Document Detail


Fluorocarbon emulsions--the stability issue.
MedLine Citation:
PMID:  7849970     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Long-term room temperature stability of ready-to-use concentrated fluorocarbon emulsions is necessary in order to fully exploit the therapeutic potential of fluorocarbons. Consequently, considerable efforts have been directed at investigating the physical nature of such emulsions, the mechanisms which lead to their degradation and the means of counteracting these. The particles which constitute typical fluorocarbon/egg yolk phospholipid emulsions have been identified to be surfactant-coated fluorocarbon droplets and lipid vesicles. Better understanding has been gained on the formation, structure and evolution of these particles during processing and storage. This has led to optimized formulations and processing, better control of emulsion characteristics and significantly improved stability. Molecular diffusion (Ostwald ripening or transcondensation) has been shown to be the maun mechanism of degradation when particles are less than 1 micron in diameter, even for the highly concentrated (volume fraction of fluorocarbon up to 50%) second generation fluorocarbon emulsions. Significant emulsion stabilization has been accomplished by adding fluorochemicals which are both less volatile and less water soluble, and nevertheless have an organ dwell time acceptable for intravascular use. The rate of molecular diffusion can also be reduced by decreasing the fluorocarbon/water interfacial tension; this was effectively achieved with appropriate, well-defined fluorinated surfactants. A further, novel means of stabilizing fluorocarbon-in-water emulsions makes use of mixed fluorocarbon-hydrocarbon amphiphiles which act as molecular dowels to reinforce the adhesion between the fluorocarbon phase and the lipophilic zone of the surfactant film. Both long-term room temperature stability, and particle-size control over a large range of diameter, have been achieved by applying this principle. All in all it can be said that the challenge of producing injectable fluorocarbon emulsions with long-term room temperature particle size stability has been met.
Authors:
M Postel; J G Riess; J G Weers
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Artificial cells, blood substitutes, and immobilization biotechnology     Volume:  22     ISSN:  1073-1199     ISO Abbreviation:  Artif Cells Blood Substit Immobil Biotechnol     Publication Date:  1994  
Date Detail:
Created Date:  1995-03-16     Completed Date:  1995-03-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9431307     Medline TA:  Artif Cells Blood Substit Immobil Biotechnol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  991-1005     Citation Subset:  IM    
Affiliation:
Unité de Chimie Moléculaire, Associée au C.N.R.S., Université de Nice-Sophia Antipolis, Parc Valrose, France.
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MeSH Terms
Descriptor/Qualifier:
Blood Substitutes / chemistry*
Cryopreservation
Drug Stability
Emulsions
Fluorocarbons / chemistry*
Temperature
Thermodynamics*
Chemical
Reg. No./Substance:
0/Blood Substitutes; 0/Emulsions; 0/Fluorocarbons

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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