Among drug delivery systems, polymer microspheres have been proved to be the most promising carriers during the past several years. In this paper we describe the preparation of poly(L-lactide-co-glycolide-co-ε-caprolactone) (PLLGC) random terpolymer microspheres; their in-vitro degradation behaviors, including the changes of pH value, mass loss, molecular mass and surface morphology, were investigated during various degradation periods and compared with poly(lactic-co-glycolic acid) (PLGA) microspheres. The results showed that the introduction of the ε-caprolactone (ε-CL) unit reduced the degradation rate of the PLGA polymers. Therefore, we suggest the PLLGC microspheres with controllable degradation rate could supply a wider application future in drug delivery field than pure PLGA microspheres.
The technique of thermally induced phase separation (TIPS) is favorable for the fabrication of a porous scaffold due to a number of advantages. In this work the poly(L-lactide-co-glycolide-co-ε-caprolactone) (PLLGC) terpolymer was synthesized by melt copolymerization and porous scaffolds thereof from its solution in 1,4-dioxane were fabricated by using the TIPS method. The effects of fabrication parameters, including polymer concentration and freezing temperature, on the morphology, pore size and mechanical properties were studied. The results showed that the average pore size of the PLLGC porous scaffold increased with a decrease in PLLGC concentration and the pore size resulting from freezing at 4 °C (about 20–100 μm) was significantly larger than for other samples (20–50 μm) frozen at lower temperatures. The porosity of the scaffolds decreased with increasing PLLGC concentration or decreasing freezing temperature. On the other hand, the compressive strength of the scaffolds increased with the increase of PLLGC concentration or the decrease of freezing temperature, as would be expected. The present results can be applied in design to control the processing parameters of TIPS for a scaffold with desired pore morphology.
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