Drug Delivery Systems
Drug Delivery
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E. Miscellaneous controlled release DDS (Floating DDS)
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Floating drug delivery systems (FDDS) are invented to retain the drug in the stomach, they are applicable for drugs with poor solubility and low stability in intestinal fluids.
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The basis behind FDDS is making the dosage form less dense than the gastric fluids to make it float on them.
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Floating DDS can be used for local action in the G.I.T. as
they are retained in the stomach for a prolonged time due to
their floating property.
Floating tablet
Drug Delivery
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E. Miscellaneous controlled release DDS (Floating DDS)
Classification of FDDS
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Why is FDDS needed
The gastric emptying time in humans which normally averages 2-3hr through the major absorption zone (stomach & upper part of intestine) can result in incomplete drug release from the drug delivery system leading to reduced efficacy of administered dose.
Lower dosing and less side effects.
Beneficial in the treatment of gastric diseases.
Suitable dosage forms for the drugs those are primarily absorbed in the stomach .
E. Miscellaneous controlled release DDS (Floating DDS)
Size of tablet
Density of tablet
Shape of tablet
Viscosity of polymers
Gender
Age
Feeding regimen
Posture
Drug Delivery
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E. Miscellaneous controlled release DDS (Floating DDS)
Simple and conventional technique for formulation.
Site-specific drug delivery.
Controlled delivery of drugs.
Improved drug absorption with increased GRT and excess duration of contact of dosage regimen at its target site (stomach).
Minimizing irritation of GIT mucosa by the drugs with slow release rate.
Used in treating gastroesophageal reflux disorders (GERD).
Ease of administration with higher patient compliance.
Advantages
There are certain situations where gastric retention is not desirable.
Aspirin and non steroidal anti-inflammatory drugs are known to cause gastric lesions, and slow release of such drugs in the stomach is unwanted.
Thus, drugs that may irritate the stomach lining or are unstable in its acidic environment should not be formulated in gastro retentive systems.
Furthermore, other drugs, such as isosorbide dinitrate, that are absorbed equally well throughout the GI tract, drugs undergoing first pass metabolism will not benefit from incorporation into a gastric retention system.
It requires sufficient high level of fluids in the stomach for the drug delivery to float.
The dosage form should be administered with a full glass (200-250 ml).
Disadvantages
Drug Delivery
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E. Miscellaneous controlled release DDS (Floating DDS)
Readily absorption via upper gastrointestinal tract.
Drugs with low pKa
Drugs are possessing lower solubility at higher pH.
Effect of local action of drugs e. g. treating Helicobacter pylori in treatment of ulcerative conditions.
Drugs which get degraded in alkaline pH conditions;
bioavailability of those can be enhanced by fabricating into gastro-retentive forms.
Criteria selection of drug candidate for the floating drug delivery system
