Transferrin functionalized poloxamer-chitosan nanoparticles of metformin: physicochemical characterization, in-vitro, and Ex-vivo studies.

Object: We report the preparation, characterization, and in-vitro therapeutic evaluation of Metformin-Loaded, Transferrin-Poloxamer-Functionalized Chitosan Nanoparticles (TPMC-NPs) for their repurposing in Alzheimer's disease (AD).

Significance: Usefulness of this work to establish the repurposing of metformin for the treatment of AD.

Methods: The TPMC-NPs were prepared by ionic gelation method using sodium tripolyphosphate. The modification and functionalization were confirmed by FTIR and ¹H^-NMR spectroscopy. The physicochemical characterization was performed using DLS, FTIR,¹H-NMR, CD spectroscopy, SEM, DSC, PXRD, HR-TEM, and hot-stage microscopy.

Results: The size, PDI, percent entrapment efficiency, and percent drug loading of TPMC-NPs were found to be 287.4 ± 9.5, 0.273 ± 0.067, 81.15 ± 7.17%, 11.75%±8.21%, respectively. Electron microscope analysis revealed smooth and spherical morphology. The transferrin conjugation efficiency was found to be 46% by the BCA method. CD spectroscopy confirmed no significant loss of the secondary structure of transferrin after conjugation. PXRD data indicated the amorphous nature of the TPMC-NPs. Hot-stage microscopy and DSC confirmed the thermal stability of TPMC-NPs. The in-vitro drug release showed a sustained release at pH 7.4. The DPPH assay displayed 80% antioxidant activity of TPMC-NPs in comparison with metformin and blank NPs. The in-vitro cytotoxicity assay revealed 69.60% viable SH- SY5Y cells at 100 µg/mL of TPMC NPs. The ex-vivo nasal ciliotoxicity and mucoadhesion studies showed no significant toxicity, and 98.16% adhesion, respectively. The nasal permeability study showed the release of metformin within 30 min from TPMC-NPs.

Conclusion: The obtained results suggested the usefulness of TPMC-NPs in the treatment of AD via the intranasal route.