2. Resealed Er ythrocyte
As Drug Carrier
BY
S.SHANMUKHA RAJU
PHARMACEUTICS 1ST YEAR II nd semester
256811886011
Under the guidance of
Mr. AJAY KUMAR.V (M.Pharm)
Dept. of Pharmaceutics
KGR INSTITUTE OF TECHNOLOGY
AND MANAGEMENT
3. 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
5. Resealed Erythrocytes
Properties as carrier :-
Appropriate size, shape.
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
6. 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
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. A. Composition of Erythrocytes
Blood contains about 55% of fluid portion(plasma)
45% of corpuscles or formed elements.
Normal blood cells have extensile, elastic ,
biconcave and non nucleated configuration with a
diameter ranging from 6-9 μ and the thickness is
nearly 1-2 μ.
Erythrocytes have a solid content of about 35%
most of which is Hb and rest 65% being water.
Lipid content of erythrocytes includes cholesterol,
lecithin and cephaelins.
9. B. Electrolyte composition of
erythrocytes:
Although qualitatively similar to that of plasma however,
quantitatively it differs from that of plasma.
The concentration of K+ is more in erythrocytes and Na+ in plasma.
The osmotic pressure of the interior of the erythrocytes is equal to
that of the plasma and termed as isotonic (0.9% NaCl or normal
physiological saline.)
Changes in the osmotic pressure of the medium surrounding the red
blood cells changes the morphology of the cells.
10. If the medium is Hypotonic water diffuses into the cells and they get
swelled and eventually loose all their haemoglobin content and may
burst.
And if the medium is hypertonic,(i.e. higher osmotic pressure than
0.9% NaCl) they will shrink and become irregular in shape.
Balanced ion solutions like Ringer’s and Tyrode’s soln. which are not
only isotonic but also contains ions in proper quantity are used in
erythrocyte related experiments.
11. If blood is placed into a tube and
centrifuged, the cells and the plasma will
separate.
The erythrocytes, which are heavy, will
settle down to the bottom of the tube, while
the plasma rises up to the top and the
leukocytes and platelets will form a thin layer
(buffy coat) between the erythrocytes and the
plasma.
The haematocrit is defined as the
percentage of whole blood made up of
erythrocytes.
Males.......... 40-50%
Females....... 38-45%
12. 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)
• Reduce Adverse Effect
• Peptide & Enzyme Delivery
Disadvantages :-
Possibility of Leakage of cells & dose dumping
Molecule Alter Physiology Of cell
13. 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
Different centrifugal force & different buffer composition for different
species is used
Fresh blood is used for loading of drugs.
14. Methods Of Drug Loading In Erythrocytes
Membrane perturbation Electroencapsulation Hypoosmotic lysis Lipid fusion endocytosis
Dilution method Preswell method Osmotic lyses method Dialysis method
15. Dilutional Haemolysis
0.4% NaCl Drug
RBC Membrane ruptured RBC Loaded RBC
Hypotonic Loading buffer
Incubation at Resealing
250c buffer
Hypotonic med
Resealed Loaded RBC
Isotonic med .
Efficiency 1-8% Enzymes
delivery
Washed
16. Isotonic Osmotic Lysis
Physical rupturing
RBC Isotonically ruptured
RBC
Drug Isotonic
Buffer
Chemical
rupturing
Loaded RBC
Incubation at
250 C
Resealed RBC
Chemical – urea, polyethylene, polypropylene, and NH4Cl
17. Preswell Dilutional Haemolysis
5 min incubation Incubation at 25
0.6%w/v NaCl at 0 0c 0
c
Swelled Loaded Resealed
RBC
RBC Drug + Loading RBC RBC
Resealing Buffer
buffer
Efficiency 72%
Fig:- Preswell Method
18. Dialysis
80 %
Haematocrit
value
RBC
Placed in dialysis Dialysis bag placed in 200ml of lysis
+ bag with air bubble buffer with mechanical rotator 2hrs. 4c.
Phosphate
buffer
Loading Drug
buffer
Resealed RBC Dialysis bag placed in Resealing buffer Loaded RBC
with mechanical rotator 30 min 37c.
Efficiency 30-45%
19. Electro-insertion or Electro-
encapsulation
3.7 Kv Current for
2.2 Kv Current for
RBC 20 micro sec
Drug 20 micro sec
+ + Loaded RBC
At 250 C Loading Isotonic NaCl
Pulsation
suspension
medium Resealing Buffer
Resealed RBC
Fig:- Electro-encapsulation Method
20. Entrapment By Endocytosis:-
Buffer containing ATP,
RBC MgCl2, and CaCl2
+ Loaded RBC Resealed RBC
At 250 C
Drug Resealing Buffer
Suspension
Fig;- Entrapment By Endocytos Method
27. Some Important Aspects Of Resealed
Erythrocytes
Mechanism of release of resealed erythrocytes
Shelf & storage stability of resealed erythrocytes
In vivo survival & immunological consequences
28. Storage
Hank’s balance salt solution (HBBS) at 4c for
2 weeks
Oxygenated HBBS containing 1% soft bloom
gelatin
Standard blood bag for both encapsulation and
storage
Cryopreservation of erythrocytes at liquid
nitrogen temp
29. Resent drugs which we can encasulate
A. Antineoplastic drugs:-
1. Actinomycine D
Resent trend:-If encapsulation of Actinomycine D-DNA
is perform,complex is retained in cell for longer time.
2. Methotrexate
3. Bleomycine
4. Doxorubicincine
Resent trend:-RBCs loaded with Doxorubicin HCL
increase half life and bioailability.
5. Etoposide
6. Carboplatin
30. B. ACE Inhibitors:-
Ex:- Enaprilat
C. Anti-Infective agents:-
1. Gentamycine
2. Primaquine
3. Metronidazole
D. Systemic Corticosteroids:-
Ex:- Dexamethasone
E. As a Enzyme carriers:-
1. Alcohole dehydrogenase
2. Aldehyde dehydrogenase
3. Alcohole oxidase
4. L asparginase
5. Uricase
6. Uriase
7. Urokinase
31. 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
32. Applications of resealed erythrocytes
Delivery of antiviral agents
Oxygen deficiency therapy
Microinjection of macromolecules
Novel systems
Nanoerythrosomes
Erythrosomes
33. Recent Developments
Nanoerythrosomes:-
These are small vesicles having size as that of
liposome's. Prepared by extrusion of RBC
ghosts, having average diameter
100nm.Spheroidal,appear to be stable, and
maintain both cytotoxic and antineoplastic
activity.
34. Conclusion
Resealed Erythrocytes is found to be most promising targeted
drug deliery system to Reticuloendothelial system.
Due to non antigenic and non immunogenic nature,it is well
compatable with human immune system.
It is found to be good carrier for various biomolecules like
Enzymes,Peptides etc.
Though use of Resealed Erythrocytes is promising,much area
is found to be unexploerd and technology to develop this
dosage form is not economical which increase the cost of
dosage form.
35. 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.
Indian Journal of Pharmaceutical Education & Research Vol. 43(4),
Oct-Dec, 2009 , 375-386
Journal of Controlled Release 95 (2004) 27– 49
