Investigation of Methylene Blue Release from Functional Polymeric Systems Using Dielectric Analysis

Background: Methylene blue (MB) is a photosensitizer used in photodynamic therapy (PDT) to treat colorectal cancer tumors and leishmaniasis infection. The clinical efficacy of PDT using MB is dependent on the physicochemical characteristics of the formulation. Bioadhesive thermoresponsive systems containing poloxamer 407 and Carbopol 934P have been proposed as platforms for PDT. However, the effect of MB on the physicochemical properties of these platforms is not fully understood, particularly in light of the MB availability. Objective: The aim of this study was to investigate the dielectric characteristics of functional polymeric systems containing MB and their influence on mucoadhesion and drug release. Methods: Binary polymeric systems containing different concentrations of poloxamer 407, Carbopol 934P and MB were evaluated as dielectric and mucoadhesive properties, as well as in vitro drug release profile. Results: MB, temperature and polymeric composition influenced the physicochemical properties of the systems. The presence of MB altered the supramolecular structure of the preparations. The mucoadhesive properties of systems were influenced by MB presence and the formulation with the lowest amount of MB displayed faster release. Conclusion: The lower MB concentration in the systems displayed better results in terms of ionic mobility and drug release, and is indicative of a suitable clinical performance.