**5. Applications of Characterization Techniques on Prediction of NCM Performance**

*5.1. Prediction of Physical and Chemical Stability of NCM*

The success of API delivery to target tissues is largely dependent on the maintenance of stability by the NCM in systemic circulation. The fate of NCM, in vivo, is in part determined by the ability to retain size and payload external to target tissues and to release API to the cells at predetermined rates in appropriate quantities. Ideally, a nanometric drug carrier must remain stable by resisting aggregation or degradation while maintaining API concentrations in the blood until it reaches the target site(s). Altered biodistribution as well as premature drug release can occur as a result of NCM instability, subsequently compromising the performance and efficacy of the delivery system. As such, it is of utmost importance to evaluate NCM with regards to estimating the success of the drug delivery system.

It is important to conduct a series of in vitro tests to investigate the stability of NCM in different biologically relevant media. It is ultimately desirable to conduct investigations into the stability of NCM in vivo since these techniques provide reasonable assessments and prediction of the likely stability of the formulation in physiological environments.
