Sustained drug release system using porous structured poly(l-lactic acid) fabricated by solvent dispersion method

Abstract

Poly(l-lactic acid) (PLLA) is a synthetic polyester that has been widely used in medicine. However, the degradation of PLLA can be accompanied by an inflammatory reaction, and it is difficult to control the duration of the degradation of PLLA. Thus, a sustained NSAID release porous structured PLLA was fabricated by using a solvent dispersion method. This novel drug release system would provide a consistent release of NSAIDs at a desirable concentration. PLLA and NSAIDs (Sulindac) were dissolved in methylene chloride. After they had homogenously dispersed, the solvent was isolated. Non-porous and porous PLLA substrates mixed with various concentrations (1, 5, and 9 %) of Sulindac were prepared. A morphological examination with a scanning electron microscope was performed. The elution experiment of Sulindac was implemented for 5 days. The drug release and the degradation of the compound in simulated body fluids were examined. No Sulindac particles were identified on the surface of the non-porous compound, however, they were found on that of the porous one. No porosity was found in the cross-section of the non-porous compound. During a 5 day period, the amount of the release of Sulindac was 3.9–17.6 mg/L in the non-porous compound and 21.5–35.1 mg/L in the porous one. In the non-porous compound, the amount of Sulindac released was found to be 3–5 ppm for 20–150 days. In the porous compound, it was found to be 137.7 ppm for 10 days initially. As time elapsed, however, there was a tendency of the release rate to gradually decrease. The authors attempted to prepare a sustained drug release system, which can maintain the concentration of drugs during a longer period in an in vivo setting. This compound could be applied in various ways in the field of material engineering.