ERYTHROCYTE ENGINEERING FOR DRUG-DELIVERY AND TARGETING

A new procedure for the encapsulation of non-diffusible drugs into hum an erythrocytes was developed. With as little as 50 mi of blood and by using a new apparatus, it was possible to encapsulate a variety of bi ologically active compounds into erythrocytes in 2 h at room temperatu re and under blood-banking conditions. The process, which is based on two sequential hypotonic dilutions of washed red cells followed by con centration with a haemofilter and resealing of red cells, allows a 35- 50% cell recovery and approx. 30% encapsulation of added drugs. The re sulting processed erythrocytes have a normal survival in vivo and can be modified further, with the same apparatus, to increase their recogn ition by tissue macrophages to perform as a drug-targeting system. The new equipment designed and built for this procedure was named 'Red Ce ll Loader'.