Incorporation of triclosan into polydioxanone monofilaments and evaluation of the corresponding release

Poly( p ‐dioxanone) monofilaments were loaded with triclosan, a drug with a well‐known antimicrobial effect. Two different procedures were considered: loading by molecular diffusion with a swelling solvent such as dichloromethane and loading by means of a coating based on polycaprolactone or polycaprolactone/magnesium stearate mixtures. Triclosan release was studied in different media by high‐performance liquid chromatography. The kinetics of loading by diffusion and the release from both kinds of preparations were evaluated with well‐established models. In general, the first stages of the loading process fit with the Higuchi approximation, whereas the final stages fit with the first‐order model. The last model could be applied to predict the release behavior. A sustained release over a period that could reach 400 h was attained when ethanol was added to the release medium, whereas equilibrium conditions were reached when Sörensen's hydrophilic medium was used. Significant differences in the release profiles of a Sörensen's/ethanol medium were observed, which depended on the loading methodology. Thus, an 80% release was attained after 36 h for a polycaprolactone‐coated sample and after 80–100 h for a sample loaded by diffusion. Degradation studies of the triclosan‐loaded samples were also performed because the increase in the hydrophobicity of the samples could hinder the hydrolytic degradation. The weight‐average molecular weight of unloaded and loaded (29,075 μg/g) sutures dropped to 220.000 and 110.000 after 45 days of exposure to the medium at 37°C, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009