Presented by. Atif Ali

ErythrocytesAs Drug Carriers

Presentation by

Atif Ali

Content • Introduction • Erythrocytes as drug carriers • Basic concept of erythrocytes• Advantages & limitations• Source & Isolation of Erythrocytes• Methods of drug Loading • Characterization• Drug release, Storage • Applications• Conclusion

ErythrocytesProperties 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

Erythrocytes • Erythro= red• Cytes = cells

• Biconcave discs, anucleate.• Filled with hemoglobin

(Hb), a protein that functions in oxgen transport

• Contain the plasma membrane protein and other proteins that:– Give erythrocytes their

flexibility– Allow them to change shape

as necessary

Erythrocytes

Healthy adult male= 5.4 millions cells/mm 3Healthy adult female= 4.8 millions cells/mm 3

Matured RBCs have no nucleus Ribosome & Mitochondria . Therefore all space is available for drug carrier.

Reticulocytes- immature erythrocytes

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• Reduce Adverse Effect• Peptide & Enzyme Delivery

limitations :-Possibility of Leakage of cells & dose dumping

Molecule Alter Physiology Of cell

Source, fractionation & isolation of erythrocytes

Source:- mice, cattle, pig, dog, sheep, goat, monkey, chicken, rat, rabbit & human

Whole blood can be collected by venipuncture 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 method

RBCAmphotericin B

e.g. Chemical agents

Increased permeability of RBC

Resealing Buffer

Drug

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:-

RBCDrug

Suspension+

Buffer containing ATP, MgCl2, and CaCl2

At 250 CLoaded RBC

Resealing Buffer

Resealed RBC

Fig;- Entrapment By Endocytos Method

Hypotonic Dilution

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

Hypotonic Preswelling

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

Efficiency 72%

Fi:- Preswell Method

In vitro characterization

In vitro characterization

• Mechanism of release of resealed erythrocytes

• Shelf & storage stability of resealed erythrocytes

Some Important Aspects Of Resealed Erythrocytes

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

Applications of resealed erythrocytes

Delivery of antiviral agentsOxygen deficiency therapy