floating drug delivery system

A SEMINAR A SEMINAR ON ON FLOATING DRUG DELIVERY SYSTEM FLOATING DRUG DELIVERY SYSTEM

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INTRODUCTIONINTRODUCTION

Conventional drug delivery system achieves as Conventional drug delivery system achieves as well as maintain the drug concentration with in well as maintain the drug concentration with in the therapeutically effective range needed for the therapeutically effective range needed for treatment, only when taken several times a day.treatment, only when taken several times a day.

This results in a significant fluctuation in drug This results in a significant fluctuation in drug levels. Recently, several technical levels. Recently, several technical advancements have to the development of advancements have to the development of NDDS that could method of medication and NDDS that could method of medication and provide a number of therapeutic benefits. provide a number of therapeutic benefits.

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OBJECTIVESOBJECTIVES

It would be single, which releases the active It would be single, which releases the active ingredient over an extended period of time.ingredient over an extended period of time.

It should deliver the active entity directly to the It should deliver the active entity directly to the site of action, thus, minimizing or eliminating side site of action, thus, minimizing or eliminating side effects.effects.

Drugs that have narrow absorption window in the Drugs that have narrow absorption window in the GIT will have poor absorption. For these drugs, GIT will have poor absorption. For these drugs, GRDDS offer the advantages in prolonging the GRDDS offer the advantages in prolonging the gastro emptying time. gastro emptying time.

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GASTRO RETENTIVE DRUG GASTRO RETENTIVE DRUG DELIVERY SYSTEMDELIVERY SYSTEM

These are retained in the stomach for a longer These are retained in the stomach for a longer period of time and there by improve the period of time and there by improve the bioavailability of drugs.bioavailability of drugs.

If the drugs are poorly soluble in the intestine If the drugs are poorly soluble in the intestine due to alkaline ph, gastric retention may due to alkaline ph, gastric retention may increase solubility before they are increase solubility before they are emptied,resulting in GIT absorption of drugs with emptied,resulting in GIT absorption of drugs with narrow therapeutic absorption window,as well narrow therapeutic absorption window,as well as,controlling release of drugs having site as,controlling release of drugs having site specific absorption limitation. specific absorption limitation.

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GRDDS

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CONVENTIONAL DRUG CONVENTIONAL DRUG DELIVERY SYSTEMDELIVERY SYSTEM

GASTRORETENTIVE DRUG GASTRORETENTIVE DRUG DELIVERY SYSTEMDELIVERY SYSTEM

High risk of toxicityHigh risk of toxicity Low risk of toxicityLow risk of toxicity

Less patient complianceLess patient compliance Improves patient complianceImproves patient compliance

Not suitable for delivery of drugs Not suitable for delivery of drugs with narrow absorption window with narrow absorption window in small intestine regionin small intestine region

Suitable for delivery of drugs with Suitable for delivery of drugs with narrow absorption window in narrow absorption window in small intestine regionsmall intestine region

Not much advantageous forNot much advantageous for Drugs having rapid absorption Drugs having rapid absorption

through GITthrough GIT Drugs which degrade in the colonDrugs which degrade in the colon Drugs acting locally in the Drugs acting locally in the

stomachstomach Drugs which are poorly soluble at Drugs which are poorly soluble at

an alkaline pHan alkaline pH

Very much advantageous forVery much advantageous forDrugs acting locally in the Drugs acting locally in the

stomach.stomach.Drugs which degrade in the Drugs which degrade in the

colon.colon.Drugs having rapid absorption Drugs having rapid absorption

through GITthrough GIT

No risk of dose dumpingNo risk of dose dumping Possibility of dose dumpingPossibility of dose dumping

CONVENTIONAL V/S GASTRORETENTIVE DRUG DELIVERY SYSTEM

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ADVANTAGESADVANTAGES

SUSTAINED DRUG DELIVERY:SUSTAINED DRUG DELIVERY:

As mentioned earlier drug absorption from oral As mentioned earlier drug absorption from oral control release (CR) Dosage forms is often limited control release (CR) Dosage forms is often limited by the short GRT available for absorption.by the short GRT available for absorption.

These special dosage forms are light, relatively These special dosage forms are light, relatively large in size, and do not easily pass through large in size, and do not easily pass through pylorus, which has an opening of approx 0.1-1.9 pylorus, which has an opening of approx 0.1-1.9 Cms.Cms.

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SITE SPECIFIC DRUG DELIVERY:SITE SPECIFIC DRUG DELIVERY:

A floating dosage form is a feasible approach A floating dosage form is a feasible approach especially for drugs which have limited absorption especially for drugs which have limited absorption sits in upper small intestine.sits in upper small intestine.

The controlled, slow delivery of drug to the stomach The controlled, slow delivery of drug to the stomach provides sufficient local therapeutic levels and limits provides sufficient local therapeutic levels and limits the systemic exposure to the drug.the systemic exposure to the drug.

This reduces side effects that are caused by the This reduces side effects that are caused by the

drug in the blood cerculation.drug in the blood cerculation.

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PHARMACOKINETIC ADVANTAGESPHARMACOKINETIC ADVANTAGES

Drugs that have poor bioavailability because their Drugs that have poor bioavailability because their absorption is limited to upper GI tract can be absorption is limited to upper GI tract can be delivered efficiently thereby maximizing their delivered efficiently thereby maximizing their absorption and improving their absolute bio absorption and improving their absolute bio availabilities.availabilities.

