Starch-based microspheres produced by emulsion crosslinking with a potential media dependent responsive behavior to be used as drug delivery carriers

This paper describes the development and characterization of starch microspheres for being used as drug delivery carriers in tissue engineering applications. The developed starch microspheres can be further loaded with specific growth factors and immobilized in scaffolds, or administrated separately with scaffolds. Furthermore and due to the processing conditions used, it is expected that these microspheres can be also used to encapsulate living cells. The aim of this study was to evaluate the efficacy of this methodology for further studies with biologically active agents or living cells. The starch microspheres were prepared using an emulsion crosslinking technique at room temperature to allow for the loading of biologically active agents. A preliminary study was performed to evaluate the incorporation of a model drug (nonsteroidal anti-inflammatory drug-NSAID) and investigate its release profile as function of changes in the medium parameters, such as ionic strength and pH. The developed starch-based drug delivery system has shown to be dependent on the ionic strength of the release medium. From preliminary results, the release seems to be pH-dependent due to the drug solubility. It was found that the developed microspheres and the respective processing route are appropriate for further studies. In fact, and based in the processing conditions and characterization, the developed system present a potential for the loading of different growth factors or even living cells on future studies with these systems for improving bone regeneration in tissue engineering, especially because the crosslinking reaction of the microspheres takes place at room temperature.