Gabapentin in horses: validation of an analytical method for gabapentin quantitation.

This study focuses on developing and validating a method to quantify the levels of the drug gabapentin in horses using gas chromatographic-mass spectrometric (GC-MS) technique. With a tendency for performance-enhancing use in race horses, this method can provide accurate measurements that help in pharmacokinetic studies and preventing unfair practices in horse racing.

Objective of the Study

• The primary objective of this study is to create an effective and reliable method for detecting and measuring the amount of the anticonvulsant medication, gabapentin, in horses.
• Given that gabapentin is categorized by the Association of Racing Commissioners International as a potential performance-enhancing substance, the accurate detection of its levels is essential to prevent its misuse in competitive horse racing environments.

Methodology

• The researchers incorporated a gas chromatographic-mass spectrometric (GC-MS) method for gabapentin detection.
• GABA-d(2) (Gamma-aminobutyric acid-d(2)) was used as an internal standard during the solid-phase extraction process. Unlike gabapentin, GABA-d(2) mostly does not form a lactam structure, which makes it an efficient contrast in this detection process.
• To assure that gabapentin was correctly identified, the researchers utilized electrospray-ionization mass spectrometry. This method was used to confirm that a compound matching the expected molecular weight of gabapentin (171 m.w.) was indeed present.
• The overall extraction efficiency of the proposed assay was measured at around 60%.

Results and Conclusion

• A standard curve was created, ranging from 50 ng/mL to 3000 ng/mL, which provided accurate within-run and between-run variations and accuracies at low, medium, and high concentrations.
• The limit of detection, defined as the mean response at zero concentration plus twice the standard deviation, was calculated to be around 7.6 ng/mL.
• The limit of quantitation, which represents the lowest concentration that can be determined with acceptable precision and accuracy, was calculated at nearly 17 ng/mL.
• Overall, this method shows promise in accurately quantifying gabapentin in equine biological fluids, serving as an efficient tool for both pharmacokinetic and forensic studies.