Development of a screening method for the most commonly abused anticholinergic drugs in Jordan; trihexyphenidyl, procyclidine and biperiden.

A sensitive and rapid method for the simultaneous determination of three commonly abused anticholinergic drugs in Jordan; trihexyphenidyl, procyclidine, and biperiden in plasma and urine has been developed using solid phase extraction and GC-MS. Linearity was established from therapeutic to fatal concentrations of the three drugs; 5-300 ng/ml in plasma, with correlation coefficient r(2) > or = 0.9978 and 10-800 ng/ml in urine r(2) > or = 0.9993. Recoveries were in the range of 86-92% and intra-day and inter-day relative standard deviations (n = 6) were in the range of 6.6-10.3% for the three drugs at three different concentrations in plasma and urine. The base peak m/z 98 for trihexyphenidyl, m/z 84 for procyclidine, and m/z 98 and 218 for biperiden, and m/z 339 for papaverine (internal standard) were monitored at selective ion monitoring; their retention times were 8.10, 8.67 and 8.92 min, respectively, and 14.79 min for the internal standard with analysis time of 16.75 min. The limit of detection of 0.5 ng/ml was attained for trihexyphenidyl and procyclidine, while for biperiden 2.0 and 1.0 ng/ml in spiked plasma and urine, respectively. This method has been applied to forensic and authentic samples taken from abuser and patients using these drugs. The method will offer the clinicians and the legal authority the right diagnosis regarding the anticholinergic involved in any case of abuse with less than 1 h per sample (plasma or urine) from the time of receiving.