Long-term detection of clodronate in equine plasma by liquid chromatography-tandem mass spectrometry.

The research article is about a method that has been developed for detecting a horse medication, clodronate, in the plasma of horses, even for long periods after administration.

Introduction to Topic

• Clodronate is a bisphosphonate drug approved for use in horses but is banned in competition horses due to potential performance enhancing effects.
• There is a need to establish robust methods for detecting the drug in horse blood plasma to enforce this rule and ensure fair competition.

Methodology

• The researchers used chloromethylene diphosphonic acid as an internal standard in plasma samples. This helps in getting reliable and accurate results by comparing the response of the clodronate with the response of the internal standard.
• An automated sample preparation process was developed which included a solid phase extraction with weak anion exchange properties. This helps in isolation and purification of the compounds of interest.
• After the preparation, the residue was treated with trimethyl orthoacetate for methylation, which makes the molecules easier to detect in further steps.
• The sample was then analysed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), a sophisticated technique for separating, detecting, and quantifying compounds.

Results

• The method developed showed good linearity in the range of 1 to 500 ng/ml, indicating reliable measurements at these concentrations.
• The lower limits of detection and quantification were 0.5 and 1 ng/ml respectively, meaning the method can detect even very small amounts of the drug in plasma.
• The precision and accuracy of the method were satisfactory, with less than 15% error suggesting that the method is reliable.
• Verification tests showed the drug did not disappear (no carry-over) and remained stable in plasma even after long-term storage at -20°C, which is critical for long term storage of samples and subsequent reliable detection.
• The method was tested in real-world conditions by successfully detecting clodronate levels in plasma samples from horses treated with an official brand of the drug, Osphos®. This means the method could potentially be used in the official regulation and testing of competition horses.

Next Steps

• The scientists have suggested that the detection method will be verified further in a clinical population study of diseased horses – extending the range of applicability.