The field of medicine and healthcare has been greatly influenced by rapid developments when it comes to nanoscience and nanotechnology. This chapter highlights how precise drug administration and diagnostics may be achieved by utilizing nanoscience in drug delivery in the context of nanoscale materials like nanofillers. Drug delivery systems help deliver medicinal drugs and therapeutics effectively to humans. They mostly depend on conventional techniques, including oral, nasal, and other injectable routes. These techniques do, however, have drawbacks, such as ineffective efficacy. It focuses on the important types and functions of nanofillers, including organic, inorganic, graphene, and clay-based fillers, in responsive nanocomposites, considering those that are intended for drug administration in order to overcome these difficulties. Additionally, the contributions they provide to drug encapsulation, stability improvement, and targeted drug administration across a range of therapeutic categories are highlighted. Furthermore, the difficulties and potential benefits of using nanofillers for drug delivery are discussed, along with manufacturing challenges, regulatory issues, safety concerns, and emerging advances in the industry.