[24] Large-scale entrapment of drugs into resealed red blood cells using a continuous-flow dialysis system

This chapter discusses the large-scale entrapment of drugs into resealed red blood cells, using a continuous-flow dialysis system. The substance to be encapsulated may be introduced (a) before the arrival of the blood into the dialyzer, (b) inside the dialyzer by separating a swelling compartment and a lysing compartment, or (c) at the output of the dialyzer before collecting the lysed cells for resealing. Mode (a) gives better results than mode (c) for a macromolecule as there is no loss of the substance through the dialyzer and the diffusibility seems to be greatest at the lysis step, when the cells are at their point of disruption. Introduction of a macromolecule using mode (c) will reduce the final encapsulation yield, probably because the metastable pores in the membrane already have a reduced size as compared to those at the point of maximum hypotonic swelling of the cells. This method may be easily adapted to the encapsulation of various substances of biological or therapeutic interest, thus leading to potentially efficient drug carriers. The use of a continuous-flow dialysis process may allow development of an extra corporeal circulation for the continuous or semi-continuous transformation of blood from a patient.