Synthetic cathinones are drugs of abuse substituted for amphetamine-like stimulant drugs such as methamphetamine. In this study, methamphetamine was studied as a prototypical amphetamine-like drug as a first step toward establishing methods to study this entire drug class. The internal concentration of methamphetamine in zebrafish larvae was determined using matrix-matched calibration along with extraction and purification of samples using the quick, easy, cheap, effective, rugged, and safe technique in liquid chromatography-tandem mass spectrometry. Whole-body and head/trunk uptake and elimination in 5-day postfertilization zebrafish larvae were determined. A gradient method was developed using 5 mM ammonium formate with 0.1% formic acid and methanol with 0.1% formic acid as mobile phases, 10 min of total run time, and a 0.3 mL/min flow rate. The limit of quantification was 60 ng/mL, linearity with r2 = 0.9991, and recovery values from 92% to 120%. The internal concentration of methamphetamine was quantifiable in whole-body homogenates within 15 min of uptake analysis. The internal concentration increased with time, whereas a biphasic elimination pattern was shown. With increasing length of exposure, a higher accumulation of drugs was found in the head than in the trunk.
Keywords: cathinone; liquid chromatography; methamphetamine; pharmacokinetic; zebrafish.