Tags

Type your tag names separated by a space and hit enter

Reference materials for analytical toxicology including doping control: freeze-dried urine samples.
Analyst. 2004 May; 129(5):449-55.A

Abstract

The feasibility of freeze-dried urine samples containing doping agents to be used in intercomparison exercises and/or as reference materials has been evaluated. Freeze-dried urine samples containing caffeine, ephedrine derivatives (ephedrine, methylephedrine, norephedrine, pseudoephedrine and norpseudoephedrine), amphetamine derivatives (amphetamine, metamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine) and testosterone and epitestosterone glucuronides have been evaluated. For preparation of the samples, blank urines previously subjected to filtration for clarification were fortified with standard solutions of the corresponding compounds and filtered under sterile conditions. Some aliquots of the sterile liquid samples were used for homogeneity testing, others were stored at -80 degree C for reference purposes, and the rest were subjected to lyophilisation. Freeze-dried urine samples were stored at 4-8 degree C and their stability was assessed for a period up to 18 months. Results obtained showed minimal differences (lower than 5%) between lyophilised and non-lyophilised aliquots (stored at -80 degree C) at all time periods except for amphetamine (up to 18%) and norpseudoephedrine (up to 10%). Nevertheless, such differences remained constant over the entire period of study, indicating that the loss of analytes was due to the initial lyophilisation process. The loss of analytes in freeze-dried samples was due to their volatility. Furthermore, an increase in pH by 1 unit was observed following reconstitution of samples prepared from drug-free urine of commercial origin.

Authors+Show Affiliations

Unitat de Farmacologia, Institut Municipal d'Investigacio Medica, Barcelona, Spain.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Evaluation Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15116239

Citation

Jiménez, C, et al. "Reference Materials for Analytical Toxicology Including Doping Control: Freeze-dried Urine Samples." The Analyst, vol. 129, no. 5, 2004, pp. 449-55.
Jiménez C, Ventura R, Williams J, et al. Reference materials for analytical toxicology including doping control: freeze-dried urine samples. Analyst. 2004;129(5):449-55.
Jiménez, C., Ventura, R., Williams, J., Segura, J., & de la Torre, R. (2004). Reference materials for analytical toxicology including doping control: freeze-dried urine samples. The Analyst, 129(5), 449-55.
Jiménez C, et al. Reference Materials for Analytical Toxicology Including Doping Control: Freeze-dried Urine Samples. Analyst. 2004;129(5):449-55. PubMed PMID: 15116239.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Reference materials for analytical toxicology including doping control: freeze-dried urine samples. AU - Jiménez,C, AU - Ventura,R, AU - Williams,J, AU - Segura,J, AU - de la Torre,R, Y1 - 2004/03/22/ PY - 2004/4/30/pubmed PY - 2004/9/21/medline PY - 2004/4/30/entrez SP - 449 EP - 55 JF - The Analyst JO - Analyst VL - 129 IS - 5 N2 - The feasibility of freeze-dried urine samples containing doping agents to be used in intercomparison exercises and/or as reference materials has been evaluated. Freeze-dried urine samples containing caffeine, ephedrine derivatives (ephedrine, methylephedrine, norephedrine, pseudoephedrine and norpseudoephedrine), amphetamine derivatives (amphetamine, metamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine) and testosterone and epitestosterone glucuronides have been evaluated. For preparation of the samples, blank urines previously subjected to filtration for clarification were fortified with standard solutions of the corresponding compounds and filtered under sterile conditions. Some aliquots of the sterile liquid samples were used for homogeneity testing, others were stored at -80 degree C for reference purposes, and the rest were subjected to lyophilisation. Freeze-dried urine samples were stored at 4-8 degree C and their stability was assessed for a period up to 18 months. Results obtained showed minimal differences (lower than 5%) between lyophilised and non-lyophilised aliquots (stored at -80 degree C) at all time periods except for amphetamine (up to 18%) and norpseudoephedrine (up to 10%). Nevertheless, such differences remained constant over the entire period of study, indicating that the loss of analytes was due to the initial lyophilisation process. The loss of analytes in freeze-dried samples was due to their volatility. Furthermore, an increase in pH by 1 unit was observed following reconstitution of samples prepared from drug-free urine of commercial origin. SN - 0003-2654 UR - https://www.unboundmedicine.com/medline/citation/15116239/Reference_materials_for_analytical_toxicology_including_doping_control:_freeze_dried_urine_samples_ L2 - https://doi.org/10.1039/b310111h DB - PRIME DP - Unbound Medicine ER -