Spectrophotometric method development and validation for methamphetamine in human urine

Introduction: Methamphetamine (Meth) is a synthetic stimulant used as main component in many illegal drugs. its abusive use, moreover, can lead to immunodeficiency and neuropsychiatric disorders. Semi-permanent Meth abuse from repeated use from drug resistance and psychological dependence. Aim of work: Work aimed to development of a simple, sensitive and rapid spectrophotometric method for estimation of Meth in human urine. Methodology: The proposed method is based on the formation of an enamine which produced from (addition–condensation reaction) between meth and acetaldehyde then enamine react with sodium nitroprusside to produce an immonium intermediate. The intermediate subsequently reacts with water to form the blue complex. Results: The extraction recovery of Meth was 86.75%. The calibration curves were linear (r2 =1) in from 1 to 100 µg/ml. Limits of detection and quantification were 0.5 and 1 µg /ml respectively. Intra- and inter-assay precision was within 3.21–11.57% and 0.91–2.89% respectively. Intra- and inter-assay accuracy was within 1.68 to 3.75% and 0.69 to 1.15% respectively. Conclusion: Validation for the studied results indicate that the used method for Meth analysis can be successfully applied for its valid determination in screened positive urine for amphetamines.