Brotizolam radioimmunoassay: development, evaluation, and application to human plasma samples

Area of Science:

• Pharmacology
• Analytical Chemistry

Background:

• Brotizolam is a hypnotic agent requiring precise quantification in biological samples.
• Existing methods may lack specificity or sensitivity for brotizolam and its metabolites.

Purpose of the Study:

• To develop and validate a sensitive and specific radioimmunoassay (RIA) for determining brotizolam concentrations in human plasma.
• To assess the stability of brotizolam in plasma under frozen conditions.

Main Methods:

• Development of a radioimmunoassay using an antiserum against a brotizolam analogue (hapten 10) and tritium-labeled brotizolam.
• Validation of the assay for sensitivity, accuracy, and precision using plasma samples.
• Application of the assay to measure brotizolam plasma levels in subjects after oral administration.

Main Results:

• The developed RIA demonstrated high specificity against brotizolam metabolites.
• The assay sensitivity limit was approximately 100 pg/mL with high accuracy and precision.
• Brotizolam plasma concentrations showed a mean maximum of 4.6 ng/mL at 0.9 h, with a mean elimination half-life of 5.1 h.

Conclusions:

• The developed radioimmunoassay is a reliable method for quantifying brotizolam in plasma.
• The assay's specificity and sensitivity are suitable for pharmacokinetic studies.
• Brotizolam is stable in frozen plasma samples, and its pharmacokinetic profile was accurately determined.