Biodistribution and pharmacokinetics of111In-DTPA-labelled pegylated liposomes in a human tumour xenograft model: implications for novel targeting strategies

The biodistribution and pharmacokinetics of111In-DTPA-labelled pegylated liposomes in tumour-bearing nude mice was studied to examine possible applications of pegylated liposome-targeted anti-cancer therapies. Nude mice received an intravenous injection of 100 μl of111In-DTPA-labelled pegylated liposomes, containing 0.37–0.74 MBq of activity. The t 1/2α and t 1/2β of111In-DTPA-labelled pegylated liposomes were 1.1 and 10.3 h, respectively. Tumour uptake was maximal at 24 h at 5.5 ± 3.0% ID g–1. Significant reticuloendothelial system uptake was demonstrated with 19.3 ± 2.8 and 18.8 ± 4.2% ID g–1at 24 h in the liver and spleen, respectively. Other sites of appreciable deposition were the kidney, skin, female reproductive tract and to a lesser extent the gastrointestinal tract. There was no indication of cumulative deposition of pegylated liposomes in the lung, central nervous system, musculoskeletal system, heart or adrenal glands. In contrast, the t 1/2α and t 1/2β of unencapsulated111In-DTPA were 5 min and 1.1 h, respectively, with no evidence of accumulation in tumour or normal tissues. Incubation of111In-DTPA-labelled pegylated liposomes in human serum for up to 10 days confirmed that they are very stable, with only minor leakage of their contents. The potential applications of pegylated liposomes in the arena of targeted therapy of solid cancers are discussed. © 2000 Cancer Research Campaig

Influence of tumour size on uptake of111In-DTPA-labelled pegylated liposomes in a human tumour xenograft model

The relationship between tumour size and uptake of111In-DTPA-labelled pegylated liposomes has been examined in a human head and neck cancer xenograft model in nude mice. The mean tumour uptake of111In-labelled pegylated liposomes at 24 hours was 7.2 ± 6.6% ID/g. Liposome uptake for tumours < 0.1 g, 0.1–1.0 g and > 1.0 g was 15.1 ± 10.8, 5.9 ± 2.2 and 3.0 ± 1.3% ID/g, respectively. An inverse correlation between tumour weight and liposome uptake was observed by both Spearman’s rank correlation test (r s= – 0.573, P< 0.001) and Pearson’s correlation coefficient (r s= – 0.555, P< 0.001). For 18 tumours with macroscopic central necrosis, the ratio of uptake in the tumour rim relative to the necrotic tumour core was 11.2 ± 6.4. Measurement of tumour vascular volume for tumours of various sizes revealed an inverse correlation between tumour weight and tumour vascular volume (Spearman’s rank correlation test, r s= – 0.598, P< 0.001), consistent with poor or heterogeneous vascularization of larger tumours. These data have important implications for the clinical application of pegylated liposome targeted strategies for solid cancers which are discussed in detail. © 2000 Cancer Research Campaig

Cationic polyelectrolytes: A new look at their possible roles as opsonins, as stimulators of respiratory burst in leukocytes, in bacteriolysis, and as modulators of immune-complex diseases (A review hypothesis)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44497/1/10753_2004_Article_BF00915991.pd

Enlarged parietal foramina: findings on prenatal ultrasound and magnetic resonance imaging

Letter to the Editorlink_to_OA_fulltex

Insertion of poly(ethylene glycol) derivatized phospholipid into pre-formed liposomes results in prolonged in vivo circulation time

AbstractTransfer of MPEG1900-DSPE from micellar phase to pre-formed liposomes imparts long in vivo circulation half-life to an otherwise rapidly cleared lipid composition. MPEG1900-DSPE transfers efficiently and quickly in a time and temperature dependent manner. There is negligible content leakage and a strong correlation between assayed mol% MPEG1900-DSPE, liposome diameter increase, and pharmacokinetic parameters such as distribution phase half-life. Since a biological attribute (liposome clearance rate) can be modified by the insertion process, it suggests a simple and economical way to impart site-specific targeting to a variety of liposome delivery systems. This method is also a convenient way to measure the ‘brush’ thickness of such conjugates directly

Zur Theorie verallgemeinerter Koethescher Folgen- und Funktionenraeume

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman