Controlled drug delivery 1 Flashcards

1
Q

What are controlled drug delivery systems?

A

Preparations designed in such a way that the release rate or location of active drug is controlled

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2
Q

What are 4 reasons for using controlled drug delivery systems?

A
  1. Reduce fluctuations in drug plasma concentrations
  2. Reduce dosing frequency-improve patient compliance
  3. Control delivery site
  4. Timed release
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3
Q

What are enteric coatings?

A

Tablets coated with a polymer that is insoluble in the highly acidic stomach, but dissolves int eh small intestine (>pH 5.5)

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4
Q

What kind of polymers are available for enteric coatings?

A

Cellulose derivatives

Methacrylic acid co-polymers

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5
Q

What is the release area for Eudragit D-55?

A

Duodenum

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6
Q

What is the release area for Eudagrit 100?

A

Jejunum

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7
Q

What 4 mechanisms are there for controlling drug release?

A

Water penetration controlled DDS
Diffusion-controlled DDS
Chemically-controlled DDS
Responsive DDS

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8
Q

What is used for swelling-controlled devices?

A

Hydroxypropyl methylcellulose

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9
Q

What is the release rate affected by for swelling controlled devices?

A

Polymer MW, concentration and chemical structure.
Drug concentration, solubility and location.
Geometry of tablet and modifications.

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10
Q

How is Geomatrix technology composed?

A

Hydrophilic HPMC core containing the drug.

One or two drug-free barrier layers which control swelling and surface area of core.

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11
Q

What are 8 different control capabilities that swelling controlled devices are capable of?

A
Zero order
Quick slow
Slow quick
Binary
Positioned
Accelerated
Delayed
Multiple pulse
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12
Q

What is TIMER controlled release delivery system composed of?

A

Locust Bean Gum (LBG)

Xanthan

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13
Q

What does release rate of TIMER controlled release delivery system depend on?

A

LBG:X ratio
Drug concentration
Additional components-salts and water
Construction of tablet

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14
Q

What kind if delivery is possible for TIMER controlled release delivery system ?

A

Zero order
First order
Burst
Delayed

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15
Q

What steps are involved in TIMER controlled release delivery system ?

A

Water influx
Matrix swelling
Drug diffusion
Matrix erosion

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16
Q

What is the advantage of GEMINEX delivery technology?

A

Its ability to develop a combination drug product that has twp unique release profiles

17
Q

What does a SyncroDose tablet consist of?

A

An inner core of drug and a surrounding compression coating containing TIMER based materials

18
Q

What is lag time controlled by for SyncroDose tablet?

A

Variations in the two polysaccharides- xantham gum and locust beam gum

19
Q

How does SyncroDose tablet delivery system work?

A

Controls rate of water ingress into coating and subsequent disintegration of core.

20
Q

What can be modified for SyncroDose tablet to control release rate?

A

Coating layer

21
Q

What happens to the coating of swelling controlled delivery systems after 0.37 hours?

A

Enters the stomach and outer polysaccharide begins to swell

22
Q

What happens to the coating of swelling controlled delivery systems after 1.6 hours?

A

Proceeds along GIT and erosion of tablet coating begins to occur but substantial amounts remain in contact with the core preventing drug release

23
Q

What happens to the coating of swelling controlled delivery systems after 3.42 hours?

A

entire coat has eroded and dispersed

24
Q

What happens to the core of swelling controlled delivery systems after 0.37 hour?

A

Enters stomach and core remains intact

25
Q

What happens to the core of swelling controlled delivery systems after 1.6 hour?

A

Prior to tablet entering small intestine the core retains its integrity

26
Q

What happens to the core of swelling controlled delivery systems after 3.42 hour?

A

Tablet continues to move through intestinal tract, core rapidly disintegrates following exposure due to completion of coat erosion process

27
Q

What are the advantages to Contramid?

A
High drug loading capacity
Flexible release profiles
Ability to release multiple drugs from a single tablet with different release rates
Safe
Completely biodegradble
28
Q

In osmotically controlled devices what is the drug mixed with?

A

Water-soluble core material

29
Q

In osmotically controlled devices what is the core surrounded by?

A

Water insoluble semi-permeable polymer membrane in which is laser drilled a small orifice.

30
Q

What is formed within an osmotically controlled devices when water diffuses into the core?

A

Concentrated solution

31
Q

How is the drug pushed out through the hole of a osmotically controlled device?

A

Osmotic gradient

32
Q

How is the release rate of a osmotically controlled device tailored?

A

Modify excipients