoic acid were 12.0, 57.4, 959 and 2090 pg/mL, respectively, in four unhydrolyzed urine samples, and the levels of PB-22 N-5-hydroxypentyl could be quantified as 29.9 and 131 pg/mL in two unhydrolyzed urine samples. The 5F-PB-22 and its metabolites PB-22 N-5-hydroxypentyl have been detected from authentic human urine samples for the first time. Also, this is the first report dealing with the quantification of the three metabolites in human urine samples.