This presentation discusses using resealed erythrocytes as drug carriers. Erythrocytes are attractive carriers as they are biocompatible and can carry a broad spectrum of drugs while avoiding toxicity. Drugs can be loaded into erythrocytes through hypotonic lysis or endocytosis methods. Loaded erythrocytes are then resealed and characterized. They provide benefits like prolonged drug release and targeting to specific sites. Applications include delivering enzymes, drugs, and targeting the liver or reticuloendothelial system. Resealed erythrocytes show potential as a drug delivery system.

1. Presentation byPresentation by
SUNILBOREDDYSUNILBOREDDY
(M. Pharmacy)(M. Pharmacy)
Resealed ErythrocyteResealed Erythrocyte
As Drug CarrierAs Drug Carrier

2. Content
Introduction
Erythrocytes as drug carrier
Basic concept of erythrocytes
Advantages & limitation
Source & Isolation of Erythrocytes
Method of drug Loading
Characterization
Drug release, Storage
Application
Conclusion

3. 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.

4. 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

5. Erythrocytes
Erythro= red
Cytes = 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
flexibility
Allow them to change shape as
necessary

6. Erythrocytes
CHEMICAL CONSTITUENTS:
Water(63%)
Lipid(0.5%)
Glucose(0.8%)
Minerals(0.7%)
Non-hemoglobin protiens(0.9%)
Methehemoglobin(0.5%) and
Hemoglobin (33.67%)

7. Erythrocytes
Healthy adult male= 4.5 millions/µml
Healthy adult female= 4.8 millions/µml
Matured RBCs have no nucleus Ribosome &
Mitochondria . Therefore all space is available for
drug carrier.
Reticulocytes- immature erythrocytes

8. Advantages of erythrocyte as carrier:-
Biodegradable
Isolation is easy
Non immunogenic
large volume of drug can be encapsulated in small volume of erythrocytes
Prolong systemic activity of drug
Protection from premature degration
Prodrug concept (Bioreactor)
ReduceAdverse Effect
Peptide & Enzyme Delivery
Disadvantages :-
Possibility of Leakage of cells & dose dumping
Molecule Alter Physiology Of cell

9. 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 40
c .
Different centrifugal force & different buffer composition(PBS,pH7.4)
for different species is used
Fresh blood is used for loading of drugs.

10. Methods Of Drug Loading InMethods Of Drug Loading In
ErythrocytesErythrocytes
1. Hypo-osmotic lyses method
a) Dilution method
b) Dialysis method
c) Pre-swell method
d) Isotonic osmotic lyses method
2. Electric breakdown method
3. Endocytosis method
4. Membrane perturbation method
5. Normal transport method
6. Lipid fusion method

11. Dilutional Haemolysis
RBC Membrane ruptured RBC Loaded RBC
Resealed Loaded RBC
0.4% NaCl
Hypotonic
Drug
Loading buffer
Resealing
buffer
Incubation at
250
c
Efficiency  1-8%
Enzymes
delivery
Hypotonic med
Isotonic med.
Washed

12. Isotonic Osmotic Lysis
RBC Isotonically ruptured
RBC
Chemical – urea, polyethylene, polypropylene, and NH4Cl
Physical rupturing
Chemical
rupturing
Drug Isotonic
Buffer
Loaded RBC
Resealed RBC
Incubation at
250
C

13. Preswell Dilutional Haemolysis
RBC
0.6%w/v NaCl Swelled
RBC Drug + Loading
buffer
5 min incubation
at 0 0
c
Loaded
RBC
Incubation at 25
0
c
Resealing Buffer
Resealed
RBC
Efficiency  72%
Fig:- Preswell Method

14. 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%

15. Entrapment by Endocytosis
RBC
Drug
Suspension
+
Buffer containing ATP,
MgCl2, and CaCl2
At 250
C
Loaded RBC Resealing Buffer
Resealed RBC
Fig;- Entrapment By Endocytos Method

16. Membrane perturbation method
RBC
Amphotericin B
e.g. Chemical agents
Increased
permeability of RBC
Resealing Buffer
Drug
Resealed RBC

17. In vitro characterizationIn vitro characterization

18. In vitro characterization

19. Mechanism of release of resealed erythrocytes
Shelf & storage stability of resealed erythrocytes
In vivo survival & immunological consequences
Some Important Aspects Of Resealed
Erythrocytes

20. 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

21. Applications of resealed erythrocytes
Delivery of antiviral agents
Oxygen deficiency therapy
Microinjection of macromolecules
Novel systems
Nanoerythrosomes
Erythrosomes

22. 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.