A Simple and Effective Physical Characteristic Profiling Method for Methamphetamine Tablet Seized in China

Methamphetamine ( MA ) tablet production confers chemical and physical properties. This study developed a simple and effective physical characteristic profiling method for MA tablets with capital letter “ WY ” logos, which realized the discrimination between linked and unlinked seizures. Seventeen signature distances extracted from the “ WY ” logo were explored as factors for multivariate analysis and demonstrated to be effective to represent the features of tablets in the drug intelligence perspective. Receiver operating characteristic ( ROC ) curve was used to evaluate efficiency of different pretreatments and distance/correlation metrics, while “Standardization + Euclidean” and “Logarithm + Euclidean” algorithms outperformed the rest. Finally, hierarchical cluster analysis ( HCA ) was applied to the data set of 200 MA tablet seizures randomly selected from cases all around China in 2015, and 76% of them were classified into a group named after “ WY ‐001.” Moreover, the “ WY ‐001” tablets occupied 51–80% tablet seizures from 2011 to 2015 in China, indicating the existence of a huge clandestine factory incessantly manufacturing MA tablets.