pharm 125 - modified release

Majority of the modified release drugs are class ___

1

Modified release is further broken down into ____ and _____ release

delayed, extended

Conventional vs. modified:

In which do plasma concentrations peak very quickly?

conventional

T/F the goal of modified release is to improve therapeutic profile and minimize side effects

T

On a drug blood levels vs time graph, does a controlled released product have peaks and valleys?

no

What is MEC and MTC?

MEC = min effective concentration

MTC = max toxic concentration

Controlled release, prolonged release and sustained release are interchangeable with _______ release

extended

Do modified release drugs increase the accumulation of drugs in the body?

no, they decrease it

Which has reduced GI side effects?

MR

Which has less drug overall, conventional or modified release?

MR

What can occur with modified release if it is not sealed properly?

dose dumping

What may happen to modified release dosage forms that remain intact

lodged along GI tract

T/F modified release requires additional patient education

T

Is it difficult to remove modified release dosage form from the system?

no

Doses _______ can be hard to formulate

>500mg (large dose)

Drugs ____ _____ in the GI tract

stay longer

______ aqueous drugs are not suitable

low (<0.1mg/mL)

Do WA or WB work better as modified release?

WB, no precipitate

Ideally, the log P should be between ___ and ____

1, 3

Drug candidates should have a half life of ___ to ____

2h to 8h

It is hardest to design a drug that goes to the _____

colon

Can food intake influence drug release rate?

yes, can increase or decrease it

Dose dumping is problematic for ____ potent drugs with ____ therapeutic ranges

highly, narrow

Most extended release systems show ____ order kinetics

1st

T/F extended release systems are dependent on [drug]

T, 1st order

Reservoir diffusion systems involve a drug in the core surrounded by an inert ____ ______ polymeric membrane

H2O insoluble

A _____ polymeric membrane is more common

porous, ex: PEG

The rate of release of a reservoir diffusion system depends on ___ law

Fick’s ([ ] gradient)

What are the components of a reservoir system?

core and coating

How are reservoir diffusion systems prepared?

coated granules/pellets (ex: bottom spray)

encapsulate in hard capsule or compress into tablet

____ diffusion systems are the most common

matrix

______ diffusion system involves drug dispersed homogeneously through an inert, insoluble or swellable polymer

matrix

A hydrophilic matrix or swellable soluble matrix is an example of a matrix diffusion system. drug release is controlled by ____ of the drug out of the gel layer and is ___ or ____ order release

diffusion, 0 or 1st

An erosion controlled matrix is suitable for ____ soluble drugs. It is close to ___ order

low, 0

Inert polymer matrix systems are ___ order and involve _______ matrices

1st, hydrophobic

What are the 3 types of hydrophilic matrix diffusion systems?

diffusion, diffusion + erosion, erosion

What is the rate controlling step for hydrophilic matrix diffusion systems?

diffusion of drug out of matrix

Diffusion is ___ order, diffusion and erosion is___ order, and erosion is ___ order

1st, mix of 1st and 0, 0

Osmoticallly controlled systems use _____ pressure ad a driving force to generate constant drug release

osmotic

Osmotically controlled systems provide ___ order release

0

What are the 2 types of osmotically controlled systems?

EOP (elemental osmotic pump) - single layer

PPOP (push pull osmotic pump)- bilayer

polyethylene oxide (PEO) is an example of a ____ agent

swelling

Push-pull osmotic pump has ___ layers. The _____ layer swells and pushes the drug out.

2, push

______ ______are insoluble copolymer matrices with ionizable groups capable of exchanging ions

ion-exchange resins (IER)

____ and _____ are prepared as beads or pellets

drug + resin

Ion-exchange resins can only be used for ____ drugs

ionized

A ____ exchange resin is used for basic drugs

cation

A(n) ______ exchange resin is used for acidic drugs

anion

What are the general steps to an ion-exchange resin?

1. resin + drug into beads/pellets

2. load drug onto exchange resin

3. exchange ions with resin

What is the goal of gastric retentive systems?

increase drug time in the stomach

An ideal drug candidate for gastric retentive system is stable and soluble at ___ pH

low, WB best

What are the 5 types of gastric retentive systems?

floating

sedimentation

expansion (swelling)

expansion (unfolding)

mucoadhesion

What are oral colonic drug delivery pH controlled systems?

delayed release, reach colon, good for IBD

What is a pro to pH controlled systems?

colon has fewer enzymes

How does a pH controlled system work?

1. H2O soluble cap dissolves

2. hydrogel plug expands

3. hydrogel plug ejects in large intestine releasing drug

Concerta uses _____ ______

osmotic pressure

Biphentin has _______ _____

mutli-layer beads

What is the role of cellulose acetate?

membrane, insoluble

What is the role of polyethylene oxides?

swelling agent (push/pull polymer)

What is the role of NaCl?

osmotic agent, increase pressure in tablet

What is the role of sugar spheres?

inert core

What is the role of TiO2?

opacifier

What is the role of cellulose compounds?

matrix, coating

What is the role of lactose?

filler

What is the role of Mg stearate?

lubricant