7 Questions
Which type of drugs, according to the Biopharmaceutics Classification System, are most suitable for extended-release delivery?
Type I: high solubility, high permeability
In which type of drug release mechanism can drug release from dosage forms be the rate-limiting step?
Diffusion-based release mechanisms
What type of polymer is typically used in hydrophilic matrix systems for extended release?
Water-swellable, hydrophilic polymer
Which category of drugs exhibits low solubility and low permeability according to the Biopharmaceutics Classification System?
Type IV
Which type of matrix systems is used for extended (sustained) release of drugs?
Insoluble polymer matrix
What kind of drug behavior can give inherent sustained-release behavior in drugs with low solubility?
Low rate of dissolution
What process is used to manufacture tablets in hydrophilic matrix systems?
Direct compression or roller compaction (dry granulation processes)
Study Notes
Insoluble Polymer Matrix
- Consists of an inert matrix system where the drug is embedded in an inert polymer
- Structure is likened to a sponge, with drug molecules dispersed throughout
- Drug release is controlled by pore size and number of pores, and tortuosity
Mechanism of Drug Release
- Drug release does not follow zero-order kinetics
- Drug release decreases with time due to increasing distance drug molecules have to travel to reach the surface of the device
Membrane-Controlled Systems
- Differ from matrix formulations in that the rate-controlling part is a membrane through which the drug must diffuse
- Drug is concentrated in the core and must traverse a polymeric membrane or film, slowing down the release rate
Hydrophilic Matrix Systems
- Also referred to as swellable soluble matrices
- Used for extended (sustained) release
- Drug is mixed with a water-swellable, hydrophilic polymer and compressed into a tablet
- Polymer is usually in the form of a powder or granule, and tablets are manufactured by direct compression or roller compaction (dry granulation processes)
Biopharmaceutics Classification System
- Classifies drugs into four categories based on solubility and permeability
- Type I: high solubility, high permeability
- Type II: low solubility, high permeability
- Type III: high solubility, low permeability
- Type IV: low solubility, low permeability
Extended Release
- Hydrophilic matrix systems
- Insoluble polymer matrix
- Membrane-controlled systems
- Osmotic systems
- Gastroretention
Learn about insoluble polymer matrices used in drug delivery systems, where the drug is embedded in an inert polymer structure resembling a sponge. Explore how drug release is controlled by pore size and number of channels in these systems.
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