alpha-Benzyl-N-methylphenethylamine (BNMPA), an impurity of illicit methamphetamine synthesis: pharmacological evaluation and interaction with methamphetamine.

Methamphetamine is a popular drug of abuse, readily synthesized in clandestine laboratories. Illicitly obtained methamphetamine is frequently impure, containing various purposefully added diluents and adulterants, as well as impurities of manufacture and origin. Few impurities have been studied in vivo and limited information exists concerning their pharmacology/toxicology. One such impurity of manufacture is alpha-benzyl-N-methylphenethylamine (BNMPA). Acute toxicity and spontaneous activity (locomotor) studies were conducted with this compound alone and in combination with S(+)-methamphetamine (METH) in male, ICR mice. In the acute toxicity studies, BNMPA was evaluated for convulsant activity. While BNMPA also produced some behavioral disturbances similar to those seen with methamphetamine (e.g., stereotopy) at doses greater than 30 mg/kg, no tonic-clonic convulsions were noted until pre-terminal convulsion at 50 mg/kg. METH alone produced tonic-clonic convulsions at terminal doses of 70 mg/kg. When BNMPA was given in combination with METH, there was no readily apparent change in the convulsion profile from that of METH given alone. In spontaneous activity studies, doses of BNMPA ranging from 1 mg/kg to 50mg/kg failed to alter locomotor activity significantly from controls though 5 mg/kg METH alone significantly increased spontaneous activity. In addition, increases in spontaneous activity elicited by 5 mg/kg METH were not affected when METH was given with 5 mg/kg BNMPA. While BNMPA appears to have toxic effects in the central nervous system (CNS), the failure to affect locomotor activity or alter either METH-induced increases in spontaneous activity or METH-induced convulsions suggests that the two agents are producing their effects through distinct mechanisms.