2. CONTENTS
Introduction
Basic GIT physiology
Process of gastric emptying
Mechanism of FDDS
Approaches for prolonging the gastric residence time
Classification
IMPORTANCE OF FDDS
Factor affecting Floating time
Advantage of FDDS
Disadvantage of FDDS
Evaluation tests
Examples
Conclusion
Reference
1
3. INTRODUCTION
Floating drug delivery systems is known as hydrodynamically controlled
systems.
It is having low bulk density that have sufficiently buoyancy to float over
the gastric contents and remain buoyant (floating) in the Gastric juice of
stomach without affecting the gastric emptying rate for a prolonged
period of time.
This leads to an increased gastric retention time (GRT) and a better control
of the fluctuations in plasma drug concentration.
2
4. BASIC GIT PHYSIOLOGY
• Reservoir for ingested
material.
fundus
• Reservoir for ingested
material.
body
•Major site of mixing motion.
•Acting as pump to propel gastric
contents for gastric emptying.pylorus
3
5. PROCESS OF GASTRIC EMPTYING
Gastric emptying occurs in both fasting and fed states.
Fasting state
Interdigestive
series of electric
event take place.
It cycles both
through stomach
and intestine every
2-3 hrs
It called as
interdigestive
myoelectric cycle
Its having 4 phases
Phase 1
Phase 2
Phase 3
Phase 4
ingestion of a mixed
meal
fed state
(digestive motility
pattern) 4
6. •last from 30-60 minutes with rare
contractions.
Phase 1-(Basic
phase)
•last for 20-40 minutes with
intermittent action potential and
contractions.
Phase 2-
(Preburst
phase)
•last for 10-20 minutes which
includes intense and regular
contractions for short period.
Phase 3-(Burst
phase)
•last for 0-5 minutes and occurs
between phase 2 and 1 of 2
consecutive cycles.Phase 4
5
7. Mechanism of FDDS
• 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
and
g = acceleration due to gravity.
7
8. APPROACHES FOR PROLONGING THE GASTRIC
RESIDENCE TIME
HIGH-DENSITY SYSTEMS. (HDS)
FLOATING SYSTEMS. (FS)
SWELLING AND EXPANDING
SYSTEMS. (SS)
MUCOADHESIVE & BIOADHESIVE
SYSTEMS. (AS)
HDS
FS
SS
8
10. Floating Drug Delivery System
Effervescent
System
Gas generating
system
Volatile liquid/
vacuum containing
system
Non-Effervescent
System
Single Layer
Floating
Tablet
Bilayer
Floating
Tablet
Alginate
Beads
Hollow/
floating
Microspheres
10
11. • Prepared from one or more gel forming or highly swellable
cellulose type hydrocolloids (e.g. hydroxyl ethyl cellulose,
hydroxypropyl methyl cellulose [HPMC] etc ) or polysaccharides,
or matrix forming polymers(e.g polyacrylates, and polystyrene)
are incorporated in high level (20‐75% w/w) to tablets or
capsules.
• Gel forming hydrocolloid swells in contact with gastric fluid after
oral administration and maintain a relative integrity of shape and
bulk density of less than unity within gastric environment.
Non effervescent systems
11
12. Non Effervescent
System
Single Layer Floating Tablet or
hydrodynamically balanced system
Bilayer Floating Tablet
Alginate Beads
Hollow Microspheres/ Microballoons
12
13. HYDRODYNAMICALLY BALANCED SYSYTEMS:
* Prepared by incorporating a high level(20-75%w/w) gel-forming
hydrocolloids. E.g.:- Hydoxyethylcellulose, hydroxypropylcellulose,
Sod. CMC into the formulation and then compressing these granules
into a tablets or capsules
* It maintains the bulk density less than 1.
* The gelatinous polymer barrier formation results from hydrophilic
polymer swelling. 13
14. Bilayered Floating Tablets
These are compressed tablet as containing two layer
1-Immediate release layer
2-Sustained release layer.
14
15. ALGINATE BEADS
- Prepared by dropping sodium alginate solution into aqueous solution of
calcium chloride, causing the precipitation of calcium alginate.
- Freeze dry in liquid nitrogen at -40oc for 24h.
- Beads-spherical and 2.5 mm in diameter.
15
16. HALLOW MICROSPHERES
1. Hallow microspheres as one of the most promising buoyant systems,
as they possess unique advantages of multiple unit systems as well as
better floating properties, because of central hallow spaces inside the
microsphere.
2. The general techniques involved in their preparation include simple
solvent evaporation, and solvent diffusion and evaporation.
