# Distribution and Blood Penetration of Hirudin in Various Organs and Tissues of Rabbits With Carotid Artery Injury by Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry

## TL;DR

This study tracks hirudin, a medicine from leeches, in rabbits to see how it spreads in the body and blood after artery injury.

## Contribution

The study introduces a reliable UPLC-MS/MS method to analyze hirudin distribution in rabbits with carotid artery injury.

## Key findings

- Hirudin was most concentrated in plasma and blood vessels, followed by spleen, lung, and liver.
- Hirudin levels were lower in brain and heart tissues.
- Control group rabbits had higher hirudin content than the model group.

## Abstract

Background: Hirudin is a major active ingredient of the traditional Chinese medicine leech. It has been proved to have good antithrombotic and anticoagulant effects.

Objective: To determine the tissue distribution of hirudin and its pharmacokinetics in vivo by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Methods: A total of 21 SPF adult New Zealand rabbits were acclimatized for 1 week, and one was randomly selected as a blank control, while the remaining 18 were randomized to the control group and the model group. The heart, liver, spleen, lung, kidney, brain, plasma, blood vessels, and colon tissues were taken by execution at 1, 3, and 6 h. The samples were assayed using the natural hirudin standard as an external standard.

Results: The established UPLC-MS/MS method with good precision, accuracy, recovery, and stability of hirudin proved to be reliable. The correlation between different concentrations of natural hirudin standard and the response value was R2 ≥ 0.9997. The results of the distribution of various tissues showed that hirudin in the two groups had the highest content in plasma and blood vessels, followed by spleen, lung, and liver tissues, and was weaker in the brain and the heart, and the content of hirudin in the control group was higher than that of the model group, and the difference was statistically significant.

Conclusion: The absorption and metabolism of hirudin in rabbits with carotid artery injury mainly acted through vascular tissues and blood, and normal rabbits mainly metabolized it through spleen, lung, and liver.