Screening method for the detection of dextromethorphan abuse by hptlc

Dextromethorphan (DXM), the methylated dextrorotatory analogue of a mu-opioid receptor agonist, levorphanol, is a widely available antitussive medicine. At higher levels compared to therapeutic doses, DXM acts as a dissociative hallucinogen and has been shown to be often abused by individuals seeking this particular type of effects. Some reports indicate that DXM causes false positives results in the initial immunoassay urine screening for drugs of abuse. The paper presents a new high performance thin layer chromatographic method (HPTLC) for the determination of DXM in urine samples collected from DXM abusers. The separation has been achieved on chromatographic glass plates precoated with silicagel 60 F254 using as solvent system the mixture methanol: ammonia (100:1.5, v/v). The detection was performed by densitometry in the absorbance mode at 278 nm. An unknown spot, presumably a metabolite of DXM was detected in all urine samples, suggesting that the subjects could be extensive DXM metabolizers. The results indicate that the proposed HPTLC method is a simple and rapid procedure that can be applied as a screening tool for an analytical diagnostic in DXM abuse or intoxication.