Biodistribution and pharmacokinetics of ¹¹¹In-DTPA-labelled pegylated liposomes after intraperitoneal injection

The biodistribution and pharmacokinetics of ¹¹¹In-DTPA-labelled pegylated liposomes (IDLPL) and unencapsulated ¹¹¹In-DTPA administered by the intraperitoneal (i.p.) and i.v. routes in non-tumour-bearing mice were compared. Mice received i.p. or i.v. injections of 0.37 MBq ¹¹¹In-DTPA either encapsulated in liposomes or as an unencapsulated agent. A variety of tissues were dissected from 5 min to 192 h to determine the biodistribution and pharmacokinetics. Injection of IDLPL via the i.p. route caused a 74-fold increase in the area under the concentration (AUC) versus time curve in the peritoneum compared to unencapsulated ¹¹¹In-DTPA. Similarly, the AUC for all the intra-abdominal tissues was increased significantly (20-427-fold). When i.p. IDLPLs were compared directly with i.v. IDLPLs, more modest changes were seen. There were increases in AUC for peritoneum (1.4-fold), ovary (1.3-fold), stomach (2.9-fold), pancreas (3.6-fold), small intestine (1.5-fold), colon (1.2-fold), gallbladder (5.1-fold) and adrenal gland (2.1-fold). These data support the development of i.p. liposomal chemotherapy for the treatment of intraperitoneal malignant disease.