The analysis of pergolide residues in horse plasma by LC with fluorescence detection.

This study is about the development of a method using liquid chromatography (LC) with fluorescence detection for the detection and quantification of pergolide – a drug used in treating pituitary pars intermedia dysfunction, commonly known as equine Cushing’s Disease, in horses.

Research Objective

• The research aimed to develop a method to detect and quantify pergolide in low concentrations in horse plasma which is often a challenge.
• This was driven by the fact that following the oral administration of pergolide, only low concentrations of the drug are present in horse plasma.
• The researchers also looked at techniques to minimize interference from the matrix and cope with dirty plasma samples and mobile phase buffers that can incapacitate instrumentation.

Methodology and Findings

• The researchers used Liquid Chromatography (LC) in conjunction with fluorescence detection to analyse pergolide residues in horse plasma.
• The lowest limit of quantification (LOQ) for pergolide using this approach was 2 ng/mL with direct injection of horse plasma samples.
• They found that interference from the matrix was minimal, making the method viable for detecting and quantifying minute amounts of pergolide in horse plasma.
• In order to increase the LOQ, the researchers used a process known as Solid Phase Extraction (SPE), which provided cleaner extracts and increased the LOQ to 0.15 ng/mL.
• However, regular replacement of pre-columns was required given the high sample throughput.
• The SPE method was shown to be effective for cleaning and concentrating plasma samples containing pergolide.
• This method was validated using LC-MS/MS against samples from direct injection.

Significance of the Research

• This research provides an effective method for detecting and quantifying pergolide in horse plasma, which is crucial for treating equine Cushing’s Disease.
• Furthermore, the techniques developed in this study also help in maintaining the longevity of analytical instruments, broadening their applicability and usage.
• The SPE method allows for cleaner sample extracts, thus providing more accurate readings of pergolide concentration.