Floating dosage forms with SR characteristics can Floating dosage forms with SR characteristics can also be expected to reduce the variability in transit also be expected to reduce the variability in transit performance. performance.

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LIMITATIONSLIMITATIONS

Floating systems are not feasible for those Floating systems are not feasible for those drugs that have solubility or stability problems drugs that have solubility or stability problems in gastric fluid.in gastric fluid.

They require a sufficiently high level of fluids They require a sufficiently high level of fluids in the stomach for the drug delivery in the stomach for the drug delivery buoyancy, to float there in and to work buoyancy, to float there in and to work efficiently. efficiently.

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APPROACHES TO GASTRIC APPROACHES TO GASTRIC RETENTIONRETENTION

High density approach High density approach

Low density approachLow density approach


MECHANISM OF ACTIONMECHANISM OF ACTION


CLASSIFICATION OF FDDSCLASSIFICATION OF FDDS

Single unit floating dosage systemSingle unit floating dosage system

Effervescent systemEffervescent system

Non - effervescent system Non - effervescent system

Multiple unit floating dosage systemMultiple unit floating dosage system

Effervescent systemEffervescent system

Non – effervescent systemNon – effervescent system

Hollow microspheresHollow microspheres

Raft forming systemRaft forming system


Single unit floating dosage Single unit floating dosage systemsystem

Effervescent system:Effervescent system:

This systems generate gas (COThis systems generate gas (CO22) thus reduce the ) thus reduce the density of the system, and remain buoyant in the density of the system, and remain buoyant in the stomach for a prolonged period of time and release the stomach for a prolonged period of time and release the drug slowly at a desired rate. drug slowly at a desired rate.


Non effervescent system:Non effervescent system:

This systems commonly use gel forming or This systems commonly use gel forming or highly swell able cellulose type hydro colloids, highly swell able cellulose type hydro colloids, polysaccharides and matrix forming polymers polysaccharides and matrix forming polymers such as poly carbonate, poly acrylate, poly such as poly carbonate, poly acrylate, poly methacrylate and poly styrene. methacrylate and poly styrene.


Multiple unit floating system:Multiple unit floating system:

This dosage forms may be an attractive alternate since This dosage forms may be an attractive alternate since they have been shown to reduce inter and intra subject they have been shown to reduce inter and intra subject variability in drug absorption as well as to lower the variability in drug absorption as well as to lower the possibility of dose dumping.possibility of dose dumping.


a)Effervescent system:

Composed of effervescent layers and swell able membrane layers coated on sustained release pills.


b) Non effervescent system:b) Non effervescent system:

A multiple unit HBS containing indo methacin A multiple unit HBS containing indo methacin as a model drug prepared by extrusion as a model drug prepared by extrusion process is reported.process is reported.


Hollow microspheres:Hollow microspheres:

Both natural and synthetic polymers Both natural and synthetic polymers have beenhave been

used to prepare floating microspheres.used to prepare floating microspheres.

Raft forming system:Raft forming system: This systems have received much attention for the This systems have received much attention for the

drug delivery for GI infections and disorders.drug delivery for GI infections and disorders.


EVALUATION OF FDDSEVALUATION OF FDDS

Floating duration Floating duration Dissolution profilesDissolution profiles Specific gravitySpecific gravity Content uniformity Content uniformity Differential scanning calorimetryDifferential scanning calorimetry Particle size analysisParticle size analysis Flow properties Flow properties


APPLICATIONS OF FDDSAPPLICATIONS OF FDDS

Sustained drug delivery Sustained drug delivery

Site specific drug deliverySite specific drug delivery

Absorption EnhancementAbsorption Enhancement


Examples various drugs Examples various drugs formulated as different forms of formulated as different forms of FDDSFDDS

Tablets Theophylline, Furosemide Ciprofolxacin, Pentoxyfillin Captopril, Acetylsalicylic acid

CapsulesNicardipine, Chlordiazepoxide HCl,Diazepam, Propranlol

Microspheres Verapamil, Aspirin, Ketoprofen, Iboprufen

Granules Indomathacin, Prednisolone

Films Drug delivery device, Cinnarizine


Marketed Preparations of Floating Drug Delivery

SystemsS. no Product Active Ingredient

1 Madopar Levodopa and benserzide

2 Valrelease Diazepam

3 Topalkan Aluminum magnesium antacid

4 Almagate flatcoat

Antacid

5 Liquid gavison

Alginic acid and sodium bicarbonate


REFERENCE:REFERENCE:

Chawla G., Gupta P., Koradia V., Bansal A. K., Gastro retention: A means to address regional variability in intestinal drug absorption.

Rouge N., Buri P. & Doelkar E., Drug absorption site in t he gastrointestinal tract tract and dosage forms for site specific delivery. Int.J.Pharm. 1996, 136(1), 117 – 139

Cremer K., Drug delivery: Gastro- remaining dosage forms. Pharm.J. 1997

Grubel P. et al, Gastric emptying of non-digestible solids in the

fasted dog. J.Pharm.Sci. 1987

Garg S., & Sharma S., Gastro retentive drug delivery systems. Drug Delivery oral.2003, 160 – 166.


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