Ibuprofen–polymer precipitation using supercritical CO2 at low temperature

• Coprecipitation of spherical microparticles of ibuprofen and polymers has been obtained using SAS process.
• Low temperature supercritical process was used to produce particles composed by ibuprofen and carrier.
• Highest drug/polymer ratio led to less agglomerated particles.
• Not only the polymer nature but also the release fluid influenced release behavior.
• High drug:polymer ratio led to more pronounced burst ibuprofen release.

A process for the SAS coprecipitation of ibuprofen with the polymers poly(l-lactic acid) and Eudragit L100 was successfully carried out. The particle size was reduced to micrometer and near nanometer ranges. The morphology of the raw material changed to spherical upon processing for both poly(l-lactic acid)/ibuprofen particles and eudragit/ibuprofen particles. The eudragit-based particles were significantly smaller than those obtained with poly(l-lactic acid). Ibuprofen release profiles were determined for simulated gastric and intestinal fluids in order to study the effect of the polymer and to identify the appropriate systems for different administration routes. The in vitro release profiles for both polymer/drug systems showed a slower and more controlled release in comparison to the unprocessed ibuprofen. Moreover, the effects of pressure, temperature, initial concentration of the solution and drug-to-polymer ratio on the particle size and morphology of these drug/polymer systems have been evaluated. According to the XRD, DSC and FTIR data, physicochemical interactions do not occur between ibuprofen and the polymers and a proportion of the ibuprofen molecules probably remained on the microparticle surface.

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