Presenting By: MAHESWARI.G

Guided By: Prof. Mrs. A .PRAMEELA RANI GARU M. Pharm , Ph.D

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

Introduction:-

DEF: They are drug -loaded carrier erythrocytes

Idea of drug carrier system

Magic Bullet Concept by PAUL ERLICH

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

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

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

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.

Membrane perturbation Electroencapsulation Hypoosmotic lysis Lipid fusion endocytosis

Dilution method Preswell method Osmotic lyses method Dialysis method

Dilutional Haemolysis

RBC Membrane ruptured RBC Loaded RBC

Resealed Loaded RBC

0.4% NaCl

Hypotonic

Drug

Loading buffer

Resealing buffer

Incubation at 250c

Enzymes delivery

Hypotonic med

Isotonic med.

Washed

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

Preswell Dilutional Haemolysis

RBC 0.6%w/v NaCl Swelled

RBC Drug + Loading buffer

5 min incubation at 0 0c

Loaded

RBC

Incubation at 25 0c

Resealing Buffer

Resealed

RBC

Fig:- Preswell Method

Dialysis

RBC

Phosphate buffer

+ 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

Electro-insertion or Electro-encapsulation

RBC 2.2 Kv Current for 20 micro sec

At 250 CPulsation medium

+ +Drug

Loading suspension

3.7 Kv Current for 20 micro sec

Isotonic NaClLoaded RBC

Resealing Buffer

Resealed RBC

Fig:- Electro-encapsulation Method

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

Membrane perturbation method

RBCAmphotericin B

e.g. Chemical agents

Increased permeability of RBC

Resealing Buffer

Drug

Resealed RBC

Advantages :-Biodegradable & biocompatibleIsolation is easy Non immunogenic

large volume of drug can be encapsulated in small volume of erythrocytesProlong systemic activity of drug

Protection from premature degradation Prodrug concept (Bioreactor) Reduce Adverse Effect Peptide & Enzyme Delivery Disadvantages :-

Possibility of Leakage of cells & dose dumping Molecule Alter Physiology Of cell

Applications of resealed erythrocytesErythrocytes 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

Applications of resealed erythrocytes

Delivery of antiviral agentsOxygen deficiency therapyMicroinjection of macromolecules

Novel systems Nanoerythrosomes Erythrosomes

CONCLUSION:-The use of resealed erythrocytes looks promising for a safe and sure delivery of various drugs for passive and active targeting. However, the concept needs further optimization to become a routine drug delivery and much remains to be explored regarding the potential of resealed erythrocytes

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.

PHARMACEUTICAL TECHNOLOGY : A Review