Modified Drug Release Flashcards
What are modified release tablets?
they are tablets that are modified in order to maintain therapeutic plasma levels
The active drug are delivered at?
- desired rates
- predetermined time point
- specific duration
- specific site the gastrointestinal tract
What are the characteristics of modified release oral dosage forms?
- extend the circulation of time in the body
- provide immediate release and then is followed by a predetermined release time
- improves patients adherence *
- improve therapeutic outcomes *
What are the different classifications of release patterns?
- Extended release
- Delayed release
- Prolonged release
- Sustained release
- Controlled release
What is extended release?
modifies drug dissolution by controlling the access of biological fluids to the drug using barrier coatings
What are common coating agents for extended release technology?
- beeswax
- carnauba wax
- ethyle cellulose
- cetyl alcohol
What is delayed release?
when you release the contents of a drug at a different time other than immediately after administration
Is the a delayed release slow or rapid?
rapid
What are gastro-resistant tablets?
the drug passes through the stomach unchanged due to enteric coating, but is then released in the small intestine
True or False: Delayed release can be combined with prolonged treatment release for local treatment of the colon
True
What is a pulsatile release?
drug is released in two or more pulses to increase the time period for drug absorption after a single dose
What is a gastro-retentive system?
a drug (extended release) remains in the stomach for an extended period of time
What is prolong release?
preparations could be a single unit or multiple unit dosage form
What is repeat action release?
two doses of medication are provide and then delayed release happens after
ex. a two layered tablet where one is immediate release and the other is delayed release (second dose)
Constant release follows what type of kinetics?
Zero-order
Declining drug release follows what type of kinetics?
First-order
What is diffusion-controlled release?
the drug is transported by diffusion through pores that are filled with gastric and intestinal fluid; the fluid pierces the dosage forms and dissolves the drug and creates a concentration gradient and diffuses out through the release unit
True or False: Drug release is achieved by diffusion through the coating
True
True or False: Drug particles located at the surface of the release unit will be dissolved and released rapidly
True
True or False: Dissolution of the drug in the GI fluid is not the release controlling step for drug absorption
False; it is
The rate of drug release is controlled by the amount of fluid that is present in the matrix in which the drug is dispersed
False; erosion
What is erosion controlled release?
The rate of drug release is controlled by the erosion of the matrix in which the drug is dispersed
What is osmotic-controlled release?
Flow of liquid into the drug release unit is driven by osmotic gradient between the inside and outside of the release unit
What are the advantages of modified release drugs?
less fluctuation of blood levels
better adherence*
less frequent administration*
What are the disadvantages of modified release drugs?
lack of flexibility with dose adjustments
risk of dose dumping
What are the ideal properties of modified release drugs?
- dose size should be small *
- short half lives *
- narrow therapeutic index
- must be uniformly absorbed by the GIT
- Aqueous solubility
- First Pass Metabolism
What are examples of modified-release dosage forms?
- Bupropion Tablets
- Methylphenidate Tablets
- Dexymethylphenidate
- Metformin HCL
