Topic overview

Start with the big picture

These formulations are designed to maintain therapeutic plasma levels, reduce dosing frequency, support adherence, limit peak–trough fluctuations, and minimize side effects. The lesson distinguishes controlled release from sustained release and considers the properties that may make a drug suitable for these systems. It surveys release mechanisms such as diffusion, dissolution, polymer erosion, osmotic pressure, and ion exchange, alongside architectures including matrix and reservoir devices, osmotic pumps, depots, and other delivery formats. Formulation variables—including polymer properties, drug–polymer ratio, particle size, and coating characteristics—can influence release. Mathematical models help describe release profiles, while in-vitro and in-vivo evaluation approaches assess system performance.