INFLUENCE OF SIZE OF LIPOSOMES IN POTENTIATING THE EFFICACY OF ENCAPSULATED TRIETHYLENETETRAMINE-HEXAACETIC ACID (TTHA) AGAINST CADMIUM INTOXICATION

Polyaminocarboxylic acids have widely been used as antidotes in heavy metal intoxication, however their hydrophilic nature renders them to b e mostly distributed extracellularly. To facilitate the intracellular delivery of such chelating agent, triethlene-tetraamine-hexaacetic aci d (TTHA) was encapsulated in small unilamellar vesicles (SUV) or dehyd ration rehydration vesicles (DRV) and its effect was examined in the a melioration of cadmium toxicity. Mice were administered cadmium (0.2 m g/kg B.wt.) as CdCl2 intraperitoneally daily for five days. After a pe riod of four weeks rest. they were given two intravenous injections of TTHA as free material or encapsulated in liposomes (0.16 m mole/kg) a t a gap of 48 hours. Urinary and fecal elimination of cadmium and its distribution in the liver, kidney and spleen was monitored after TTHA treatment. The results indicate the efficacy of TTHA in removing cadmi um from the body organs of preexposed animals and its excretion throug h urine and feces was maximum when it was encapsulated in SUV liposome s.