Determination of parameters for enzyme therapy using L-asparaginase entrapped in canine erythrocytes.
The antitumor agent L-asparaginase was entrapped in canine erythrocytes by a single dialysis encapsulation (efficiency mean = 30%). Concentration of asparaginase in carrier cells was about 240 IU/ml, with an average of 62% cell recovery. Use of a double dialysis procedure increased the L-asparaginase concentration within carrier cells to 530 IU/ml, with an overall cell recovery of 53.9%. In vitro efflux experiments showed L-asparaginase-loaded canine carriers were stable at both 4 and 37 degrees C for an 18-h period. In vivo cell survival studies showed that carrier cells did circulate and that L-asparaginase had a half-life of 6.5 days. No evidence suggesting that the enzyme left the cell was found. Carrier cells prepared with [3H]inulin and [14C]sucrose were stored at 4 degrees C for 2 weeks and began to show signs of deterioration after 2 days.
Naqi
A
A
U.S. Department of Agriculture, College Station, Texas 77841.
DeLoach
J R
JR
Andrews
K
K
Satterfield
W
W
Keeling
M
M
D000818:Animals; D001215:Asparaginase / Q000008:administration & dosage* / Q000276:immunology; D002250:Carbon Radioisotopes; D003956:Dialysis; D004285:Dogs; D004337:Drug Carriers; D017707:Erythrocyte Transfusion; D004912:Erythrocytes / Q000648:ultrastructure; D007444:Inulin / Q000008:administration & dosage / Q000493:pharmacokinetics; D008297:Male; D008855:Microscopy, Electron, Scanning; D012882:Skin Tests; D013395:Sucrose / Q000008:administration & dosage / Q000493:pharmacokinetics; D014316:Tritium
D002250:Carbon Radioisotopes; D004337:Drug Carriers; D014316:Tritium; D013395:Sucrose; D007444:Inulin; D001215:Asparaginase