This document summarizes a seminar on gastro-retentive drug delivery systems. It introduces the topic and discusses the principles and advantages of gastro-retentive drug delivery. It outlines different drug candidates that can benefit from this system and describes approaches like high density systems, floating systems, and bioadhesive systems. The document concludes that gastro-retentive drug delivery can help control drug release and enhance bioavailability for certain drugs.

1. SEMINAR ON
GASTRO-RETENTIVE DRUG DELIVERY SYSTEM
Presented by: PAWAN DHAMALA
1ST M.PHARM
(Department of pharmaceutics)
Sub: DRUG DELIVERY SYSTEM

2.  INRODUCTION
 PRINCIPLE
 ADVANTAGE
 DISADVANTAGE
 LIMITATION
 APPROACHES
 CONCLUSION
 REFERENCES

3. INTRODUCTION
• Oral drug delivery is widely used in
pharmaceutical field to treat the diseases.
• Some drugs are absorbed at specific site only
,these require release at that specific site.
• Gastro retentive drug delivery(GRDDS) is one
of the site specific drug delivery for the delivery
of the drugs at stomach.
• It is obtained by retaining dosage form into
stomach and drug is being released at
controlled manner at specific site

4. • 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.
Furosamide, Diazepam, Verapamil, etc.
• Drugs with a narrow absorption window. E.g.
Cyclosporine, Levodopa, Methotrexate etc
.

5. GRDDS
• 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

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

7.  Relatively small absorptive surface
area (0.01 sqm vs 100 sq m for GIT).
 Movement affects muco adhesive
systems.
 Less permeable than the small
intestine.
 Salivation and swallowing.
 Taste of the drug.
 Not applicable for unconsciouspatient.

8.  .
• Not suitable for drugs that have
solubility or stability problem in GIT.
• Drugs which are irritant to gastric
mucosa are also not suitable.
• These systems do not offer significant
advantages over the conventional dosage
forms for drugs, which are absorbed
throughout GIT.

9.  Bio-adhesive systems, cannot prevail longer
due to high turn-over rate of mucus layer and
presence of soluble mucin.`
 For swelling systems, it is necessary that the
formulation should not exit before the
appropriates welling.
 For High density systems, High amount of
drug is required.

10. ` • High-density systems. (HDS)
• Floating systems. (FS)
• Swelling and expanding systems.
(SS)
• Mucoadhesive & Bioadhesive
systems. (AS)

11. • Gastro retentive drug delivery systems have
emerged as a current approache of controlled
delivery of drugs that exhibit an absorption
window.
• All these drug delivery systems have their
own advantages and drawbacks.
• To design a successful GRDDS, it is
necessary to take into consideration the
physicochemical properties of the drug,
physiological events in the GIT, formulation
strategies, and correct combination of drug
and excipients.

12.  Hardness Friability
 Drug
 Content
 Diameter
 Weight
 Variation

13.  Evaluation of GRDDS
 Dissolution
 medium : 0.1 N HCl
 Temp. : 37 ± 0.5°C
 RPM : 50-100
 Sample analysis :
 UV
 Dissolution Study

14.  In-vitro
 Mucoadhesion
 Apparatus : USP
 type VI (rotating
 cylinder apparatus)
 Evaluation of GRDDS
 Medium : 0.1 N HCl
 Evaluation of GRDDS
 Temp. : 37 ± 0.5°C
 RPM : 100

15.  Lag time :
 Measurement : 0.1 N HCl at pH 1.2
 Temp. : 37 ± 0.5°C
 Apparatus : USP Type II dissolution
apparatus
 A tablet is placed in a beaker containing
100 –200 ml dissolution medium & the time
for a tablet to emerge on to the surface of the
dissolution medium is known as lag time .

16.  Floating Time
 After achieving lag time, the time taken for a tablet
to remain float on the surface of the dissolution
medium is called floating time.
 Water uptake :
 Apparatus : USP type II dissolution apparatus
 Medium : Water
 Temp. : 37 ± 0.5°C
 RPM : 50
 WU (%) = Wt. of swollen tab. – Initial wt. of tab.
Initial wt. of tab. × 100
 Evaluation of GRDDS