this topic is related to sustained drug delivery systems

1. SUSTAINED RELEASE DRUG
DELIVERY SYSTEM
Presented By-;
TARIQ HUSAIN
M.PHARM
[PHARMACEUTICS]
23MPH10001
Chandigarh University

2. INTRODUCTION
Sustained release, sustained action, controlled release, extended action,
timed release dosage forms are the terms used to identify drug delivery
systems that are designed to achieve a prolonged therapeutic effect by
continuously releasing medication over an extended period of time after the
administration of single dose.
 Now a days Newer discoveries and advancements in technology have led
to various new techniques of delivering the drugs for maximum patient
compliance at a minimal dose and side effects.

3. IDEAL DRUG DELIVERY
SYSTEM
 Firstly, it should deliver the drug at a rate dictated by the needs of the
body over the period of treatment.
 It should be easy to administer to the patient.
 It should be safe and reliable.
 It should be cost-effective
But, there are some confusion in terminology between “Controlled
release”& “Sustained release”
Sustained release- In sustained release system are designed to
achieve a prolong therapeutic effect by continuous releasing
medication over a period of time. They do not attain zero order
kinetics .it may be may not be controlled.
Controlled release-Controlled release associated with those system
from which therapeutic agent may be delivered at ‘’predefined rates
over a long period of time ‘’. It maintain constant level in drug level
concentration. It can be controlled.

4. SUSTAINED RELEASE DRUG
DELIVERY SYSTEM
Graph showing differences between all the three
dosage formulations

5. ADVANTAGES
o Improved patient compliance
o Less frequent dosing
o Allows whole-day coverage.
o Decreased local and systemic side effects.
o Decreased GIT irritation.
o Decreased local inflammation and better drug utilization.

6. DISADVANTAGES
o DOSE DUMPING: The increased quantity of
drugs released causes the dumping of drugs
which in turn leads to toxicity.
o Retrieval of drug is difficult.
o Need for additional patient education[awareness].
o Higher cost of formulation.

7. CLASSIFICATIONS OF ORAL
SUSTAINED
RELEASE SYSTEM
o Diffusion-controlled Systems
a)Reservoir devices
b) Matrix devices
o Dissolution-controlled systems
a) Matrix dissolution controlled systems
b) Encapsulation dissolution controlled systems
o Diffusion and dissolution-controlled systems
o Ion exchange resin-drug complexes
o Hydrodynamic pressure
o Osmotic pressure

8. FACTOR AFFECTING THE
FORMULATION
1.Physiochemical –
a. Route of administration
b. Molecular weight
c. Dose size
d. Protein binding
2.Pharmakokinetic-
a. Absorption
b. Distribution
c. Metabolism
d. Excretion
3.Pharmacodynamic-
a. Therapeutic index
b. Plasma conc. Response relationship

9. CHARACTERISTICS OF DRUGS
USED FOR SUSTAINED RELEASE
 Drug must be released from the dosage form at a
predetermined rate.
 Dissolve in the gastrointestinal fluids.
 Maintain sufficient gastrointestinal residence
time.
 Absorbed at a rate that will replace the amount of
drug being metabolized and excreted.
 Should follow zero-order drug release.

10. PREFORMULATION STUDIES
 It is defined as the phase or study of research and development in
which pre-formulation studies characterize physical and chemical
properties of a drug molecule in order to develop safe, effective and
stable dosage form.
 Determination of Melting Point:
 The melting point of the drug was determined by the capillary method.
o Solubility:
 The solubility of the drug was determined in pH 1.2 and pH 6.8 buffers.
 Solubility Studies were performed by taking an excessive amount of
drug in beakers containing the Solvents.

11. METHODS FOR PREPARATION OF
SUSTAINED-RELEASE TABLETS
 Wet Granulation Technique
 Milling and gravitational mixing of drug,
polymer, and excipients.
 Preparation of binder solution.
 Wet massing by addition of binder solution or
granulating solvent
 Screening of wet mass.

12. MATERIALS USED IN COATING OF
SUSTAINED RELEASE PRODUCT
o Mixture of waxes: bees wax, carnauba wax.
o Shellac and zein
o Ethylcellulose
o Acrylic resin
o Cellulose acetate

13. POLYMERS USED FOR
MICROENCAPSULATION
o Water soluble resins: Gelatin, povidone, CMC,
PVA
o Water-insoluble resins: Ethylcellulose,
Polyamide, Polyethylene, Cellulose nitrate
o Waxes and lipids: Paraffin, carnauba, beeswax,
stearic acid, stearyl alcohol

14. MARKETED FORMULATIONS
Name Marketer Dosage form Indication
Carbotrol Shri US Oral capsule Epilepsy
Glucotrol X1 Pfizer Oral tablet Hyperglycaemi
a
Adderall XR Shri US Oral capsule ADHD
Procardia X1 Pfizer Oral tablet Angina
Ortho Evra Ortho-Meneil Transdermal
patch
Contraceptive
Duragesic Janssen Transdermal
patch
Chronic pain

15. CONCLUSION
 SRDDS is usually apprehensive with maximum
drug availability by an attempt to get a maximum
rate and extent of drug absorption however;
controls of drug action through formulation also
imply controlling bioavailability to decrease drug
absorption rates.
 SR formulations are helpful in increasing the
efficiency of the dose as well as they are also
improving the patient’s compliance and
expediency due to less frequent drug
administration.

16. REFERENCE
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delivery system: a review. Int J Phama Res Dev 2011; 2(12): 147-60.
 Bechgaard H, Nielson GH. Controlled release multiple units and single
unit dosage. Drug Dev&Ind Pharm 1978; 4(1): 53-67
 Davis SS, Hardy JG, Taylor MJ, Whalley DR, Wilson CG. Comparative
study of gastrointestinal transit of a pellet and tablet formulation.Int J
Pharm 1984; 21: 167-77.
 Follonier N, Doelkar E. Biopharmaceutical comparison of oral multiple-
unit and single-unit sustained release dosage forms. STP Pharm Sci
1992; 2: 141-58.

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