Although nanotechnology and nanoscience methods for particle design and formulation are beginning to grow the market for many pharmaceuticals and are laying the groundwork for a lucrative niche within the business, some of the projected benefits have been exaggerated. This paper will discuss logical approaches to the nanoscale vehicle and entity design and surface engineering for site-specific drug delivery and medical imaging following parenteral administration. Nanomaterials help with targeted delivery, prolonged administration, and improved pharmacokinetics profiles, as well as medication diffusion into numerous organs by overcoming barriers such as the blood-brain barrier. Furthermore, these nanoparticles have a higher differential uptake efficiency in target cells (or tissue) compared to normal cells (or tissue) by preventing them from prematurely interacting with the biological environment, improving permeation and retention in disease tissues, and improving cellular uptake, resulting in lower toxicity. In this review, we discuss the most often utilized nanoparticles for increasing medication bioavailability.