Characteristics of Haloperidol Interacting with Serum Albumins: A Study Using Computational Model

Characteristics of the interaction of haloperidol with HSA and BSA at 25°C and 37°C were studied by applying a computational model based on spectrofluorimetry data. The relative positions of primary binding sites for this drug in albumins were estimated. Haloperidol is a typical or first-generation antipsychotic medication and a neuroleptic drug from the butyrophenone group. Results suggested that the primary binding site for haloperidol in HSA and BSA is located inside the subdomain IB. At 37°C, HPD quenched 12.2(± 0.6)% of HSA fluorescence and 22.7(± 0.9)%  of BSA fluorescence when  [HPD]/[albumin] ratio was 1/1000. For [HPD]/[albumin] ratio equal 2/300, HPD was able to quench 58-65% of fluorescence of the two albumins at 37°C. The association constant of the HSA fluorescence by HPD was found in the order of 107 M-1, approximately two orders of magnitude larger than that found for risperidone, and about three orders of magnitude than those estimated for clorpromazine and sulpiride.