Controlled Drug Delivery Systems
                     CONTROLLED 
DRUG 
DELIVERY 
SYSTEMS
INTRODUCTIO
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Controlled drug delivery systems are being 
developed at a high rate because of the 
many advantages they offer in therapy. 
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ADVANTAGE
One advantage is their ability to deliver the 
active drug at a constant rate over a 
prolonged period, without delayed onset of 
action and without interference by gut 
physiology or other external conditions.
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REDUCES THE 
RISK OF SIDE 
EFFECTS
The precision in which the rate of drug 
release is known reduces the risk of side 
effects. It also increases patient compliance 
due to longer periods between dosing. 
Finally, it achieves better therapeutic effect 
as a result of all these factors.
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CHEMICALLY-
CONTROLLED 
SYSTEMS
Among these novel drug delivery systems 
are the chemically-controlled systems. 
These are dependent upon chemical 
reaction to release the drug from the 
polymer within which it is contained. 
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BIO ERODIBLE
The polymer is bio erodible, which means 
that the device will degrade and doesn’t 
need to be removed from the body after use. 
The process through which these polymers 
pass through a human body must be verified 
through rigorous preclinical testing, in order 
to ensure their safety.
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BIOEROSION 
SYSTEM
The bioerosion system, also called the 
biodegradation system, is based upon the 
degradation of the polymer within which the 
drug is uniformly distributed, into smaller 
molecules which are readily soluble in water.
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POLYMER MATRIX 
CONTROLS
In most cases, the polymer matrix controls 
the release of the drug which is evenly 
dispersed within it. The breakdown of the 
polymer leads to the entry of water, which 
causes the drug to dissolve on contact and 
be released.
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FACTORS
• The hydrophilic nature of the polymer
• The porosity of the device
• The presence of any components which 
can dissolve in water
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PENDENT CHAIN
By this mechanism, the drug is not 
incorporated physically into the polymer.  
Instead, it is attached to its backbone 
through a reactive chemical bond which 
easily gives way in the presence of water or 
certain enzymes. 
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THANK YOU
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