Gastro retentive drug delivery is an approach to prolong gastric residence time. Thereby targeting site-specific drug release in the upper gastrointestinal tract (GIT) for local or systemic effects Gastro-retentive delivery is one of the site specific delivery of the drugs at stomach. It is obtained by retaining dosage form into stomach and drug is being released at sustained manner to specific site either in stomach or intestine.

1. Gastro-retentive drug delivery
system
CSJM UNIVERSITY KANPUR
University Institute of Pharmacy
PRESENTED BY
Manish Kumar
M.Pharm 1st Year
Specialization Pharmaceutics

2. CONTENTS
 Introduction
 Need for GRDDS
 Advantages and Limitations
 Ideal Characteristics for GRDDS
 Types andApproaches of GRDDS
 Marketed Products of GRDDS
 Conclusion
 References

3. INTRODUCTION
 Gastro retentive drug delivery is an approach to prolong gastric
residence time.
 Thereby targeting site-specific drug release in the upper
gastrointestinal tract (GIT) for local or systemic effects
 Gastro-retentive delivery is one of the site specific delivery of the
drugs at stomach.
 It is obtained by retaining dosage form into stomach and drug is
being released at sustained manner to specific site either in stomach
or intestine.

4. o Improve the bioavailability of drugs.
o To overcome physiological adversities
o These are the drug delivery systems which possess the ability of
retaining the drug in the GIT particularly in the stomach for prolonged
period of time.
o Degraded without causing any gastric disturbances.

5. NEED FOR GRDDS
 Conventional oral drug delivery system (DDS) is complicated by
limited gastric residence time (GRT).
 Rapid GI transit can prevent complete drug release in absorption
zone & reduce the efficacy of the administered dose since the
majority of drugs are absorbed in stomach or the upper part of small
intestine.
 To overcome these limitations by various approaches have been
proposed to increase gastric residence of drug delivery systems in the
upper part of GIT includes gastro retentive drug delivery system
(GRDDS).

6. ADVANTAGES
 Enhanced bioavailability
 Sustained drug delivery/reduced frequency of dosing
 Targeted therapy for local ailments in the upper GIT
 Reduced fluctuations of drug concentration
 Improved selectivity in receptor activation
 Reduced counter-activity of the body
 Extended effective concentration.
 Minimized adverse activity at the colon

7. IDEAL CANDIDATES OF DRUG FOR GRDDS
 Drugs acting locally in the stomach.
 E.g.Antacids and drugs for H. Pylori viz.,Misoprostol.
 Drugs that are primarily absorbed in the stomach.
 E.g.Amoxicillin
 Drugs that is poorly soluble at alkaline pH.
 E.g. Furosemide, Diazepam, Verapamil, etc.
 Drugs with a narrow absorption window.
 E.g. Cyclosporine, , Levodopa, Methotrexate etc.
 Drugs which are absorbed rapidly from the GI tract.
 E.g. Metronidazole, tetracycline.
 Drugs that degrade in the colon.
 E.g. Ranitidine, Metformin.
 Drugs that disturb normal colonic microbes.
 E.g. antibiotics against Helicobacter pylori.

8. TYPES AND APPROACHES OF GRDDS

9. HIGH DENSITY SYSTEM
 These have high density than that of gastric fluids[1.4g/cc]
 Zinc oxide , iron oxide, titanium dioxide barium sulphate are used as a
inert heavy core.
 Heavy pellets might Remain
longer in Stomach

10. Floating Drug Delivery Systems.
 FDDS has a bulk density less than gastric fluids and so remain buoyant in the
stomach with out affecting the gastric emptying rate for a prolonged period of time.
 F= F buoyancy-F gravity={Df-Ds}gv
where,
F= total vertical force.
Df= fluid density
Ds=object density
V= volume
G= acceleration due
to gravity.

11. Swelling and expanding system
 The swelling is usually results from osmotic absorption of water.
 The device gradually decreases in volume and rigidity as a result
depletion of drug and expanding agent and/or bioerosion of
polymer layer, enabling its elimination.

12. RAFT FORMING
 This system is used for delivery of
antacids and drug delivery for
treatment of gastrointestinal infections
and disorders.
 The mechanism involved in this
system includes the formation of a
viscous cohesive gel in contact with
gastric fluids, forming a continuous
layer called raft.

13. Evaluation
◦ A. In Vitro Evaluation
a. Floating system
1. Buoyancy lag time
2. Floating time
3. Resultant weight
B. In Vivo Evaluation
1. Radiology
2. Scintigraphy
3. Gastroscopy
4. Magnetic marker monitoring
5. 13C-octanoic acid breath test.

15. CONCLUSION
 Gastro retentive drug delivery systems has proved to be a novel
approach of controlled delivery of drugs that exhibit an absorption
window.
 All these drug delivery systems have their own advantages and
drawbacks.
 From this we can concluded that GRDDS can be a better alternative
than other oral drug delivery system having a retentive drug
delivery system

16. REFERENCES
 S. P.Vyas, Roop K. Khar, CONTROLLED DRUG DELIVERY –
Concepts & Advances, Vallabh Prakashan, page no. 196-217.
 https://www.slideshare.net/UmasankarKrishnamaraju/gastrorentive-
drug-delivery-systems
 N K Jain. Gastroretentive drug delivery
systems Garima Chawla, Piyush Gupta and Aravind K. Bansal
editors. Progress in controlled and novel drug delivery systems.
New Delhi.
,