Diclofenac release from alginate/carboxymethyl cellulose mono and bilayer films for wound dressing applications

In this study, alginate and carboxymethyl cellulose (CMC) were used to create films to serve as materials for wound dressing applications. These films were obtained by casting as monolayer (ML) and bilayer (BL) structures with and without diclofenac (MLD and BLD, respectively). Morphological characteristics of the films, incorporation efficiency, mechanical properties, water behavior properties, and release kinetics in aqueous media were evaluated. In addition, the mass transfer mechanisms were determined by fitting mathematical models to the experimental data. Bilayer films showed higher diclofenac incorporation efficiency (77.3%) than the monolayer films (57.5%), and both morphological structures were homogeneous and cohesive. The incorporation of diclofenac lowered the mechanical properties of the films without modifying the water absorption capacity. The BLD film had a slower release time (600 min) than the MLD (420 min), thus demonstrating the drug-free layer acts as a barrier to mass transfer and reduces the burst effect. The release from both films was influenced by diffusion; the apparent diffusion coefficients were in the order of 10(-14) m(2) s(-1). MLD had pseudo-Fickian diffusion while BLD had anomalous diffusion. This study demonstrated that the alginate and CMC-based matrices have potential to be used as drug-delivery systems for wound dressing applications.