Dear Arun,

The approval of drugs by the US FDA is a time-consuming and expensive process, and approval rates are very low.

You can read this book to learn about the guidelines

title : Nanoparticle Therapeutics: FDA Approval, Clinical Trials, Regulatory Pathways, and Case Study

Biomedical Nanotechnology / Methods in Molecular Biology Volume 726, 2011, pp 325-338

by : Aaron C. Eifler and C. Shad Thaxton

Greetings

Eric

Thank you Mr.Eric

Dear Arun,

You can get more information on the following link

http://www.fda.gov/RegulatoryInformation/Guidances/ucm257698.htm