COPYRIGHT Gastro-retentive drug delivery system.pdf

GRDDS

1. FORMULATION OF GASTRO RETENTIVE
DRUG DELIVERY SYSTEM
BY: DR. SWATI SANJAY GAIKWAD,
LEENA MANOJ ROKADE,
PALAK RAMESHWAR AGRAWAL.

2. INTRODUCTION:
•A gastro-retentive drug delivery system (GRDDS) is a type of pharmaceutical technology that helps keep a
drug in the stomach or upper gastrointestinal tract for a longer period. This system is designed to ensure
that the medication remains where it can be most effective for an extended time.
•This prolonged retention is used to improve the absorption of drugs that are mainly absorbed in the
stomach or the early parts of the intestine, or to have a local effect right in the stomach.
•This system is especially useful for medications that need to be absorbed in the stomach or the beginning
of the small intestine. It is also beneficial for drugs that might break down or become less effective if
released in the lower parts of the intestines.
•The main goal of GRDDS is to improve the bioavailability and efficacy of medications through controlled
release mechanisms, increased local action, or both.
•The system employs various technologies to maintain the position of the drug within the stomach and to
control its release rate, thereby improving bioavailability, efficacy, and patient compliance.

3. TYPES OF GRDDS:
1.LOW DENSITY OR FLOATING DRUG DELIVERY SYSTEM: Low-density or floating drug delivery systems
are created to float on top of stomach fluids, thus staying in the stomach longer. These systems use
floating agents that either produce gas or are naturally lightweight. Floating drug delivery systems
(FDDS) can be achieved through two main systems:
•Effervescent system: This includes gas-generating agents like sodium bicarbonate or citric acid.
When these agents come into contact with stomach fluids, they react to form carbon dioxide gas. This
gas forms bubbles that make the dosage form buoyant, allowing it to float on the stomach's contents.
•Non-Effervescent Systems: These systems incorporate low-density materials or matrices that are less
dense than gastric fluids, allowing them to float on the gastric content. They may include
hydrocolloids, such as hydroxypropyl methylcellulose (HPMC), or other polymers that provide
buoyancy without relying on gas generation.

4. 2.HIGH DENSITY OR NON FLOATING DRUG DELIVERY SYSTEM: These systems are designed to stay in the stomach
longer by using heavy materials. These systems work by settling at the bottom of the stomach, which stops them
from moving into the small intestine too quickly. This method uses materials that are denser than the fluids in the
stomach, such as barium sulfate, zinc oxide, or calcium carbonate, to achieve this effect.

3.MUCOADHESIVE OR GASTRO-ADHESIVE DRUG DELIVERY SYSTEM: Mucoadhesive or gastro-adhesive drug
delivery systems are designed to stick to the mucosal surfaces inside the body, like those in the gastrointestinal
tract. These systems use bio-adhesive polymers, which are sticky materials that can attach to the mucosal lining.
Some common polymers used include cellulose derivatives (such as hydroxypropyl methylcellulose and
carboxymethyl cellulose), chitosan, and poly(acrylic acid) derivatives. These materials help keep the drug delivery
device in place for a longer time, allowing for prolonged drug action at the site of application.

4.SUPER-POROUS HYDROGEL SYSTEM: Super-porous hydrogels are highly porous materials that swell rapidly in
gastric fluids, forming a large structure that traps drugs and prolongs their stay in the stomach. In the context of
GRDDS, super-porous hydrogels are formulated into drug delivery devices, such as tablets or capsules, that rapidly
swell upon contact with gastric fluids. This rapid swelling leads to the formation of a large, porous structure
within the hydrogel, which traps the drug dosage form and prevents its passage through the pyloric sphincter into
the small intestine.

5. 5.MAGNETIC SYSTEM: Magnetic systems in gastro-retentive drug delivery are designed to prolong gastric retention
by utilizing external magnetic fields to control the movement and position of drug delivery devices within the
gastrointestinal tract. These systems typically incorporate magnetic materials, such as iron oxide nanoparticles,
into the drug formulation or dosage form.

6.OSMOTICALLY CONTROLLED SYSTEM: This gastro-retentive drug delivery use osmotic pressure to regulate drug
release. They consist of a drug core surrounded by a semipermeable membrane. When in contact with gastric
fluids, water enters the system, creating pressure that pushes the drug out through a pore in the membrane,
ensuring controlled release over time.

7.MODIFIED SHAPE OR UNFOLDING SYSTEM: Modified shape or unfolding systems in gastro-retentive drug
delivery are formulations that change shape or size in response to gastrointestinal conditions, prolonging gastric
retention and enhancing drug absorption. They may expand or unfold upon contact with gastric fluids, ensuring
controlled release and improved therapeutic outcomes for drugs with specific absorption needs.

6. EXCIPIENTS USED IN GRDDS:
•Excipients used in gastro-retentive drug delivery systems (GRDDS) play critical roles in formulation
development, ensuring the desired properties such as buoyancy, muco-adhesion, controlled release, and
stability. Some common excipients used in GRDDS include:
1.Polymeric Materials:
i.Hydroxypropyl methylcellulose (HPMC)
ii.Ethylcellulose
iii.Methylcellulose
2.Buoyancy Enhancers:
i.Calcium carbonate
ii.Magnesium carbonate
iv.Sodium carboxymethylcellulose (NaCMC)
v.Chitosan
vi.Polyethylene oxide (PEO)

iii.Sodium bicarbonate
iv.Citric acid

7. 3.Gelling Agents:
i.Carbomer
ii.Xanthan gum

iii.Guar gum
iv.Gelatin
4.Osmotic Agents:
i.Sodium chloride
ii.Mannitol

iii.Lactose
iv.Sorbitol
5.Disintegrants:
i.Crospovidone
ii.Croscarmellose sodium

iii.Sodium starch glycolate

6.Plasticizers:
i.Glycerin
ii.Propylene glycol

iii.Polyethylene glycol (PEG)

7.Fillers and Diluents:
i.Microcrystalline cellulose
ii.Lactose

iii.Calcium phosphate
8.Coating Materials:
i.Ethylcellulose
ii.Eudragit polymers

iii.Shellac
iv.Acrylic polymers

8. ADVANTAGES AND DISADVANTAGES:
ADVANTAGES:
i.Prolonged Gastric Retention
ii.Enhanced Drug Absorption
iii.Improved Bioavailability
iv.Controlled Drug Release
v.Targeted Drug Delivery
vi.Minimized Side Effects
vii.Enhanced Therapeutic Outcomes
viii.Reduced Dosage Frequency

DISADVANTAGES:
i.Gastric Irritation
ii.Gastrointestinal Obstruction
iii.Food Interactions
iv.Limited Drug Compatibility
v.Risk of Incomplete Gastric Emptying
vi.Difficulty in Swallowing

9. APPLICATION:
•Improved Patient Compliance
•Local Treatment of Gastrointestinal Disorders
•Enhanced Bioavailability
•Treatment of Gastric Ulcers and Gastroesophageal Reflux Disease (GERD)
•Localized Drug Delivery
•Treatment of Motion Sickness
•Prevention and Treatment of Gastric Mucosal Injury