title: Interaction between Eudragit® E100 and anionic drugs: addition of anionic polyelectrolytes and their influence on drug release performance.
abstract: In this work, we report results concerning the study of solid complexes compounded by a cationic polymethacrylate (Eudragit® E100, Eu) and mesalazine (M) (Eu-M(x) complex). The influence of an anionic polyacrylic acid polymer (carbomer, C) on dissolution behavior of M from the complex was evaluated (Eu-M(x) C(y) complex). The dissolution profiles and solvent front movements of solid matrices in different media (water, buffer pH 7.4, 0.9% NaCl) were investigated and ionic interactions among Eu, M, and C were determined through Fourier transform infrared (FT-IR) spectroscopy. For Eu-M(x) complexes, the affinity between M and Eu modulated the delivery of free M in solution, with the dissolution media affecting the delivery rate mainly due to an ionic interchange process between M and anionic electrolytes (i.e., Cl(-)). FTIR spectroscopy allowed the ionic interaction between Eu and M to be verified. The addition of C (Eu-M(x) C(y) ) influenced the dissolution behavior of these matrices. As the amount of C was increased, the release mechanism changed from diffusion (Eu-M(50) ) or anomalous (Eu-M(100)) to zero order (Eu-M(x) C(50)). This variation in rate delivery was also affected by the dissolution media, as occurred with Eu-M(x) complexes. The formation of the gel layer during the dissolution process, as consequence of Eu-M(x) C(y) matrices hydration, was influenced by C amount and dissolution media.
authors.affiliation: Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina.
authors.forename: Daniela A
authors.initials: DA
authors.lastname: Quinteros
authors.forename: Ruben H
authors.initials: RH
authors.lastname: Manzo
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Allemandi
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D000838:Anions; D004573:Electrolytes / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D010599:Pharmacokinetics; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000179:Acrylates; D000838:Anions; D004573:Electrolytes; C477020:Eudragit E100; D004364:Pharmaceutical Preparations; D011108:Polymers