CONTROLLED AND SUSTAINED RELEASE DRUG DELIVERY TECHNOLOGIES

The limitations of traditional dosage forms led to the development of two improved drug delivery technologies: sustained release (SR) and controlled release (CR). Conventional immediate formulations typically lead to a fast rate of drug absorption and consequent rapid drops in plasma concentrations, which increases the likelihood of adverse effects, frequent dosage, and poor patient compliance. The purpose of controlled and sustained release systems is to keep the drug concentration in the therapeutic range over a long period of time by controlling the rate and pattern of drug release. The sustained release systems lengthen the period in which the drug takes action by retarding drug release whilst the controlled release system delivers the drug in a steady rate which is pre-programmed and predictable without physiological factors. Diffusion, dissolution, osmosis, swelling, erosion, and ion exchange are the fundamental principles that underpin these technologies. For CR and SR formulations to be successful, substantial consideration must be given to drug physicochemical features, pharmacokinetics, biological variables, and polymer characteristics. The medication release rate can be altered using a wide variety of polymers, including natural, semi-synthetic, and synthetic ones. Matrix systems, reservoir systems, multiparticulate systems, and microencapsulation techniques are some of the formulation methodologies that can be used. The manufacturing processes of wet granulation, direct compression, coating, and hot melt extrusion are highly successful in producing consistent and efficient release profiles. In-vitro dissolution studies, in-vivo performance testing, and in-vitro-in-vivo correlation (IVIVC) can all be used to assess these systems. Reduced dose schedules, patient compliance, bioavailability, and fewer side effects are advantages of controlled and sustained release drug delivery systems. However, there are challenges with gastrointestinal fluctuation, dosage dumping, and complex manufacturing processes. With the ongoing advancements in polymer science and formulation technology, the breadth of controlled release systems is expanding, and CRS has been a crucial component of the most recent advancements in pharmaceuticals.