oral controlled drug delivery

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ORAL CONTROLLED DRUG DELIVERYSYSTEMS

Presented by:

SOUMYA MISSULAM.Pharm

Asst. ProfessorNRI College of PharmacyPothavarappadu (V), Agiripalli(M),

Krishna District, A.P,India

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CONTENTS

Introduction

Advantages

Disadvantages

Development of various Novel drug deliverysystems

Conclusion

References

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Oral Controlled Drug Delivery Systems (OCDDS

) is a drug delivery system that

provides continuous oral delivery of drug in a PREDICTABLE &

REPRODUCIBLE KINETICS for a preterm delivery.

ADVANTAGES: Reduction in dosing frequency

Reduced fluctuations in circulating drug levels

Increased patient compliance or acceptance

Avoidance of night time dosing

More uniform effect Reduction in GI irritation and dose-related side effects

DISADVANTAGES:

Highly expensive

Unpredictable and often poor invivo-invitro correlation Dose dumping

Reduced potential for dosage adjustment

Increased potential for first-pass clearance

Poor systematic availability


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Compounds that are unsuitable for design:

Drugs with elimination half-life less than 2 hours

Those drugs that are administered in large doses

Drugs whose therapeutic index is narrow Poorly water-soluble drugs (dissolution-rate limited)

Drugs with long elimination half-life

Drugs which undergo extensive first-pass clearence

Compounds available in controlled release form:

Vitamins

Hormones

Tetracycline

Caffeine

Reserpine

Isosorbide di nitrate Phenobarbital

Aspirin

Aminophylline etc.,


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DEVELOPMENT OF VARIOUS NOVEL DRUG DELIVERY SYSTEMS FOR

ORAL CONTROLLED-RELEASE DRUG ADMINISTRATION:

1. Osmotically controlled-release delivery systems

a.Osmotically controlled DDS with single compartment

b.Osmotically controlled DDS with two compartment

c.Osmotic bursting

d.Hydro dynamic pressure controlled by DDS

2. Membrane permeation controlled delivery systems

a. Microporous membrane permeation

b. Gastric fluid resistant intestine-targeted delivery systems

3. pH controlled delivery systems

4. Ion-exchange delivery systems

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5.Gel Diffusion controlled delivery systems

6. Hydrodynamically Balanced systems

7. Modulation of GI transit time

Swelling systems

Expanding systems

Floating systems

Inflatable systems

Bio(muco)adhesive systems


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1.Osmotically Controlled Release Systems:

Osmotically Controlled Release DDS with single compartment:

Osmotic delivery orifice

Osmotic core containing drug

Semi-permeable membrane



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Rate of drug delivery from orifice is given by..,

(Q/t)z = Pw AM(s-e) SD

hM

Where,

PW = water permeability

AM =Effective surface area

hM = Thickness of membrane

s=Osmotic pressure of Saturated solution of the drug or the salt

c = Osmotic pressure of GI fluidSd = Solubility of the drug

Osmotic Pressure Controlled DDS with 2 compartments

Osmotically active compartment absorbs water from the GI fluid to create

an osmotic pressure.



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Drug delivery through orifice

Semi-permeable coating

Drug reservoir

Movable partition

Osmotically active compartment

Drug release from orifice follows ZERO ORDER KINETICS



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Hydrodynamic Pressure Controlled GI DDS:

Liquiddrug

formulation

Drug delivery orifice

Annular openings

Shape retaining house

SwellSable hydrophilic laminate



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Absorption causes laminate to SWELL & EXPAND which generates

HYDRODYNAMIC PRESSURE in the system.

PUSH-PULL osmotic systems.

2.Membrane permeation Controlled GI DDS:

a.Microporous membrane permeation

TABLET

GI FLUID MICROPOROUS

MEMBRANETABLET



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b. Gastric fluid resistant intestine-targeted delivery systems

Gastric fluid

Liable drug

Gastric fluid

Liable drug

DRUG

GastricemptyingStomach

pH < 3

Intestinal fluid

pH >7.5Insoluble

polymer



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Drug + buffer + excipient

Film forming polymer

3.pH CONTROLLED GI DDS:

Designed for controlled release of ACIDIC or BASIC drugs in GI tract at

rate independent of the variation in GI pH



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DRUG ION exchange resin granules

Polymer coating

Ex: Drug resin complex of phenylpropanolamine administered once every 12 hrs

for 2 weeks.

The rate of drug release is not dependent upon the pH conditions, enzyme

activates and temperature or volume of GIT

The system is administered in the form of large number of particles which may

eliminate the effect of gastric emptying

Can be formulated as a stable liquid suspension type of pharmaceutical dosage

form

4.ION EXCHANGE RESIN SYSTEMS:

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GEL DISFUSSION CONTROLLED GI DDS

COATING LAYER

SEALING LAYER

CROSS-LINKED CMC LAYER

DRUG LOADED CMC LAYER

GEL FORMING SYSTEMS ARE

MULTILAMINATED DEVICES



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HYDRODYNAMICALLY BALANCED SYSTEMS (FLOATING TABLET)

Hydro colloids d 1ColloidalGelbarrier



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7.Modulation of GI transit time:

a) Swelling systems:

they contain either tablets or capsules containing gelatin or reactionproducts of gelatin.

they attain larger size than pylorus.

b) Expanding systems:

It is prepared by compressing medicated polymer layer between two

layers of water insoluble polymer

It is rolled into configuration by gelatin band.



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c) Floating systems:

They contain floating chamber filled with vacuum or harmless air.

The drug reservoir is enclosed inside micro porous compartments

d)Inflatable systems:

Fabricated by loading inflatable chamber with a drug

reservoir, which is impregnated-drug polymeric matrix and then

encapsulated into a capsule.

Floatation chamber

Drug reservoir

aperture



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capsule

Drug reservoir

Inflatable chamber

INFLATABLE SYSTEMS:



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e)Bio (muco) adhesive systems:

The system is coated with muco adhesive polymer which binds with Mucin.

Characters required for the biomucous adhesive polymer:

1.Have molecular flexibility.

2.Should contain hydrophilic functional polymers.

3.Should posses a specific mol.wt, chain length and conformation

Examples:CMC, Carbopol, Tragacanth , HPMC, Acacia, Gelatin, Pectin etc.



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CONCLUSION:

CONTROLLED ORAL DELIVERY provide effective local aswell as systemic drug levels at desirable sites with improved

safety profiles.



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REFERENCES:

NOVEL DRUG DELIVERY SYSTEMS BY Chein

CONTROLLED DRUG DELIVERY By Robinson

www.pubmed.com

www.google.com

.

http://www.pubmed.com/http://www.google.com/http://www.google.com/http://www.pubmed.com/


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