MSACL 2019 EU Abstract
Self-Classified Topic Area(s): Small Molecules / Tox / TDM
|
|
 The Effect of Sample Tube Type, pH, Storage Time and Temperature on Antihypertensive Non-Adherence Results by Quantitative LC-MS/MS
A. D. Burns (1), A. Iqbal (1), E. Mulingani (1), D. Lane (1,2), R. Cole (1), P. Patel (1,2), P. Gupta (1,2)
(1)Department of Chemical Pathology and Metabolic Diseases, Leicester Royal Infirmary, Leicester, UK, (2)Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
Warning: Undefined variable $headshot in /var/www/html/view_abstract/view_abstract_in_program.php on line 704
Presenter Bio: I am a biochemistry undergraduate student at Sheffield Hallam University. Currently carrying out a placement year in the Department of Chemical Pathology and Metabolic Medicine at Leicester Royal Infirmary, where I have partaken in research for the National Centre of Drug Adherence Testing (NCAT). Non- adherence to antihypertensive medication has been the main area of my research.
No relevant financial relationship(s) to disclose.
|
|
|
|
|
|
Abstract Background
Hypertension is a global health epidemic, and is the leading cause of disease morbidity and mortality in the world. Non-adherence to hypertension medication is a common problem; around 25% of patients show some degree of non-adherence. Biochemical testing has been developed to diagnose non adherent behaviour. These qualitative screens use liquid chromatography-tandem mass spectrometry (LC-MS/MS), and therefore are the most accurate technique available. However, the effects of pre-analytical factors have been suggested to lead to false negative results. The aim of this study was to investigate the impact of these pre-analytical factors on detection of antihypertensive drugs in urine.
Method
Validation
Six antihypertensive drugs that are currently being used in the non-adherence screen by the National Centre of Drug Adherence Testing (NCAT) were investigated using the Waters Acquity XEVO TQD LCMS system with an ESI Z-spray triple quadrupole mass spectrometer in positive ion mode. A quantification assay for amlodipine, atenolol, indapamide, losartan, propranolol and verapamil, were then validated. Parameters assessed were: precision, accuracy and recovery, linearity, carryover, selectivity, matrix effect, calibration curve, lower limit of detection (LLOD) and lower limit of quantification (LLOQ).
Stability study
Recovery of medications in a sample of six different containers after varying the pH (4-8), temperature (room temperature and 4˚C) and storage time (three or seven days) were studied.
Results
All validation criteria defined by Center for Drug Evaluation and Research (CDER) were met for each of the drugs. Amlodipine, atenolol and verapamil stabilities were most affected by pre-analytical factors. Overall recoveries ranged from 56.1% to 102.2%. The recoveries of all six drugs significantly decreased from pH 4 to pH 8. Stability at room temperature was higher compared to 4˚C. There was a small drop in recoveries of amlodipine, indapamide and verapamil at seven days vs. three days. Glass containers appear to least effect the sample stability while it was the worst with metal cap containers. Universals also had poor recoveries for each of the drugs. LLOD for each drug was below 10ng/mL with CV% <20.
Conclusion & Discussion
Quantitative LC-MS/MS shows there is an effect of pre-analytical factors on levels of antihypertensive medication detected. In particular for pH and sample tube type. Urinary pH is a non-modifiable pre-analytical factor. Sample tube type will need further investigation to assess whether or not it has an effect on the current qualitative biochemical adherence screen for antihypertensives. |
|
| |
= Discovery stage.
= Translation stage.
