In Situ Liposomal Preparation Containing Amphotericin B: Related Toxicity and Tissue Disposition Studies

Abstract

The purpose of this research was to develop a novel hydroalcoholic method for the preparation of liposome entrapping inclusion complex of amphotericin B (AmB) with a view to obtaining reduced toxicity and superior tissue distribution of AmB in vivo. The method involves initial preparation of AmB–hydroxypropyl-β-cyclodextrin (AmB–HPBCD) intercalated proliposome which is subsequently converted into a liposome dispersion by single dilution method. The AmB–liposome (L-AmB) derived from proliposome exhibited a superior entrapment efficiency (94.8 ± 0.7%) compared to liposomes prepared by employing a conventional solvent-based technique (89.7 ± 2.9%). The dose that was lethal to 50% of subjects (LD₅₀) (mg/kg) value of AmB contained in stabilized proliposome-based liposomes was 18.6 ± 0.25, whereas that in conventional solvent-based liposomes was 7.8 ± 0.25. Incorporation of AmB–HPBCD into hydroalcoholic liposomes enhanced antifungal activity in experimental aspergillosis in Balb/c mice in vivo: 80% survival was recorded after 7 days of therapy and the fungal load in lung was reduced. The results clearly demonstrate that preferential uptake of L-AmB entrapped inclusion complex (AmB–HPBCD) by the reticulo endothelial system correlated with diminished levels of AmB in infected (p > 0.05) and noninfected (p > 0.001) kidney after 24 hr compared to that observed with conventional solvent-based L-AmB. Therefore, proliposome-based liposome entrapping inclusion complex of AmB with HPBCD offered an improved therapeutic efficacy by lowering toxicity as well as by altering the tissue distribution pattern.

Keywords:

• Amphotericin B
• Hydroxypropyl-β-cyclodextrin
• Proliposome
• Tissue distribution
• Toxicity