Development of an in situ polymeric hydrogel implant of methylprednisolone for spinal injuries
Purpose: To prepare and characterize in situ gel-forming implants of methylprednisolone for the treatment of spinal cord injuries.
Methods: In situ hydrogels of methylprednisolone were prepared by dispersing polylactide glycolic acid (PLGA) polymer and methylprednisolone in N-methyl-pyrrolidone solvent, and subsequent membrane sterilization. Hydrogels were prepared using varying concentrations of PLGA polymer. The physicochemical properties of hydrogels, including visual appearance, clarity, pH, viscosity, drug content, and in vitro drug release, were characterized. In vivo studies were performed to examine antiinflammatory activity (paw edema test) and in vivo motor function activity in a rat spinal injury model after injecting the hydrogels into rats.
Results: The physicochemical properties of the gels were satisfactory. F1, F2, F3, and F4 formulations showed 99.67, 95.29, 88.89 and 88.20 % drug release, respectively, at the end of 7 days. In vivo antiinflammatory activity was highest for F1 (62.85 %). Motor function activity scores (arbitrary scale) for the F1, F2, F3 and F4 formulations were 4.82 ± 0.12, 4.70 ± 0.12, 4.68 ± 0.02, and 4.60 ± 0.05, respectively, and were higher (p < 0.05) for F1, F2 and F3) than for the standard (methylprednisolone, 30 mg/kg body weight, iv; activity score, 4.59 ± 0.20).
Conclusions: The in situ hydrogels of methylprednisolone developed may be useful for the effective management of spinal cord injuries in patients. However, further investigations are required to ascertain their suitability for clinical use.
Keywords: Methylprednisolone, In situ hydrogel, Spinal injury, Motor activity, Implant
Submission of a manuscript to this journal is a representation that the manuscript has not been published previously and is not under consideration for publication elsewhere.
All authors named in each manuscript would be required to sign a form (to be supplied by the Editor) so that they may retain their copyright in the article but to assign to us (the Publishers) and its licensees in perpetuity, in all forms, formats and media (whether known or created in the future) to (i) publish, reproduce, distribute, display and store the contribution, (ii) translate the contribution into other languages, create adaptations, reprints, include within collections and create summaries, extracts and/or abstracts of the contribution, (iii) create any other derivative works(s) based on the contribution, (iv) to exploit all subsidiary rights in the contribution, (v) the inclusion of electronic links from the contribution to third party material where-ever it may be located, and (vi) license any thrid party to do any or all of the above.