The question is from a very broad perspective. To give a precise answer to this, it depends purely on the method of nanoparticle synthesis primarily. Suppose you opt for chemical method of synthesis which involves lot of thermal treatment including reflux, calcinations etc., incorporating a drug during the synthesis procedure might alter the properties of both the desired outcome of the nanoparticle to be synthesized and also the drug which might lose its inherent properties due to the above said treatments.
So I would suggest its better to synthesize the desired nanoparticle in the appropriate procedure and then incorporate the drug in a desired environment and technique where the drug remains stable and does the task its meant to do.
Alternatively, if the synthesis procedure occurs at room temperature and it doesn't change the properties of the drug when incorporated, the combining both could also be an option. All the best for your research.
Dear all, for each type of nanocarrier there are various possibilities of drug encapsulation. The following attached chapter gives a brief review of some nanocarriers and the encapsulation methods. My Regards