Resealed erythrocytes
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Presentation byPresentation by SUNILBOREDDY SUNILBOREDDY
(M. Pharmacy)(M. Pharmacy)
Resealed ErythrocyteResealed ErythrocyteAs Drug CarrierAs Drug Carrier
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Content Introduction Erythrocytes as drug carrier Basic concept of erythrocytesAdvantages & limitationSource & Isolation of ErythrocytesMethod of drug Loading CharacterizationDrug release, Storage Application Conclusion
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INTRODUCTION
Current Research: Aimed at development of drug delivery system to get max. therapeutic effect.
Idea of drug carrier system: to get maximum therapeutic effects, Elimination of undesirable side effects and Increase patient compliance.
Magic Bullet Concept: Paul Ehrlich proposed. Decrease toxic effect and increase therapeutic effect to the targeted cell.
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Resealed Erythrocytes
Properties as carrier :- Appropriate size, shape to permit passage
through the capillaries. Biocompatible & minimum toxic side effects Minimum leakage before target site is
achieved Should be able to carry broad spectrum of
drugs Appreciable stability during storage period Should have sufficient space & should carry
adequate amounts of drugs
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Erythrocytes Erythro= redCytes = cell
Biconcave discs, anucleate.
Filled with hemoglobin (Hb), a protein that functions in gas transport
Contain the plasma membrane protein spectrin and other proteins that:Give erythrocytes their
flexibilityAllow them to change
shape as necessary
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ErythrocytesCHEMICAL CONSTITUENTS:Water(63%)Lipid(0.5%)Glucose(0.8%)Minerals(0.7%)Non-hemoglobin protiens(0.9%)Methehemoglobin(0.5%) and Hemoglobin (33.67%)
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Erythrocytes
Healthy adult male= 4.5 millions/µmlHealthy adult female= 4.8 millions/µml
Matured RBCs have no nucleus Ribosome & Mitochondria . Therefore all space is available for drug carrier.
Reticulocytes- immature erythrocytes
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Advantages of erythrocyte as carrier:-Biodegradable Isolation is easy Non immunogenic
large volume of drug can be encapsulated in small volume of erythrocytesProlong systemic activity of drug
Protection from premature degration Prodrug concept (Bioreactor) Reduce Adverse Effect Peptide & Enzyme Delivery
Disadvantages :-Possibility of Leakage of cells & dose dumping
Molecule Alter Physiology Of cell
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Source, fractionation & isolation of erythrocytes
Source:- mice, cattle, pig, dog, sheep, goat, monkey, chicken, rat, rabbit & human
Whole blood can be collected by venipuncture or from orbital sinus in heparinized tube
Red blood cells can be harvested & centrifuged(2500rpm/5min at 40c .
Different centrifugal force & different buffer composition(PBS,pH7.4) for different species is used
Fresh blood is used for loading of drugs.
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Methods Of Drug Loading In Methods Of Drug Loading In ErythrocytesErythrocytes1. Hypo-osmotic lyses method a) Dilution method b) Dialysis method c) Pre-swell method d) Isotonic osmotic lyses
method2. Electric breakdown method3. Endocytosis method4. Membrane perturbation method5. Normal transport method6. Lipid fusion method
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Dilutional Haemolysis
RBC Membrane ruptured RBC Loaded RBC
Resealed Loaded RBC
0.4% NaCl
Hypotonic
Drug
Loading buffer
Resealing buffer
Incubation at 250c
Efficiency 1-8%Enzymes delivery
Hypotonic med
Isotonic med.
Washed
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Isotonic Osmotic Lysis
RBC Isotonically ruptured
RBC
Chemical – urea, polyethylene, polypropylene, and NH4Cl
Physical rupturing
Chemicalrupturing
Drug IsotonicBuffer
Loaded RBC
Resealed RBC
Incubation at 250 C
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Preswell Dilutional Haemolysis
RBC0.6%w/v NaCl Swelled
RBC Drug + Loading buffer
5 min incubation at 0 0c
Loaded
RBC
Incubation at 25 0c
Resealing Buffer
Resealed
RBC
Efficiency 72%
Fig:- Preswell Method
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Dialysis
RBC
Phosphate buffer
+
80 % Haematocri
t value
Placed in dialysis bag with air bubble
Dialysis bag placed in 200ml of lysis buffer with mechanical rotator 2hrs. 4c.
DrugLoading buffer
Loaded RBCDialysis bag placed in Resealing buffer with mechanical rotator 30 min 37c.
Resealed RBC
Efficiency 30-45%
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Entrapment by Endocytosis
RBC
Drug Suspension
+Buffer containing
ATP, MgCl2, and CaCl2
At 250 CLoaded RBC Resealing Buffer Resealed RBC
Fig;- Entrapment By Endocytos Method
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Membrane perturbation method
RBC
Amphotericin B
e.g. Chemical agents
Increased
permeability of RBCResealing Buffer
Drug
Resealed RBC
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In vitro In vitro characterizationcharacterization
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In vitro characterization
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Mechanism of release of resealed erythrocytes
Shelf & storage stability of resealed erythrocytes
In vivo survival & immunological consequences
Some Important Aspects Of Resealed Erythrocytes
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Applications of resealed erythrocytes
Erythrocytes as carrier for enzymes
Erythrocytes as carrier for drugs
Erythrocytes for drug targeting Drug targeting to reticuloendothelial system
Drug targeting to liver
-Treatment of liver tumors-Treatment of parasitic diseases-Removal of RES iron overload-Removal of toxic agents
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Applications of resealed erythrocytes
Delivery of antiviral agentsOxygen deficiency therapyMicroinjection of macromolecules
Novel systemsNanoerythrosomesErythrosomes
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References
Jain.S., Jain.N.K., resealed erythrocytes as drug carriers, Edited Jain N.K., Controlled And Novel Drug Delivery, New Delhi, CBS publishers, New Delhi, 2004, 256-281.
Vyas S.P., Khar R.K., Targeted And Controlled Drug Delivery: Novel Carrier Systems, New Delhi, CBS publisher, 2004, 387-413.
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