Preparation and Characterization of Phenytoin Sodium Niosomes for Enhanced Closure of Skin Injuries

Objective: Niosomal gel formulations containing phenytoin sodium have been prepared for enhancing skin wound healing. Methods: Solvent evaporation-film hydration methodology was adopted for noisome formation. Different compositions of phenytoin, surfactant and cholesterol were tested. The prepared niosomes were evaluated for size of vesicles, drug entrapment efficiency and release profiles. Results: Niosome micrographs obtained by scanning electron microscopy indicated well-defined and spherically shaped vesicles. Niosomes’s size and zeta potential indicated a smallest average size (74.4 nm), large polydispersity index (0.85) and optimum zeta potential (-58.9 mV) from niosomes containing Span 60 and Pluronic F127 at 1:1 ratio. Niosomes also enabled sustained release of phenytoin sodium from niosomal vesicles which dependedon the type of surfactant used. Formulation F2 containing Span 20 released more than 70 % and 100 % after 14 and 18 hours, respectively. Other formulations containing span 60 alone or mixed with other surfactants sustained the release for more than 24 hours. In-vivo evaluation performed on artificially injured guinea pig skin indicated significant differences (P < 0.05) between healing times for treated group which completely healed within less than 9 days upon using phenytoin sodium niosomal gel formulations compared to placebo gel counterparts which lasted more than 17 days. Conclusion: These findings indicate that niosomes are considered highly effective carriers and skin penetration enhancers for phenytoin sodium. The effects were mainly due to their high content of surfactants and cholesterol combined with collagen proliferation benefits of phenytoin both led to successful and rapid wound healing when employed topically.