Abstract
Context: Nanoparticulate systems are new tools that promise a revolution in the field of drug delivery. Among their numerousbenefits, polyelectrolyte complexes (PECs) have shown to provide a barrier to drug release.Objective: In this study, PECs, in the form of self-assembled polymeric nanogels, have been studied as potential drug carriersof the freely soluble drug tramadol HCL trying to achieve a prolonged percutaneous permeation.Methodology: The hydrogels were subjected to swelling, rheology, release and permeation studies and were characterized byFTIR spectroscopy and scanning electron microscopy. Results: P2 hydrogel composed of chitosan-carrageenan (1-1) PEC attainedthe most compromised rheological shear-thinning thixotropic behavior, good bioadhesive properties, the most retardedrelease and permeation with an f2 value <50 compared to chitosan hydrogel, altogether with non-irritancy to the skin. SEMphotographs showed that P2 has spherical nanosized particles structure.Conclusion: This approach can provide us promising results for an around-the-clock analgesia with better safety and tolerabilityprofile.