DFT studies for searching of anti-microbial excipients for the novel formulation of clindamycin

Pharmaceutical excipients serve vital roles in drug formulations as preservatives, coloring agents, lubricants, binders, disintegrates, and diluents. Clindamycin, lincosamide antibiotic, is widely used to treat various bacterial infections, including osteomyelitis joint infections, pelvic inflammatory disease, strep throat, pneumonia, acute otitis media, and endocarditis. It is available in multiple dosage forms such as oral, intravenous, topical, and vaginal formulations. Among common preservatives, benzyl alcohol is frequently used in clindamycin formulations. Density Functional Theory (DFT) has been employed to investigate the physical and chemical stability of clindamycin in the presence of three preservative excipients: phenol, benzyl alcohol, and o-phenyl phenol. Molecular interactions have been analysed using calculated binding energies, molecular electrostatic potential (MESP) maps, and topological parameters. Chemical stability has been further evaluated through simulated infrared (IR) spectra. The DFT-based computational approach enabled the comparative assessment of excipient-drug interactions to identify the most suitable preservative excipient for clindamycin formulation.