Delayedrelease

Delayed release is a term used in pharmacology to describe a dosage form that releases its active ingredient some time after administration, rather than immediately. The delay can serve several purposes: protecting the drug from degradation in the stomach, targeting release to a specific region of the gastrointestinal tract, or aligning drug release with circadian or dosing requirements. Delayed-release dosage forms include enteric-coated tablets and capsules, time-delay systems, and pH-sensitive coatings. The resulting release profile may involve dissolution in the intestine, a scheduled lag, or triggers that initiate release after a set period.

Mechanisms commonly employed include enteric coatings, which are resistant to stomach acid but dissolve at higher intestinal pH to release the drug in the small intestine or colon. Time-delay systems use coatings or materials that postpone release for a predefined period, or release after a delay triggered by a cue. Other strategies involve multi-layer tablets or osmotic pumps that initiate release after a lag.

Applications include reducing gastric irritation and improving tolerability for certain drugs, targeting therapy to specific GI regions, smoothing plasma concentration fluctuations, and extending duration of action to reduce dosing frequency. Delayed-release formulations are also used when a drug should act after absorption in a particular part of the digestive tract or at a specific time.

Relation to other terms: Delayed-release differs from immediate-release, which releases promptly, and from extended- or sustained-release, which prolongs release after onset. Regulatory labeling typically specifies delayed-release characteristics and requires testing to confirm the intended lag time and release profile.