Linked Life Data

1504072

Source:http://linkedlifedata.com/resource/pubmed/id/1504072

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1992-9-21
pubmed:abstractText
When interacting with phospholipid in an aqueous environment, amphotericin B forms unusual structures of markedly reduced toxicity (Janoff et al. (1988) Proc. Natl. Acad. Sci. USA 85, 6122-6126). These structures, which appear ribbon-like by freeze-fracture electron microscopy (EM), are found exclusively at amphotericin B to lipid mole ratios of 1:3 to 1:1. At lower mole ratios they occur in combination with liposomes. Circular dichroism (CD) spectra revealed two distinct modes of lipid-amphotericin B interaction, one for liposomes and one for the ribbon-like structures. In isolated liposomes, amphotericin B which comprised 3-4 mole percent of the bulk lipid was monomeric and exhibited a hemolytic activity comparable to amphotericin B suspended in deoxycholate. Above 3-4 mole percent amphotericin B, ribbon-like structures emerged and CD spectra indicated drug-lipid complexation. Minimal inhibitory concentrations for Candida albicans of liposomal and complexed amphotericin B were comparable and could be attributed to amphotericin a release as a result of lipid breakdown within the ribbon-like material by a heat labile extracellular yeast product (lipase). Negative stain EM of the ribbon-like structures indicated that the ribbon-like appearance seen by freeze-fracture EM arises as a consequence of the cross-fracturing of what are aggregated, collapsed single lamellar, presumably interdigitated, membranes. Studies examining complexation of amphotericin B with either DMPC or DMPG demonstrated that headgroup interactions played little role in the formation of the ribbon-like structures. With these results we propose that ribbon-like structures result from phase separation of amphotericin B-phospholipid complexes within the phospholipid matrix such that amphotericin B release, and thus acute toxicity, is curtailed. Formation of amphotericin B-lipid structures such as those described here indicates a possible new role for lipid as a stabilizing matrix for drug delivery of lipophilic substances, specifically where a highly ordered packing arrangement between lipid and compound can be achieved.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
1107
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
271-82
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Amphotericin B-phospholipid interactions responsible for reduced mammalian cell toxicity.
pubmed:affiliation
Liposome Company, Inc., Princeton, NJ.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't