Pathan Gulnaz Nisar Ahmed*
Mohammed Shakir Ghouse
Mir Ashfaq Ali
Muzaffar Ahmed Farooqui
Syeda Saher Naaz
Siddiqui Hajra Yasmeen
Shaikh Mohd Mujtaba
The development of efficacious pharmaceutical formulations is frequently constrained by poor aqueous solubility and limited biopharmaceutical performance of active pharmaceutical ingredients (APIs). It is estimated that more than 40% of newly discovered drug candidates exhibit low water solubility, resulting in suboptimal dissolution, erratic absorption, and reduced oral bioavailability. Among various solubilization strategies, cyclodextrin-based inclusion complexation has emerged as a versatile and clinically validated approach to enhance drug solubility, stability, and therapeutic performance. Cyclodextrins (CDs) are cyclic oligosaccharides composed of α-(1→4)-linked D-glucopyranose units arranged in a truncated cone geometry. The most commonly studied natural cyclodextrins—α-, β-, and γ-cyclodextrin—contain six, seven, and eight glucopyranose units, respectively. Their unique amphiphilic architecture, characterized by a hydrophobic internal cavity and hydrophilic external surface, enables the formation of non-covalent host–guest inclusion complexes with a broad range of hydrophobic molecules. Among them, β-cyclodextrin (β-CD) and its derivatives such as hydroxypropyl-β-cyclodextrin (HP-β-CD) are widely employed in pharmaceutical formulations due to optimal cavity dimensions, favorable safety profiles, and regulatory acceptance. The inclusion process is governed by a combination of hydrophobic interactions, van der Waals forces, hydrogen bonding, and entropic contributions arising from the displacement of structured water molecules within the cyclodextrin cavity. Although thermodynamic parameters such as stability constants and stoichiometry have been extensively studied through phase solubility analysis and spectroscopic techniques, detailed molecular-level understanding of host–guest recognition, binding orientation, and dynamic stability remains incomplete. Such mechanistic insight is essential for rational formulation design, especially when selecting appropriate cyclodextrin derivatives for specific drug candidates. Advances in computational chemistry now allow precise investigation of supramolecular interactions. Molecular docking provides rapid prediction of binding modes and interaction energies, while molecular dynamics (MD) simulations enable time-resolved analysis of conformational flexibility, hydrogen bond persistence, and solvent effects. When integrated with experimental characterization methods—including Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), nuclear magnetic resonance (NMR), and phase solubility studies—a comprehensive mechanistic framework can be established. Despite growing use of computational tools in pharmaceutical sciences, systematic correlation between molecular modeling predictions and experimental validation for cyclodextrin inclusion complexes remains underreported. Most studies focus either on thermodynamic evaluation or computational screening independently, without establishing mechanistic concordance between both approaches.
10.5281/zenodo.19029420