Development of a Novel Niosomal Formulation for Gabapentin

Gabapentin is an anticonvulsant drug prescribed to treat partial seizures and neuropathic pain. Niosomes, as lipid-based drug carriers, can improve the pharmacokinetic properties of therapeutic agents. In this study, we developed an optimal niosomal formulation for gabapentin and assessed its cytotoxicity effect on normal cells and a colon cancer cell line. Methods: Several niosomal formulations were developed and analyzed regarding physicochemical properties. For the G3 and G4 formulations, the release profiles complied much better with the Korsmeyer-Peppas model, suggesting the Fickian diffusion mechanism in gabapentin release. The effect of the optimized niosomal formulation of gabapentin on the SW48 colon cancer cell line was assessed using the MTT assay. Results: The niosomal formulation of G3 showed 60% drug release in 48 hours, and the G4 formulation showed 52%. The cytotoxic effect of the optimized formulation (G3) on the colon cancer cell line resulted in an IC50 of 45 μg/ml (200 μM) after 48 h, compared to 0.2 mg/mL (1.17 mM) for free gabapentin. Hence, the niosomal formulation of gabapentin was more cytotoxic for the colon cancer cell line than pure gabapentin. Conclusion: The optimal niosomal formulation of gabapentin exhibited good storage stability and provided slow, prolonged release. This formulation showed cytotoxic effects on colon cancer cells without significant toxicity for normal fibroblasts.