most of the research around CR formulations has been focused on implementing nanoparticles to decrease the rate of drug clearance. Modulated drug release and zero-order drug release Many scientists worked to create oral formulations that could maintain a constant drug level because of the ability of drug release at a zero-order rate.blood's concentration. However, a few physiological restrictions made it challenging to create such oral formulations. First, because the lower parts of the intestine have a decreased capacity for absorption, the medication absorption typically declines as an oral formulation moves from the stomach to the intestine. The decreased drug amount released from the formulation over time frequently made this condition worse. Phenylpropanolamine HCl release from was the only instance of sustaining consistent blood concentration for roughly 16 hours. Delivery of biologic drugs Pharmaceutical preparations containing peptides, proteins, antibodies, genes, or other biologic components often face absorption issues due to their large sizes or electrostatic charges, and may be susceptible to enzymatic degradation once they have entered the body. For these reasons, recent efforts in drug delivery have been focused on methods to avoid these issues through the use of liposomes, nanoparticles, fusion proteins, protein-cage nanoparticles, exploiting routes for the delivery of biologicals that toxins use and many others. Intracellular delivery of macromolecules by chemical carriers is most advanced for RNA, as known from RNA-based COVID-19 vaccines, while proteins have also been delivered into cells in vivo and DNA is routinely delivered in vitro. One of the applications of drug delivery system by using nanoparticles Drug delivery systems have been around for many years, but there are a few recent applications of drug delivery that warrant 1. Drug delivery to the brain: Many drugs can be harmful when administered systemically; the brain is very sensitive to medications and can easily cause damage if a drug is administered directly into the bloodstream. As new drug formulations are being developed for brain diseases, including Alzheimer’s disease and Parkinson’s disease, researchers are working on ways to deliver drugs into the brain that do not cause damage to healthy tissue. For example, scientists have developed nanoparticles that can cross the protective blood-brain barrier and deliver drugs directly to the brain. See also Acoustic targeted drug delivery Asymmetric membrane capsule Bioavailability Bovine submaxillary mucin coatings Chemotactic drug-targeting Drug delivery to the brain Drug carrier Magnetic drug delivery Neural drug delivery systems Retrometabolic drug design Self-microemulsifying drug