Modified Release Dosage Forms Flashcards
What is a sustained release system?
include any drug delivery system that achieves slow release of drug over extended period of time
What is a controlled-release system
If a sustained-release system is successful at maintaining constant drug levels in the target organs, it is considered a controlled-release system
What is a prolonged-release system.
If the sustained-release system prolongs therapeutic levels of the drug it is considered a prolonged-release system.
What is a Extended release systems
allow reduction in dosing frequency from that necessitated by a conventional dosage form (FDA definition).
What is a Delayed release systems
release the drugs at a time other than promptly after administration. The delay may be influenced by pH (like enteric coated formulations).
What is a Targeted release
isolates or concentrates the drugs in a specific body region, tissue or organ e.g. tumors Nanomedicine – targeted drug delivery
What is a Repeat action
forms usually contain two or more single doses of the drug, one for immediate release and the second for delayed release
What is Conventional dosage form
Normal take a pill it has an action and it metabolizes normally
What are the examples for preparing delayed action formulation?
- Entric coated
- Rheumatoid Arthritis
- Morning Sickness
XL products provide
an immediate release of drug, which promptly produces the desired therapeutic effect, which then is followed, by the gradual, and continual release of additional amounts of drug to maintain its effect over a period of time.
Sustained plasma levels provided by XL drug products often
eliminate the need for night dosing
What is the difference between Immediate Release/Sustained Release and extended-release?
Immediate has a shorter duration as compared to Sustained release, and Extended-release has a longer duration compared to the two
What are a few design variabilities in MRDFs that need to be considered?
a) Route of delivery
b) Type of delivery system
c) Disease being treated
d) The patient
e) Length of therapy
f) Properties of the drug
-physicochemical -biological
What are drug candidates for MRDFs?
Solubility
Partition Coefficient (move between membranes)
Stability (In and out)
Rate of absorption
Ability of drugs for complexation
Good margin of safety
Used for chronic conditions rather than acute
Dose
What solubility is MRDF not possible?
<0.01
What property affects the ability of the drugs to diffuse through the polymers used in the design of MRDFs
Partition coefficient
Slow kinetics
not necessary to prepare MRDFs
Fast kinetics
very large amounts will be required to design MRDF
Narrow therapeutic window
Not suitable due to product defect or incorrect administration
What is the maximum dose size for oral formulations?
0.5-1gram
What are the two categories of dissolution systems?
a) Membrane dissolution systems
b) Matrix dissolution systems
What is Membrane Dissolution Systems?
Different groups of particles have different membrane thicknesses that dictate their release
or
Layers of sugar and drug
What are matrix dissolution systems?
Drug is dispersed with different sized granules that have different dissolution times
Usually in the form on a tablet/capsule where hydration releases it
What is a diffusion system?
Release rate of a drug is determined by its diffusion through a water-insoluble polymer (Coating)
Two types of diffusion devices
Membrane Diffusion (Reservoir devices)
(core is surrounded by a polymeric membrane).
Matrix Diffusion (Matrix device) (drug is distributed uniformly in an inert polymeric matrix).
Dissolution
a drug that is located inside the reservoir which is released
Diffusion
of drug across membrane - rate controlling step.
Matrix Diffusion Devices
Drug is dispersed homogenously in the matrix which DOES NOT dissolve or erode
Diffusion of the drug from the matrix to outsideà Rate limiting step
Capsule will be excreted
Membrane-Matrix Hybrid example
IUD
What are OSMOTIC SYSTEMS?
Osmotic pressure can be employed as the driving force to generate a constant release of drug, provided that constant osmotic pressure is maintained.
Water comes in and pushes drug through a small hole
