Improved enzymatic method for determining mannitol and its application to dog serum after mannitol infusion

Area of Science:

• Biochemistry
• Analytical Chemistry
• Veterinary Medicine

Background:

• Mannitol is a sugar alcohol used therapeutically.
• Accurate quantification of mannitol in biological samples is crucial for clinical monitoring.
• Existing methods may lack specificity or require extensive sample preparation.

Purpose of the Study:

• To develop and validate a novel enzymatic method for mannitol quantitation.
• To assess the method's applicability in determining serum mannitol levels in dogs post-infusion.
• To establish the method's sensitivity, specificity, and linear range.

Main Methods:

• Development of an enzymatic assay utilizing mannitol dehydrogenase and NAD.
• Spectrophotometric measurement of NADH formation to determine reaction rates.
• Application of the assay to canine serum samples following mannitol infusion.

Main Results:

• A linear correlation was observed between initial reaction rates and mannitol concentrations from 17 µmol/l to 6.7 mmol/l.
• The assay accurately reflects serum mannitol levels ranging from 0.5 to 200 mmol/l after appropriate sample dilution.
• The method demonstrated high substrate specificity, unaffected by serum proteins or glucose, though pre-treatment was necessary.

Conclusions:

• The developed enzymatic method provides a reliable and specific means for quantifying mannitol in canine serum.
• This assay is suitable for monitoring therapeutic mannitol levels in veterinary clinical settings.
• The method's specificity and sensitivity make it a valuable tool for pharmacokinetic studies and clinical management.