Microcapsules and microspheres: A vision to integral characterization and applications for biotechnological drugs delivery

Microcarriers based on microcapsules and microspheres have been widely studied and tested to control the release of biotechnological drugs (BD), diminishing the dosage or modifying the route of administration. The methods for obtaining microcarriers are complex and varied, so it is necessary to determine the minimum characteristics with which the system must comply. The aim of this work was to establish the main characteristics that should be evaluated in the microcarriers in order to guarantee that the biological activity of biotechnological drugs remains intact through the microencapsulation process, and therefore the safety of the BD (development of immune reactions) remains unaltered. The characteristics of a microcarrier to be evaluated must describe the properties of the material, the size and shape of the system, the particle load, functionalization, the microencap-sulation efficiency, and the kinetics of liberation. Whereas the integrity of BD can be evaluated by critical quality parameter such as: structure and biological function of the BD, product purity, presence of high molecular weight aggregations, higher order structure and biological activity tests. The characterization of the microcarriers must focus on the safety of the bipolymer and proteins tested.