Study of the Release Potential of the Antibiotic Gentamicin from Microspheres of BCP

摘要

Orthopedics surgeries frequently are open surgeries, but the improvement of the specific instrumentation and the use of bioresorbable polymerics implants for regeneration of bone fractures are contributing to the development of noninvasive techniques such as an injectable bone substitute. These injectable materials are composites, formed by a particulate ceramic phase and a polymeric phase, and have the advantages of combining bioactivity and the ability to control degradation and some mechanical properties. In addition, microparticles present flexibility to fill several types of defects with closer packing and allow new bone growth and vascularization through the interconnected pores formed by the spaces between them. Another advantage of the particulate materials is that they have the potential to incorporate drugs such as antibiotics that can be applied in situ for treatment or prevention of bone infection, which is important because the poor circulation of blood in the osseous tissues makes necessary large amounts of these drugs to guarantee that an adequate dose reaches the affected site. This work evaluates the release potential of gentamicin from BCP spherical microparticles to be used in osseous injectable implants. The particles present a smooth geometry to prevent inflammatory reactions frequently caused by an irregular morphology, and their compositions offer a combination of biodegradability and stability. Microparticles with diameters between 150-425μm, were obtained by a method based on the immiscibility of liquids. To encapsulate the antibiotic, the spheres were immersed in a gentamicin solution, and after 24h they were separated and dried. The evaluation of the gentamicin release from the microspheres was carried out at 37°C in PBS, and the release medium was collected at predetermined time intervals for measurement of the amount released. This work demonstrates that these microspheres can find potential application in bone repair and regeneration.