One Step Preparation of Controlled Drug Release Systems in Supercritical Carbon Dioxide

Abstract

Drug delivery systems based on copolymers of N-isopropylacrylamide were first prepared by a one step method, in which supercritical carbon dioxide was simultaneously used as a polymerization medium and an impregnation agent. The obtained microspheres were characterized by scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The release effect of the in situ prepared microgels impregnated with ibuprofen was presented through in vitro release simulation.

One-pot preparation of thermoresponsive silica-poly(N-isopropylacrylamide) nanocomposite particles in supercritical carbon dioxide

“…Cao et al has reported the values of n and K for poly-(NIPA-co-VP)-Ibu microgels at 37°C are 0.67 and 0.18 at pH 7.4, 1.5 and 0.01 at pH 1.2, respectively. It is demonstrated that the controlled release mechanism of poly(NIPA-co-VP)-Ibu microgels varies from synergism of drug diffusion and framework relaxation to framework relaxation as the pH value changes from 7.4 to 1.2 [40]. The relationship plots between ln(M t /M inf ) and lnt of the PNI-PA-Ibu and SiO 2 -PNIPA-Ibu microgels are shown in Fig.…”