Synthesis and evaluation of haloperidol ester prodrugs metabolically activated by human carboxylesterase.

Two types of haloperidol prodrugs in which a chemical modification was carried out on the hydroxyl group or carbonyl group were synthesized, and their metabolic activation abilities were evaluated in a human liver microsome (HLM) solution, a human small intestine microsome (HIM) solution and solutions of human recombinant carboxylesterases (hCESs). The metabolic activation rates of alcohol ester prodrugs in HLM solution were similar to those in hCES2 solution, and haloperidol pentanoate and haloperidol hexanoate showed high metabolic activation rates in the synthesized alcohol ester prodrugs. In addition, haloperidol acetate and haloperidol 2-methylbutanoate were hydrolyzed as slowly as haloperidol decanoate.