T2 - Modified-Release Drug Products and Other Drug Devices Flashcards
What are modified-release drug products?
Products that alter the timing and/or rate of release of the drug substance from the formulation
What are modified-released dosage form?
Formulation in which the drug-release characteristics of time and/or location are chosen for therapeutic effect or convenience
What are the categories of modified-release?
- Extended-release drug products
- Delayed-release drug products
What is delayed release?
- Dosage form that releases a small portion of drug at a time other than the immediate release after administration
- An initial portion may be released after administration
What is an example of a delayed-release?
Enteric-coated dosage forms
What is extended release?
A dosage form tha allows at least a 2fold reduction in dosage frequency as compared to immediate release
What is the purpose of using extended release?
- Prevents very rapid absorption of drug
- Extended action at a predetermined rate for a specific duration
- Release at a specific site
What are the advantages of using extended-release formulations?
- Less fluctuation in drug blood levels
- Frequency reduction in dosing
- Enhanced convince and compliance
- Reduction in adverse side effects
- Reduction in overall health care costs
How does extended-release cause less fluctuation in drug blood levels?
Controlling rate of release eliminates peaks and valleys of blood levels
How does extended-release allow frequent reduction in dosing?
Deliver more than a single dose, hence may be taken less often than conventional forms
How does extended-release enhance convince and compliance?
With less frequency of dosing, a patient is less apt to neglect taking a dose, greater convince with day and night administration
How does extended-release reduce adverse side effects?
Fewer blood levels outside therapeutic range
How does extended-release reduce overall health care costs?
Overall cost of treatment may be less due to enhanced therapeutic benefits
What are the disadvantages of extended-release?
- Dose dumping
- Less flexibility in accurate dose adjustment
- Less possibility for high dosage
What is dose-dumping?
The release of more than the intended fraction of drug or as the release of drug at a greater rate than the customary amount of drug per dosage interval
Why is extended-release less flexible in accurate dose adjustment?
More difficult to remove drug or adjust dose if adverse effect occurs
Why is it less possible to receive high doses for extended release?
Product may contain two or more times the dose given at more frequent intervals, drugs that require high single doses may have to be too large for the patient to swallow easily
What are examples of extended release dosage formulations?
- Pellets
- Granules
- Microspheres
Describe the formulation of slow-release seeds or beads?
- Sugar
- Starch
- Lactose
- Microcrystalline cellulose spheres (more durable)
What is a multi-tablet system?
- Usually capsules containing multiple mini-tablets (8-10)
- Tablets can have different release characteristics
What is micro encapsulations?
A process of encapsulating microscopic drug particles with a special coating material, making the drug particles more desirable in terms of physical and chemical characteristics
What are the advantages of micro encapsulation?
Administered dose of a drug is subdivided into small units that are spread over a large area of the GIT, which may enhance absorption by diminishing local drug concentration
What are the types of matrix systems?
- Gum-type
- Polymeric
What are the characteristics of gum-type matrix systems?
- Methycellulose, veegum, alginic acid, tragacanth
- Biodegradable
- Alter degradation based on hydration control, pH dependence, thickness and viscosity
What are the characteristics of polymeric matrix?
- Nonbiodegradable or biodegradable
- Hydrophilic or phobic
- Non-biodegradable is cautioned for reduced GI motility
- Used for implants and oral admin
How do you prepare a less soluble drug in a matrix?
The drug may be granulated with an excipient to slow dissolution of the drug
What happens when ionic exchange resin is exposed in the GIT?
Cations in the gut (K+ and Na+) will displace the drug from the resin releasing the drug
What are layers of an osmotic pump core?
- Active: containing drug
- Push: pharmacologically inactive, but osmotically active
What happens to an osmotic tablet when it enters the GIT?
Pressure increases in the osmotic later and pushes against the drug layer, releasing the drug from the laser drilled orifice. Altering size of orifice will affect the release rate
How fast is the drug delivery for osmotic pump tablets?
Constant as long as the osmotic gradient remains constant