Development and evaluation of a washing method for the removal of drugs infused on clothing

The presence of drugs, particularly new psychoactive substances (NPS), like synthetic cannabinoid receptor agonists (SCRAs) and novel benzodiazepines, infused in clothes sent to prisons necessitates the development of an effective and non-destructive removal method. The purpose of this study was to devise and assess a laboratory-scale washing method to effectively remove drugs infused in clothing. Small-scale laboratory experiments were performed on different textile types infused with a range of SCRAs commonly encountered within the Scottish Prison estate to test various washing conditions, including temperature, detergent types and concentrations. Large-scale laboratory experiments were performed to extend the applicability of the method to realistic scenarios. The study demonstrates that washing the infused clothes with a minimal amount of detergent currently used by the Scottish Prison Service (4–8 μg/mL) at 40 °C effectively removes up to 98 % of the drug compared to only about 28 % with water alone. Distinctive drug removal percentages were observed among different textile types, with cotton and wool exhibiting the highest drug removal percentage and polyamide and cotton-elastane the least. Drug transfer from infused to blank textiles was limited, with only a small fraction of the initial amount retained. The implications of this method can be applied to prisons worldwide, effectively mitigating drug-related issues and ensuring the safety of both prisoners and prison staff. • Detergent use in washing improves removal of drugs from infused textiles. • Natural fibres show lower drug retention than synthetic fibres. • Scale-up washing experiments indicate feasibility for prison laundry services.