Preparation and biological evaluation of radioiodinated risperidone and lamotrigine as models for brain imaging

Abstract EN

Brain imaging technology is becoming an important tool in both research and clinical care.

Due to the sensitivity of brain imaging technology, neuroscientists are able to visualize brain structure and function from the level of individual molecules to the whole brain, recognize and diagnose neurological disorders, develop new strategies for treatment and determine how therapies work.

The study aimed to take advantages from drugs that are able to cross the brain barrier for the development of potential radiopharmaceuticals for non-invasive brain imaging.

Risperidone and lamotrigine were successfully labeled with 125I via direct electrophilic substitution reaction at 80oC.

The reaction parameters affecting the preparation process were studied.

125I-risperidone and 125I-lamotrigine gave maximum labeling yield of 89 % ± 3.75 and 97.5 % ± 1.0 %, respectively and their stability were up to 6 and 24 h, respectively.

Biodistribution studies showed that maximum uptake of 125I-risperidone and 125I-lamotrigine in the brain of mice were 4.27 % ± 0.38 and 2.45 % ± 0.18 of the injected activity/g tissue organ, at 10 min post-injection, respectively.

Their clearance was found to be via the hepatobiliary pathway.

Both radioiodinated drugs showed high stability comparing to technetium-99m d, l-hexamethyl propyleneamine oxime (99mTc-HMPAO).

A Further clinical investigation is needed for application of radioiodinated risperidone and lamotrigine diagnostically as positron emission tomography imaging agents.