Modified QuEChERS-LC-MS/MS Method for Forensic Quantification and Validation of Acyclovir and Amantadine from Biological Matrices

Antiviral drugs exhibit various toxic effects such as teratogenicity, carcinogenicity and surprisingly neurotoxic effects that mimics that of drugs of abuse as indicated by the in silico toxicological studies performed and corroborated with published literature. Despite extensive studies on antiviral drugs, their forensic implications regarding individual toxicity, drug interactions, overdose and abuse have been overlooked. Consequently, there is a critical need to develop an analytical strategy for forensic detection of these antivirals. In this study, a simple and selective LC-MS/MS method is developed to determine toxic antivirals acyclovir and amantadine in urine, saliva and gastric fluid. The modified QuEChERS extraction was followed by chromatography on a C18 column with a gradient mobile phase of 5 mM ammonium formate and 0.1% formic acid in methanol. Detection was performed using a triple quadrupole tandem mass spectrometer. The validation of method, adhering to SWGTOX guidelines, demonstrated excellent linearity, precision and accuracy, covering a linear range of 5-200 ng/mL for both drugs. The limit of detection ranged from 14 to 20 ng/mL and the limit of quantification ranged from 40 to 63 ng/mL for acyclovir and amantadine. Finally, the validated method was successfully applied to the forensic detection of antiviral drugs in gastric lavage, exhibiting robustness and reproducibility.