16
17. • These are matrix type of systems with the help of swellable polymers
such as methycellulose and chitosan and various effervescent eg, sodium
bicarbonate, tartaric acid and citric acid.
• They are formulated in such a way that when in contact with the acidic
gas content ,CO2 is liberated and gets entrapped in swollen
hydrocolloids, which provides buoyancy to the dosage form.
Effervescent system
17
18. 1. Gas Generating
System
Intra gastric single layer floating
tablet
Intra gastric bilayer floating tablet
Multiple unit floating pills
18
2. Volatile liquid
/vacuum
containing System
Intra gastric floating GIDDS
Inflatable GIDDS
Intra gastric osmotically CDDS
19. Factor affecting Floating time
1
• Effect of Dosage Form Size& Shape
2
• Gender, Posture & Age
3
• Effect of Food & Specific Gravity
4
• Type of Formulation
5
• Nature of Meal & Frequency of Food
19
20. IMPORTANCE OF FDDS
Suitable dosage forms for the drugs those are primarily absorbed in the
stomach.
Beneficial in the treatment of gastric diseases.
Lower dosing and less side effects
The gastric emptying time in humans which normally averages 2-3 hours through the
major absorption zone (stomach and upper part of intestine) can result in incomplete
drug release from the drug delivery system leading to reduced efficacy of administered
dose.
20
21. Advantages of FDDS
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
21
22. Disadvantage of FDDS
The drug substances that are unstable in the acidic environment of the
stomach are not suitable candidates to be incorporated in the systems.
These systems require a high level of fluid in the stomach for drug delivery
to float and work efficiently.
Not suitable for drugs that have solubility or stability problem in GIT.
22
23. EVALUATION TESTS
IN-VITRO TEST IN-VIVO TEST
• Floating lag time
• Floating time
• Dissolution study
• Resultant weight test
• X ray method
• Gamma-scintigraphy
• Gastroscopy
• Ultra sonography
23
24. Marketed Products of GRDDS
Brand name Delivery system Drug (dose) Company
name
Valrelease® Floating capsule Diazepam (15mg) Hoffmann-LaRoche,
USA
Madopar® HBS
(Prolopa® HBS)
Floating, CR capsule Benserazide (25mg) and L-
dopa (100mg)
Roche Products, USA
Liquid Gaviscon® Effervescent Floating
liquid alginate
preparations
Al hydroxide (95 mg), Mg
Carbonate (358 mg)
GlaxoSmithkline,
India
Topalkan® Floating liquid alginate
Preparation
Al – Mg antacid Pierre Fabre Drug,
France
Conviron® Colloidal gel forming
FDDS
Ferrous sulphate Ranbaxy, India
Cytotech® Bilayer floating capsule Misoprostol (100μg/200μg) Pharmacia, USA
Cifran OD® Gas-generating floating
form
Ciprofloxacin (1gm) Ranbaxy, India
24
25. Widely used drug and dosage forms
S
.No Dosage
Form
Drugs
1. MICROSPHERE Aspirin, Griseofulvin, p-nitroglycerine, ibuprofen, Terfinadine,
Tranilast.
2. GRANULES Diclofenac sodium, Indomethacin, Prednisolone
3. FILMS Cinnarizine
4. CAPSULE Chlrdiazepoxide, Diazepam, Furosemide, L-Dopa, Benserazide,
Misoprostol, Propanolol
5. TABLET/ PILLS Acetaminophen, ASA, Amoxicilin Trihydrate,Ampicilin, Atenolol,
Chlorphenarimine,Cinnazirine, Diltiazem,Flourouracil,
Isosorbide Mononitrate & dinitrate, p-aminobenzoic acid,
Prednisolone, Quinidine Gluconate,Ribiflavin 5-p,
Sotalol,Theophylline, Verapamil
25
26. CONCLUSION:
floating drug delivery systems have an efficient
means of enhancing the bioavailability and
controlled delivery of many drugs.
Dosage forms with a prolonged GRT will bring
about new and important therapeutic options
The currently available polymer-mediated Non
effervescent and effervescent FDDS, designed on the basis
of delayed gastric emptying and buoyancy principles,
appear to be a very much effective approach to the
modulation of controlled oral drug delivery.
26
27. REFERENCE
• Controlled drug delivery system concept and advance ,by
S.R.VYAS,196-215
• International Journal of Pharmaceutical Research & Allied
Sciences, Volume 1, issue 4 (2012),20-28
• Journal of Current Pharmaceutical Research 2011 ;7 (1): 6-20
• Pharmacophore International Research Journal 2013, Vol. 4
(1), 26-38
