Assessing the structural, antibacterial, and dissolution properties of 1:1 doxycycline/β-cyclodextrin complexes

• Published in: Journal of molecular structure Vol. 1321; p. 139977
• Main Authors: Shwetha, JC, Pruthviraj, K, Rao, T Bhaskara, Solomon K, Anand
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.02.2025
• Subjects: Antibacterial activity; Coprecipitation; Dissolution study; Doxycycline; Kneading method; Antibacterial activity; Dissolution study; Kneading method; Coprecipitation; Doxycycline
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.139977

•Doxycycline/beta-cyclodextrin complexes improved drug solubility via kneading & coprecipitation (CPT) methods.•CPT is most effective for enhanced dissolution based on characterization techniques.•Both KND & CPT complexes showed improved antibacterial activity against various strains.•This suggests CPT is a better approach for formulating DO with superior therapeutic potential. A 1:1 β-cyclodextrin (βCD) inclusion complex with doxycycline (DO) as the guest molecule was prepared using kneading (KN) and coprecipitation (CoP) methods, along with a physical mixture (PM) . The complex was characterized through FTIR, ¹H NMR, UV–Vis spectroscopy, and DSC analysis. Semi-empirical quantum mechanical calculations confirmed the inclusion of DO within βCD's hydrophobic cavity. The formation constant, determined by a modified Benesi-Hildebrand equation at 25 °C, was 116.22 M⁻¹ for the βCD-DO complex. Dissolution studies revealed that the CoP method significantly enhanced DO's dissolution kinetics compared to the KN, PM methods, and free DO, highlighting CoP's effectiveness. Molecular docking indicated a stable βCD-DO complex, with binding energies from -5.9570 to -6.1423 kcal/mol, driven by hydrophilic and hydrophobic interactions. Antibacterial testing against E. coli, P. aeruginosa, S. aureus, B. cereus, and B. subtilis showed CoP had the highest efficacy, with MIC values of 5–10 µg/ml and MBC values of 10–20 µg/ml, better than KN, DO, and βCD. [Display omitted]