Well, the good news is that it's easy to find information on this topic. The bad news is that it's almost too easy to find information on this topic. It's such an active area that finding the best reviews and summaries of the field can be a daunting task. It's almost too big to review in a single article (but too fast-moving to make a textbook useful), so most of the reviews you'll find have a narrower scope than just "nanoparticles for drug delivery". Even this search string in SciFinder turns up thousands of hits for reviews. There are whole journals dedicated to drug delivery, much of which is by nanoparticle, including: Journal of Controlled Release, International Journal of Nanomedicine, Advanced Drug Delivery Reviews, Nanomedicine, Critical Reviews in Therapeutic Drug Carrier Systems.
I haven't been actively involved in this field for a few years, so most of my personal library is out of date. I did a brief search of the literature and here are a few promising general introductions to the topic published within the last year or two. The ones with asterixes are ACS Nano perspective articles, which might be especially useful to you. These are sort of brief state-of-the-science commentaries - a good place for a new investigator to start delving into it.
Choi, HS. Nanoparticle assembly building blocks for tumor delivery. Nature Nanotechnology (2014), 9(2), 93-94.
Li, C. A targeted approach to cancer imaging and therapy. Nature Materials (2014), 13(2), 110-115.
Ma, L.; Kohli, M.; Smith, A. Nanoparticles for Combination Drug Therapy. ACS Nano (2013), 7(11), 9518-9525.
Mura, S.; Nicolas, J.; Couvreur, P. Stimuli-responsive nanocarriers for drug delivery. Nature Materials (2013), 12(11), 991-1003.
* Park, K. Facing the Truth about Nanotechnology in Drug Delivery. ACS Nano, 2013, 7 (9), pp 7442–7447.
* Barry, N. P. E.; Sadler, P. J. Challenges for Metals in Medicine: How Nanotechnology May Help To Shape the Future. ACS Nano (2013), 7(7), 5654-5659.