This document discusses sustained release and controlled release drug delivery systems. It defines sustained release as slowly releasing a drug over an extended period of time in a non-specific, non-predictable manner showing first-order kinetics. Controlled release maintains constant drug levels by releasing the drug in a site-specific, predictable and reproducible zero-order kinetic profile. The advantages of these systems include improved efficacy, safety, patient compliance and minimized side effects by preventing fluctuations in drug levels. Challenges include reduced dose adjustments, stability issues and delayed drug action.

1. 1
SUSTAINED RELEASE
&
CONTROLED RELEASE
FORMULATION
By :
Dr. Umesh Kumar Sharma and Shyma M S
Department of Pharmaceutics,
Mar Dioscorus College of Pharmacy,
Alathara, Sreekariyam,
Thiruvananthapuram, Kerala, India

2.  The Term ”Drug delivery systems” refer to the
technology utilized to present the drug to the
desired body site for drug release and absorption.
 DDS is the interface between the patient & the
drug.
 Newer discoveries and advancements in
technology has lead to various new techniques of
delivering the drug for maximum patient
compliance at minimal dose and side effects.
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3. IDEAL DRUG DELIVERY SYSTEM
It should deliver drug at a rate dictated by the needs of
the body over the period of the treatment.
It should channel the active entity solely to the site of
action.
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4. This is achieved by development of new various
modified drug release dosage forms like
• Control release dosage forms.
• Time release dosage forms.
• Sustained release dosage forms.
• Site specific or targeted DDS.
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5. 5

6. SUSTAINED RELEASE DOSAGE FORMS
Sustained drug delivery may provide an immediate dose
required for the normal therapeutic response, followed
by the gradual release of drug in amounts sufficient to
maintain the therapeutic response for a specific extended
period of time usually 8-12 hours.
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7. 7
COMPARISON OF DRUG RELEASE PROFILE

8. • The basic goal of therapy is to achieve steady state
blood level. That is therapeutically effective and non
toxic for an extended period of time.
• Sustained release provide promising way to decrease
the side effect of drug by preventing the fluctuation
of the therapeutic concentration of drug in the body
and increase patient compliance by reducing
frequency of dose.
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9. CONTROLLED RELEASE DOSAGE FORMS
Controlled drug delivery is one which delivers the drug at
a predetermined rate, for locally or systematically, for a
specific period of time.
• Continous oral delivery of drug at predictable &
reproducible kinetics for pre determined period through
out the course of GIT
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10. SUSTAINED
RELEASE
Slow release of drug over an
extended period of time.
Non specific site.
Release of drug is con:
dependent.
Non-predictable &
reproducible.
They show 1st order.
CONTROLLED
RELEASE
Maintain a constant drug level
in blood or tissue.
Site specific.
 Release of drug is con:
dependent.
 Predictable and reproducible.
 They show zero order.
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SUSTAINED RELEASE & CONTROLLED RELEASE

11. ADVANTAGES
OF SUSTAINED RELEASE PRODUCTS
 Decreased local and systemic side effects so reduced GI
irritation.
 Better drug utilization and reduction in total amount of
drug used.
 Improved efficacy in treatment ,optimized therapy,
more uniform blood concentration.
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12.  Minimize dose accumulation by chronic dosing.
 Better patient acceptance and compliance.
 Improved efficacy safety ratio.
 Method by which sustained release is achieved can
improve the bioavailability of some drugs.
 Reduction in fluctuation in drug level and hence
more uniform pharmacological response.
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Con…

13. DISADVANTAGES
OF SUSTAIN RELEASE PRODUCTS
 Reduced potential for accurate dose adjustment.
 Need of additional patient education.
 Stability problems.
 Increased potential for 1st pass metabolism.
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14. Reduced drug absorption may delay on set of action.
Reduction in systemic availability ,has been shown
for some SR formulations of theophylline,
procainamide.
Sustained release does not permit immediate
termination of therapy.
More costly process and equipment are needed in
manufacturing of SRDDS.
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Con..

15.  Dose dumping
Is phenomenon of drug metabolism in which
environmental factors can cause the premature and
exaggerated release of drug.
This can greatly increase the of drug in the body and
there by produce adverse effects or even drug induced
toxicity.
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16. CONCEPT OF
SUSTAINED RELEASE FORMULATIONS
The concept is divided in to two considerations
 Release rate consideration
 Dose consideration
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17. RELEASE RATE CONSIDERATION
In conventional dosage form Kr > Ka release of drug
from dosage form is not a rate limiting step.
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Drug
release
kr Absorption
pool
ka
Drug
absorption
Target
area
ke
Drug
elimination
Dosage
forms

18. In immediate release,
kr>>ka
where as in non immediate release
kr<<<ka
therefore release is rate limiting step.
Altering kr we can get an effective SR formulation.
The release should follow zero order kinetics (clinically
equivalent to constant release in many cases.
kr = rate in = rate out = ke*vd*cp
where: ke = elimination rate constant (1st order kinetics.)
vd = total volume of distribution
cp = plasma drug concentration
kr = zero order release rate constant
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19. DOSE CONSIDERATION
o Initial (primary) dose = Di
o Maintenance dose = Dm = kr* Td
where, Td = total time required for extended
release dosage form.
Therefore, total dose -
W =Di+Dm
W=Di +Kr *Td
If maintenance dose begins to release the drug during
dosing t=0 then,
W=Di+Kr*Tp
Tp = time of peak drug level. 19

20. By :
Dr. Umesh Kumar Sharma and Shyma M S
Department of Pharmaceutics,
Mar Dioscorus College of Pharmacy,
Alathara, Sreekariyam,
Thiruvananthapuram, Kerala, India
THANK YOU