Surface modified methotrexate loaded erythrocytes for enhanced macrophage uptake

The unique property of macrophages to distinguish between 'mature self' and 'senescent self' was applied for the enhanced macrophage uptake upon loadi ng drugs into erythrocytes and provoking environment within which it gets t ranslated into senescent cells. Two different approaches were applied one b y depleting the sialic acid from the surface of cells and another by induci ng hemichrome formation in the cells. Erythrocytes encapsulation of methotr exate was carried out by preswell dilution technique. Surface modification of erythrocytes was performed using desialation and hemichrome induction by treating with trypsin (Tt) and phenylhydrazine (PhT) respectively. Desiala tion technique was optimized in terms of concentration of trypsin, incubati on temperature and time period. Both of these surface modified erythrocytes were characterized for in vitro macrophage uptake. In vivo organ localizat ion was assessed by recording amount of drug present in different organs. T he macrophage uptake of both surface modified erythrocytes was enhanced by almost 3-5 and 5-6 times with Tt and PhT cells, respectively. These new sur face modified carriers are found to be excellent candidate for enhanced mac rophage uptake and anticipated to be useful for any RES tumors.