Doping control analysis of lithium in horse urine and plasma by inductively coupled plasma mass spectrometry.

The research article discusses a method for detecting abuse of lithium salts in horses by measuring lithium levels in horse urine and plasma using inductively coupled plasma mass spectrometry.

Introduction to Lithium Use in Horses

• Lithium salts, which are often used in treating bipolar disorder in humans, might also be utilized illicitly in horse racing. The potential for misuse arises from lithium’s mood-stabilizing qualities, its low cost, and its easy availability.
• Because lithium can be naturally obtained from soil, plants, and water, equine bodies naturally contain lithium. Therefore, it is essential to establish a misuse threshold for lithium in horses.

Validation of Lithium Detection Method

• The paper presents the validation of methods for quantifying lithium in equine urine and plasma using a technique called inductively coupled plasma mass spectrometry (ICP-MS). This process allows for accurate detection and quantification of lithium levels to identify potential misuse.

Proposed Lithium Threshold in Urine

• After conducting a population study on lithium in horse urine, and an administration study comprising a single oral dose of lithium chloride (to replicate daily lithium intake from a lithium-rich diet), the researchers proposed a urinary threshold for lithium misuse of 5 μg/mL.
• Using this proposed threshold, two additional administration tests were conducted – one involved a single oral dose of 65 g of lithium chloride, and another a single intravenous dose of 2.54 g of lithium chloride. The occurrence of excessive lithium in urine could be detected up to 8 days and 2.5 days after administration, respectively.

Study of Lithium Levels in Plasma

• The researchers also studied the concentrations of lithium in equine plasma following the three lithium chloride administration trials, contributing further data to the understanding of lithium presence and distribution in horses.