DETERMINATION OF STEREO-SELECTIVE BINDINGS OF RACEMIC PROPRANOLOL WITH β2-AD-GPCR IN HUMAN PLASMA

Stereo-selective bindings of racemic propranolol with β2-adrenergic G-protein coupled receptor (β2-AD-GPCR) in human plasma were studied by SPE-HPLC and verified by Gold docking software. Experimental results has shown 3.0% more binding of S-(-)-enantiomers in comparison to its R-(+)-antipode. The experimental results ascertained by Gold docking data. The interactions between ligands (propranolol enantiomers) and residues (amino acids of β2-adrenergic receptor sites) were calculated and the stabilities of their stereo-selective complexes were determined. The docking parameters calculated were bond lengths, binding energies, and Gold fitness scores. It has been observed that the stereo-selective fitting of S-(-)-propranolol on β2-AD-GPCR was about three times stronger (SPE-Chiral-HPLC = 3.0%, ES − ER = −0.30 kcal/mol and GFSS-GFSR = 3.31) than R-antipodes. The results presented have confirmed 80–90 time more pharmaceutical potency of S-(-)-propranolol than its R-(+) counterpart. Efforts have also been made to conclude that the unbound amount of R-(+)-enantiomer (3.0%) bind with the precursors of insulin synthesis making cardiac patients diabetic too.