Approaches Of Gastro-Retentive Drug Delivery System Includes: Floating and Non-Floating drug delivery system with their subtypes Like Non-effervescent system, Effervescent system, Raft forming system, High Density system, Expandable system, Muco-adhesive system, Super porous hydrogel system and Magnetic Systems, etc.

1. Project of Practice School on
“APPROACHES OF GASTRO-RETENTIVE
DRUG DELIVERY SYSTEM”
PRESENTED BY
Mr. Akshay P. Patane
PRN No. 51639020181382310031
UNDER THE GUIDANCE
Ass.Prof. Mr. Junghare S. L.
(M. Pharm in Pharmaceutics)
MERULING SHIKASHAN SANSTHA’S
COLLEGE OF PHARMACY, MEDHA, SATARA.
MAHARASHTRA (INDIA),
YEAR 2021-2022
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2. PRESENTATION OUTLINE
1. Introduction.
2. Approaches of GRDDS.
3. Factors affecting GRDDS.
4. Advantages of GRDDS.
5. Disadvantages of GRDDS.
6. Conclusion.
7. Reference
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3. INTRODUCTION
Oral administration is the most convenient and preferred means of any drug
delivery to the systematic circulation. Oral controlled release drug delivery have
recently been of increasing interest in pharmaceutical field to achieve improved
therapeutic advantages, such as ease of dosing administration, patient compliance and
flexibility in formulation.
The development of oral sustained-controlled release formulations is an attempt
to release the drug slowly into the gastrointestinal tract (GIT) and maintain an
effective drug concentration in the systemic circulation for a long time.
After oral administration, such a drug delivery would be retained in the stomach
and release the drug in a controlled manner, so that the drug could be supplied
continuously to its absorption sites in the gastrointestinal tract (GIT).
The current presentation deals with various gastroretentive approaches that have
recently become leading methodologies in the field of site-specific orally
administered controlled release drug delivery systems.
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4. DIFFERENT APPROACHES OF GRDDS
Floating Drug
Delivery System
Approaches of GRDDS
Non-Floating Drug Delivery
System
Non-Effervescent
System
Effervescent
System
Gas Generating
System
Volatile liquid/Vaccum
System
1.High Density System
2.Expandable System
3.Mucoadhesive System
4.Super porous Hydrogel
5.Magnetic System
Raft
Forming
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5. Floating Drug Delivery System
Floating drug delivery system (FDDS) possess bulk density lower than the gastric fluid and
because of this reason it remains in the stomach without affecting gastric emptying time for an
extended period of time and responsible for controlled release of drug.
(A) Effervescent FDDS
This system made to float in the stomach by incorporating floating chamber, which may be filled
with vacuum, air or inert gas. This system uses matrices prepared with swellable polymer and
effervescent components.
This system is divided in to two classes:
1) volatile liquid containing system 2) gas generating system.
(B) Non- Effervescent FDDS
This system is also known as Hydrodynamically Balanced System (HBS). This system remains
buoyant by entrapment of air in the swelled polymer.
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6. (C) Raft forming system
This system focus more for delivery of antacid and delivery of drugs used to treat gastrointestinal
infection and disorders. The basic mechanism involves formation of viscous cohesive gel when
the system comes in contact with gastric fluid. In this each portion of liquid swells and forms a
continuous layer of gel known as raft. The raft floats because of buoyancy created by formation of
CO2.
Raft Forming System
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7. High Density System
This system possesses a density of about 3 g/cm3 which are retained in the antrum part of the
stomach and are capable of withstanding its peristaltic movements.
This system is prepared by coating a drug on a heavy core or mixed with the inert material
such as iron powder, barium sulphate, zinc oxide and titanium oxide etc. Figure represents high
density system in stomach.
High Density System
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8. Expandable System
This system may be of two types:
1) unfoldable system and 2) swellable polymer.
Swellable systems are retained due to their mechanical property. The swelling is resulted from
absorption of water.
The resultant bulk enables gastric retention and maintains the stomach in the fed condition.
Expandable or swellable System
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9. Mucoadhesive / Bioadhesive System
Mucoadhesion means attachment of the drug to the mucus coat. This approach helps to increase
the gastric residence time of the dosage form by binding them to the gastric mucosa.
Polymers used for this purpose may include polycarbophil, carbopol, CMC, chitosan, lectin etc
Mucoadhesive drug delivery system
Stages of mucoadhesion :
1.Contact Stage
2.Consolidation Stage
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10. Magnetic System
Magnetic System
This approach of increased gastric retention time is based on the principle that dosage form
contains a small internal magnet. A magnet is placed in abdomen over the position of stomach that
retains dosage form in the gastric region.
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11. FACTORS AFFECTING GRDDS
1. Particle size: It should be in the range of 1 – 2 mm to pass through the pyloric
valve into the small intestine.
2. Density: Density of dosage form should less than gastric fluid to float.
3. Size: Size of the system should be in greater than 7.5 mm in diameter.
4. Shape: Ring and tetrahedron shaped system shows better gastric retention
compared with the other shapes.
5. Food intake: Gastric retention time is increased in fed state.
6. Age: Age greater than 70 shows longer residence time.
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12. ADVANTAGES
1. Enhanced bioavailability
2. Sustained drug delivery/reduced frequency of dosing
3. Targeted therapy for local ailments in the upper GIT
4. Reduced fluctuations of drug concentration
5. Site specific drug delivery
DISADVANTAGES
1. Unsuitable for drugs with limited acid solubility. E.g. Phenytoin
2. Unsuitable for drugs that are unstable in acidic environment. E.g. Erythromycin
3. Drugs that irritates or causes gastric lesions on slow release. E.g. Aspirin &
NSAID’s
4. Drugs that absorb selectively in colon. E.g. Corticosteroid
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13. CONCLUSION
Based on the literature survey, it can be concluded that GRDDs offers various
potential advantages for drugs with poor bioavailability. The control of gastro intestinal
transit of orally administered dosage forms using GRDD systems can improve the
bioavailability of drugs that exhibit site specific absorption.
In the future it is can be easily assumed that GRDD systems will become more
popular in terms of delivering drug to the systemic circulation with improving
efficiency of various type of pharmacotherapy’s.
REFERENCE
1.Bhavsar D., Varde N., Shah V., “Advances in Grdds: Raft Forming System a
Review”, Journal of Drug Delivery & Therapeutics; 2(5), 2012, 123-128.
2.Kaur B., Sharma S., Sharma G., Saini R., Singh S, Nagpal M., Jain UK, Sharma M.,
“A Review of Floating Drug Delivery System”, Asian Journal of Biomedical and
Pharmaceutical Sciences, 3(24), 2013, 1-6.
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