The vast majority of positive �ndings were synthetic cathi-nones, predominantly α-pyrrolidinopentiophenone (PVP), pentedrone and 3,4-methylendioxypyrrovalerone (MDPV).

EVOLVING ABUSE PATTERNSMethylenedioxypyrrovalerone (MDPV) and methylone were the most commonly found designer stimulants in 2011.

After federal ban of November 2011 abuse patterns have changed: Pentedrone and α-pyrrolidinopentiophenone (PVP), not included in the ban, evolved as the most frequently found cathinones.

Positivity rate sharply declined since September 2012.

THE EXTENT OF DESIGNER CATHINONE METABOLISMSynthetic cathinones with intact or alkylated (R1) aromatic ring appear in urine mainly as β-keto reduced metabolites – substituted ephedrines.

Cathinones with methylenedioxy- attachment to the aromatic ring metabolize by β-keto reduction to a low extent and appear in urine mainly as such.

Pyrrolidinophenones do not convert to alcohols directly. They metabolize by pyrrolidine ring degradation to primary amine, followed by reduction to substituted norephedrines.

INTRODUCTION34,561 urine specimens from various clients were submitted to Redwood Toxicology Labora-tory for designer stimulant testing between February 2011 and January 2012 (2 years).

A large scale study of these specimens provided opportunity to: • assess the magnitude of abuse in tested population • evaluate the prevalence of individual drugs and their change over time • identify major metabolites of new drugs excreted free in human urine and assess their usefulness in routine testing

Designer cathinones (bath salts) and their metabolites were the primary targets in this study.

CONCLUSIONS • Out of total 34,561 urine samples tested, 8% were found positive for designer cathinones, compared to 0.13% positivity for MDMA/MDA/MDEA/MBDB, benzylpiperazine/trifluoromethylphenylpiperazine/ m-chlorphenylpiperazine and p-methoxymetham- phetamine combined.

• Since September 2012 designer cathinone positivity rate declined to 3%.

• Sixteen types of designer cathinones were detected.

• In 2011 methylenedioxypyrovalerone (MDPV) was the most prevalent stimulant, followed by methylone.

• Scheduling of MDPV, mephedrone and methylone in the US led to their replacement by the newer cathinones, primarily by pentedrone and α-pirrolidinopentiophenone (α-PVP).

• Use of metabolites is essential for effective monitoring of a large group of designer cathinones.

Designer Stimulants - Evolving Abuse Patterns Victor Uralets, Sumandeep Rana and Wayne Ross // Redwood Toxicology Laboratory, Santa Rosa, California 95403

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Sample preparation and analysis

Positivity for individual designer stimulants

Monthly positivity by the drug

Variable pro�les of pentedrone metabolites excreted free in human urine

If possible substituted ephedrine metabolites shouldbe synthesized for use as reference material.

GC/MS Chromatogram of a patient sample: multiplecathinones and metabolites are detected.

Stimulants positivity by class—before September 2012

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