Oral modified release drugs Flashcards
Define modified release drugs
- Modified-release drug delivery refers to the manipulation or modification of drug release from a dosage form (e.g., tablet, pellet, capsule) with the specific aim of delivering API at:
desired rate
pre-defined time points
specific sites in the gastrointestinal tract
Three types of modified release drugs
- Delayed-release dosage forms – drug is not released immediately but after some time
- Gastro-resistant dosage forms (enteric dosage forms) – drug is not released in the stomach at low pH but will be released in the small intestine at higher pH
- Extended-release dosage forms (prolonged/sustained/controlled release dosage forms) – drug plasma levels are sustained for longer periods reduction in dosing frequency better compliance
The site of action of oral modified drug delivery systems
What modified-release drug delivery means for the patient
What modified-release drug delivery means for the healthcare professional and pharmaceutical industry
- Possibility to tailor treatment for patient needs
- Product life extension (product’s patent life)
- Higher development costs
- Cost savings to healthcare providers
Physiological considerations for modified-release oral drug delivery
- pH
- Fluid
- Transit time
Mechanisms controlling the rate and extent of drug release:
- Hydration of the device (either swelling or dissolution of some components of the dosage form)
- Diffusion of water into the device
- Dissolution of drug
- Diffusion of the dissolved drug out of the device
Gastro-retentive systems
Hydrophilic matrix systems
Swellable soluble matrices (e.g., hydroxypropyl cellulose, polyethylene oxide) used for extended (sustained) release
Drug is mixed with water-swellable or water-soluble polymer along with other excipients
Effect of polymer nature on drug release characteristics
How does a ‘membrane-controlled’ MR drug work
How does an ‘osmotic pump system’ drug work
Delayed release with gastro-resistant coating
X is a type of extended-release, which keeps the drug in the upper GI tract
Gastroretention is a type of extended-release, which keeps the drug in the upper GI tract
