Modified Drug Delivery System.pdf

Modified-release dosage and its variants are mechanisms used in tablets (pills) and capsules to dissolve a drug over time in order to be released more slowly and steadily into the bloodstream, while having the advantage of being taken at less frequent intervals than immediate-release (IR) formulations of the same drug.

1. Presented By
Dr.SaradPawarNaikB
M.Pharm.,Ph.D.,
Associate Professor,
Department of Pharmaceutics & Pharma.Technology,
Kampala International University,
Western Campus, Ishaka

2. Concepts of Drug Delivery
Drugdeliverymeans,atechnologyutilizedtoreleasethedrugatadesired
bodyneed.
Drugdeliverysystemareclassifiedintodifferenttypes...
1.ControlledDrugDeliverySystem
2.SustainedDrugDeliverySystem
3.ModifiedDrugDeliverySystemincludes.,
i.TimedReleaseDDS
ii.ExtendedReleaseDDS
iii.DelayedReleaseDDS

3. 1. Controlled Drug Delivery System
•Controlleddrugdeliverysystemsareconceivedtoreleasedrugina
controlledmannerovertime.Usuallytheaimistoreleasethedrug
overlongperiodsataconstant(zero-order)rate,confinedtothedrug's
therapeuticwindow,althoughinsometherapiesaconstantreleaseisnot
desirable.

4. •Anappropriatelydesignedcontrolled-releasedrugdeliverysystem(CRDDS)
canimprovethetherapeuticefficacyandsafetyofadrugbyprecise
temporalandspatialplacementinthebody,therebyreducingboththesize
andnumberofdosesrequired.
Controlleddrugdelivery-Thisisthedrugdeliverysysteminwhich
aconstantlevelofadrugismaintainedinbloodandtissueforanextended
period.

5. Fig. 1: A hypothetical plasma concentration-time profile from conventional multiple dosing and single
doses of sustained and controlled delivery formulations.
(MSC = maximum safe concentration, MEC = minimum effective concentration)

6. Characteristics of drugs suitable for the controlled release
dosage forms:
Uniform absorption throughout the GIT.
Administered in relatively small doses.
Possess a good margin of safety. For the treatment of
chronic therapy.
Half-life of drug is 3-8 hr,
High aqueous soluble

7. The several advantagesof a controlled drug delivery system over a
conventional dosage form are----
i.Improved patient convenienceand compliance due to less frequent drug
administration.
ii.Reduction in fluctuation in steady-state levels(above figure) and therefore-
Better control of disease condition. And
Reduced intensity oflocal or systemic side-effects.
iii.Maximum utilization of drugenabling reduction in total amount of dose administered.
iv.Reduction in health care coststhrough –
Improved therapy.
Shorter treatment period.
Lower frequency of period.
Reduction in personnel time to dispense, administer and monitor patients.

8. Disadvantages of controlled-release dosage forms include ---
i.Decreasedsystemicavailabilityincomparisonstoimmediatereleaseconventionaldosageforms.
Thismaydueto----
Incompleterelease
Increasedfirst-passmetabolism
Increasedinstability
Insufficientresidencetimeforcompleterelease
Site-specificabsorption
pH-dependentsolubility
ii.Poorinvitro-invivocorrelation
iii.Possibilityofdosedumpingduetofood,physiologicalorformulationvariablesorchewingor
grindingoforalformulationsbythepatientandthus,increasedriskoftoxicity.
iv.Retrievalofdrugisdifficultincaseoftoxicity,poisoningorhypersensitivity
reactions.
v.Highercostofformulation.

9. 2. Sustained Drug Delivery System
INTRODUCTION

11. Advantages of SRDDS (Clinical advantages)
Improvedpatientcompliance
Reductionindruglevelfluctuationinblood
Reductionintotaldrugusagewhencomparedwithconventionaltherapy
Reductionindrugtoxicity(local/systemic)
Improvementinbioavailabilityofsomedrugsbecauseofspatialcontrol
Economicaltothehealthcareprovidersandthepatient

12. Disadvantages of SRDDS
Delayinonsetofdrugaction.
Increasedpotentialforfirstpassmetabolism
Costperunitdoseishigherwhencomparedwithconventionaldoses.
NotalldrugsaresuitableforformulatingintoERdosageform.
PoorInvitro–Invivocorrelation.
Sustained Released Dosage Form: (Nothing but Slowly drug released i.e., Poisons)
Releasedthemedicamentinaportionimmediatelyinordertoachievetherapeutic
levelandtheremainingdosereleasedslowlybyachievingatherapeuticlevelwhichis
prolonged.
(OR)
ItreleasesthemedicamentontheParticularTIME,thenSLOWLLY DECLAIN
ontheConcentration.

13. ADVANTAGES&DISADVANTAGESOfSustainedReleaseDosageForm
Advantages:Zeroorderdeliveryispossible,releaseratesvariablewithpolymertype.
Disadvantages:
Systemmustbephysicallyremovedfromimplantsites.
Difficulttodeliverhighmolecularweightcompound,generallyincreasedcostperdosageunit,
potentialtoxicityifsystemfails.

14. 3. Modified Drug Delivery System
INTRODUCTION
•Theterm“modifiedrelease”referstobothdelayedandextended
releasesystemsfororaladministrationaswellasotherdelivery
systemsdesignedspecificallytomodifythereleaseofpoorly
water-solubledrugs.
•SimpledefinitiontoModifiedreleaseddosageformsarealtered
thetimingandrateofreleaseofdrug.

15. Examples of modified release dosage forms
Systems Examples of drugs
Oral drug products
DiltiazemHCL (extended release)
Diclofenacsodium (delayed release)
Ondansetron(oral soluble film)
Transdermaldrug delivery
system
Clonidine(transdermaltherapeutic
system)
Ophthalmic drug deliveryControlled release pilocarpine

16. Thesearedifferenttypes.
i.ExtendedReleaseDDS-Examples-Controlledrelease,sustainedrelease
andlongactingdrugproducts.
ii.DelayedReleaseDDS-Examples–Entericcoateddosageformslike
entericcoatedaspirin,otherNSAIDS,etc.
iii.RepeatAction-Example-Bi-layeredtablets
iv.TargetAction-Examples:Liposomes,Nanoparticles&Resealed
Erythrocytes

17. TherapeuticAdvantagesofModifiedreleasesystem:
PossibletherapeuticbenefitsofanMRproductincludeimprovedefficacyandr
Rducedadverseevents,
Increasedconvenienceandpatientcompliance,
Optimizedperformance,agreaterselectivityofactivity,ornewindications.