Novel Functional Nano-size Nonionic Surfactant Particles on Which Cationic Metalloporphyrins are Absorbed; Preparation, Characterization, and Anti-oxidant Properties

Cationic manganese (III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl) porphyrin (MnT2MPyP) and manganese (III) 5,10,15,20-tetrakis(N-methylpyridinium-4-yl) porphyrin (MnT4MPyP) complexes were synthesized as superoxide dismutase (SOD) mimics which were introduced into niosomes so as to examine this effects on the capacity of drug delivery system (DDS) to maintain and perpetuate blood circulation. All the niosomes were prepared from polyoxyethylene solbitan monostearate (Tween 61) by the conventional sonication method. SOD activity was measured by the stopped-flow analysis and the cytochrome c method. Sodium stearate-linked MnT2MPyP was found to be the most effective catalyst along with SOD activity for decomposing O₂^- • at a second-order rate constant of 2.0 × 10⁷ M^-1s^-1 in Tween 61 niosomes. Rate constants of metalloporphyrin-embedded niosomes for reaction with hydrogen peroxide (H₂O₂) and half-life times in H₂O₂ were also determined. Metalloporphyrin-embedded niosomes were found to have greater half-life times compared to metalloporphyrin without niosomes. The present findings clearly indicate that metalloporphyrin-embedded niosomes are highly effective for bringing about O₂^-• decomposition and should thus find application as DDS in antioxidant drugs.