extendedrelease

Extended-release refers to pharmaceutical formulations designed to release a drug over an extended period after administration, creating a prolonged therapeutic effect and reducing dosing frequency. They are designed to maintain steadier drug levels in the body compared with immediate-release formulations, which release the active ingredient quickly after dosing.

Release mechanisms used in extended-release products vary. They include matrix systems where the drug is dispersed in a polymer matrix that controls diffusion, coated beads or pellets with barriers to diffusion, osmotic pump devices that use osmotic pressure to control release, ion-exchange resins, and reservoir-type systems with rate-controlling membranes. Some products are designed to release drugs in a pH-dependent or pH-independent manner, depending on where in the gastrointestinal tract absorption occurs.

Common nomenclature for these products includes terms such as extended-release (ER), prolonged-release (PR), controlled-release (CR), and sustained-release (SR or SA). Marketers often add suffixes like XR, LA, CR, SR, or SA to the drug name to indicate extended release.

Advantages of extended-release formulations include more stable plasma concentrations, improved adherence due to reduced dosing frequency, and fewer peak-trough fluctuations. Limitations include the potential for reduced onset of action in acute situations, the risk that crushing or chewing the product can disrupt the release mechanism and increase exposure, and variability in absorption with food or other factors. They may also be more expensive and require careful dose adjustments in certain populations.

Regulatory considerations encompass clear labeling of dosing and release characteristics, demonstration of bioequivalence to reference products where relevant, and in vitro dissolution testing to ensure consistent performance.