Application of oligo-(14-amino-3,6,9,12-tetraoxatetradecanoic acid) lipid conjugates as steric barrier molecules in liposomal formulations.

Important note: Information in this article was accurate in 1999. The state of the art may have changed since the publication date.

Application of oligo-(14-amino-3,6,9,12-tetraoxatetradecanoic acid) lipid conjugates as steric barrier molecules in liposomal formulations.

Bioconjug Chem. 1999 Jul-Aug;10(4):653-66. Unique Identifier : AIDSLINE MED/99339826
Ansell SM; Kojic LD; Hankins JS; Sekirov L; Boey A; Lee DK; Bennett AR; Klimuk SK; Harasym TO; Santos ND; Semple SC; Inex Pharmaceuticals Corp., 100-8900 Glenlyon Parkway, Burnaby,; B.C., V5J 5J8, Canada. sansell@inexpharm.com

Abstract: Lipid conjugates of oligo-(14-amino-3,6,9,12-tetraoxatetradecanoic acid) (ATTAn) were synthesized as monodisperse analogues of poly(ethylene glycol) (PEG) derivatives used in liposomal drug delivery systems. The new lipids were shown to be at least equivalent to MePEGA-2000-DSPE in assays designed to evaluate the effectiveness of polymers as steric barrier molecules in liposomes. Liposomes containing 1-5% of ATTA8-DSPE (octamer) showed comparable long circulation behavior relative to PEG-2000-DSPE analogues. Surprisingly, the shorter ATTA4-DSPE (tetramer) appeared to be quite effective in reducing clearance. Liver enzyme levels and systemic single dose tolerability of ATTA8-DSPE liposomes were comparable to controls, suggesting that the new materials are nontoxic. Prolonged exposure of ATTA8-DSPE liposomes to splenocytes in vitro showed no evidence of mitogenicity relative to controls or MePEGA-2000-DSPE liposomes. ATTA8-DSPE was as effective as MePEGC-2000-DSPE in preventing complement activation by cationic liposome systems. Repeat dosage in vivo regimes in ICR mice using DSPC/cholesterol liposomes, with and without 5% ATTA8-DSPE and MePEGC-2000-DSPE, showed no evidence of enhanced clearance on successive doses. Splenocytes recovered after repeat doses showed no significant evidence of mitogenicity on restimulation with liposomes. Cellular differentiation and activation marker levels in splenocytes recovered after the fourth in vivo administration were at normal levels. These results suggest that ATTAn oligomers do not induce an immune response in isolation. It was demonstrated that ATTA8-DSPE could be used to replace PEG-lipids in the formulation of doxorubicin, plasmid DNA and oligonucleotides using a variety of formulation techniques. The study demonstrates that ATTAn oligomers can be safely and effectively used in place of poly(ethylene glycol) as well-defined biomaterials in liposomal applications where reproducible behavior is critical.

Keywords: JOURNAL ARTICLE Animal Antibiotics, Anthracycline/ADMINISTRATION & DOSAGE Complement Activation/DRUG EFFECTS Cytokines/CHEMISTRY Doxorubicin/ADMINISTRATION & DOSAGE Drug Carriers/CHEMISTRY Enzyme-Linked Immunosorbent Assay Female Fluorescent Dyes/CHEMISTRY Indicators and Reagents Lipids/*CHEMISTRY Liposomes/*CHEMISTRY Mice Mice, Inbred BALB C Mitogens/TOXICITY Myristic Acids/*CHEMISTRY/TOXICITY Oligonucleotides, Antisense/CHEMISTRY Pharmaceutic Aids/CHEMISTRY Phenotype Polyethylene Glycols/CHEMISTRY
991230
A99C1048

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