Bioavailability of detomidine administered sublingually to horses as an oromucosal gel.

The research was conducted to understand the absorption, bioavailability, and effects of giving horses detomidine as an oromucosal gel under the tongue, comparing this with injecting the same substance through intravenous and intramuscular means. The study found that less detomidine is absorbed when administered under the tongue than when injected.

Study Design and Methodology

• The experiment employed an open and randomized arrangement, utilizing a three sequences crossover design.
• Nine healthy horses were involved in the experiment.
• Each horse was administered a dose of 40 μg/kg detomidine. The administration was done either intravenously, intramuscularly, or under the tongue.
• The researchers allowed for a 7-day ‘wash-out’ period between each method of drug administration. This prevented the build-up of the substance in the horses’ bodies that could affect the results.
• Blood samples were taken before and after medication for detomidine concentration measures in the serum.

Assessment of Effects and Results

• The impact of the different administration routes on heart rate and rhythm was evaluated.
• The depth of sedation was assessed to determine the effectiveness of the medicine and how much was absorbed in each method.
• The bioavailability of detomidine was found to be 22% (±5.3%) for sublingual administration and 38.2% (±7.9%) for intramuscular administration. This meant that detomidine absorption was lower when administered under the tongue than when injected into the muscle.

Findings and Conclusions

• The study concluded that sublingually administered detomidine partially does not reach the circulation, leading to lower absorption.
• Despite the lower absorption, sublingual administration of detomidine oromucosal gel at a dosage of 40 μg/kg was found to safely sedate horses.
• The slower absorption rate resulting from the sublingual application led to fewer and less severe side effects than the intramuscular injection, which is characterized by quicker absorption.