Rapid determination of recent cocaine use with magnetic particles-based enzyme immunoassays in serum, saliva, and urine fluids

2016-03-08 15:39:03

Journal of Pharmaceutical and Biomedical Analysis; 4 March 2016: DOI:10.1016/j.jpba.2016.03.004

Juan C. Vidala, Juan R. Bertolína, Laura Bonelb, Laura Asturiasc, M.Julia Arcos-Martínezc, Juan R. Castilloa


- Cocaine is one of the most worldwide used illicit drugs.

- This is the first reported mpEIA method for the sensitive determination of cocaine.

- The reported methods are rapid and robust alternatives for cocaine abuse detection.

- Serum, saliva, and urine fluid samples are easily prepared without interferences.

- Unmetabolized COC is of great interest in pharmacologics and toxicologic studies.


Cocaine is one of the most worldwide used illicit drugs. We report a magnetic particles-based enzyme-linked immunoassay (mpEIA) method for the rapid and sensitive determination of cocaine (COC) in saliva, urine and serum samples. Under optimized conditions, the limits of detections were 0.09 ng mL-1 (urine), 0.15 ng mL-1 (saliva), and 0.06 ng mL-1 COC (human serum). Sensitivities were in the range EC50 = 0.6-2.5 ng mL-1 COC. The cross-reactivity with the principal metabolite benzoylecgonine (BZE) was only 1.6%. Recovering percentages of doped samples (0, 10, 50, and 100 ng mL-1 of COC) ranged from about 86 to 111%. Some advantages of the developed mpEIA over conventional ELISA kits are faster incubations, improved reproducibility, and consumption of lower amounts of antibody and enzyme conjugates due to the use of magnetic beads. The reported method was validated following the guidelines on bioanalytical methods of the European Medicines Agency (2011). Unmetabolized COC detection has a great interest in pharmacological, pharmacokinetics, and toxicokinetics studies, and can be used to detect a very recent COC use (1-6 h.).

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Key Words

Cocaine | Magnetic particles-based enzyme immunoassay | Benzoylecgonine | Biological samples | Drugs of abuse | Pharmacokinetics