Implantation of Ketoprofen Into a Biodegradable Suture Using Liquid and Supercritical Carbon Dioxide

Liquid and supercritical carbon dioxide have the ability to swell and plasticize many polymers. Furthermore, the properties of carbon dioxide such as its high diffusivity, low viscosity, environmental friendliness, inertness, and ease of recycling make it an ideal solvent for food and pharmaceutical processing. In this study we explore the use of liquid and supercritical carbon dioxide for the creation of a sustained release drug delivery device. An anti-inflammatory (ketoprofen) is dissolved into carbon dioxide at various temperatures (0 – 55 oC) and pressures (65 – 300 bar) and then exposed to biodegradable suture made of poly(lactide-co-glycolide) copolymers. The effect of temperature, pressure, exposure time and processing conditions are explored on the ability of the substrates to absorb ketoprofen. Uniformity of the absorption is examined by dissolution studies whereby the substrates are exposed to various acid and basic conditions to either slowly or quickly dissolve. The mass transfer of the pharmaceutical out of the substrate is then measured and modeled. Additionally modeling is made of the anti-inflammatory solubility in carbon dioxide as well as the diffusion and mass transfer of the drug into the suture.