Abstract
The octanol–water distribution coefficient (logP), used as a measure of lipophilicity, plays a major role in the drug design and discovery processes. While average logP values remain unchanged in approved oral drugs since 1983, current medicinal chemistry trends towards increasingly lipophilic compounds that require adapted
analytical workflows and drug delivery systems. Solubility enhancers like cyclodextrins (CDs), especially 2- hydroxypropyl-β-CD (2-HP-β-CD), have been studied in vitro and in vivo investigating their ADMET (adsorption, distribution, metabolism, excretion and toxicity)-related properties. However, data is scarce regarding the
applicability of CD inclusion complexes (ICs) in vitro compared to pure compounds. In this study, dopamine receptor (DR) ligands were used as a case study, utilizing a combined in silico/in vitro workflow. Mediadependent solubility and IC stoichiometry were investigated using HPLC. NMR was used to observe IC formation-caused chemical shift deviations while in silico approaches utilizing basin hopping global minimization were used to propose putative IC binding modes. A cell-based in vitro homogeneous time-resolved fluorescence (HTRF) assay was used to quantify ligand binding affinity at the DR subtype 2 (D2R). While all ligands showed increased solubility using 2-HP-β-CD, they differed regarding IC stoichiometry and receptor binding affinity. This case study shows that IC-formation was ligand-dependent and sometimes altering in vitro binding. Therefore, IC complex formation can’t be recommended as a general means of improving compound solubility for in vitro studies as they may alter ligand binding.
analytical workflows and drug delivery systems. Solubility enhancers like cyclodextrins (CDs), especially 2- hydroxypropyl-β-CD (2-HP-β-CD), have been studied in vitro and in vivo investigating their ADMET (adsorption, distribution, metabolism, excretion and toxicity)-related properties. However, data is scarce regarding the
applicability of CD inclusion complexes (ICs) in vitro compared to pure compounds. In this study, dopamine receptor (DR) ligands were used as a case study, utilizing a combined in silico/in vitro workflow. Mediadependent solubility and IC stoichiometry were investigated using HPLC. NMR was used to observe IC formation-caused chemical shift deviations while in silico approaches utilizing basin hopping global minimization were used to propose putative IC binding modes. A cell-based in vitro homogeneous time-resolved fluorescence (HTRF) assay was used to quantify ligand binding affinity at the DR subtype 2 (D2R). While all ligands showed increased solubility using 2-HP-β-CD, they differed regarding IC stoichiometry and receptor binding affinity. This case study shows that IC-formation was ligand-dependent and sometimes altering in vitro binding. Therefore, IC complex formation can’t be recommended as a general means of improving compound solubility for in vitro studies as they may alter ligand binding.
Original language | English |
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Article number | 116340 |
Number of pages | 13 |
Journal | Biochemical Pharmacology |
Volume | 226 |
DOIs | |
Publication status | Published - Aug 2024 |
Bibliographical note
Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.Keywords
- 2-hydroxypropyl-β-cyclodextrin
- Inclusion complex
- Dopamine receptor ligands
- In silico
- In vitro
- Semi-empirical quantum chemistry
- Humans
- Protein Binding/physiology
- Solubility
- Receptors, Dopamine/metabolism
- HEK293 Cells
- 2-Hydroxypropyl-beta-cyclodextrin/chemistry
- Ligands
Fields of Science and Technology Classification 2012
- 304 Medical Biotechnology