The role of lecithin degradation on the pH dependent stability of halofantrine encapsulated fat nano-emulsions

Iman Haidar, Ian H Harding, Ian C Bowater, Daniel S Eldridge, William N Charman

Research output: Contribution to journalArticleResearchpeer-review

Abstract

We report on the successful incorporation of the antimalarial drug, halofantrine, into laboratory based soybean oil emulsions which were designed to mimic the commercially available parenteral fat emulsion, Intralipid®. A high pH (minimum of pH 9, preferable pH of 11) was required for the drug laden emulsion to remain stable on storage and also to resist breaking under various stresses. Ageing of lecithin samples on storage was noted to result indegradation and a decrease in pH. We argue that this is the main reason for a similar decrease in pH for lecithin based emulsions and subsequent instability in drug laden emulsions. As expected, incorporation of the drug (halofantrine) resulted in lower stability. The (intensity weighted) particle size increased from 281 nm for the drug free emulsion to 550 nm following a loading of 1 g L-1 of halofantrine, indicative of a lowering in stability and this was reflected in a shorter shelf life. Interestingly, incorporation of even higher concentrations of drug then resulted in better stability albeit never as stable as the drug free emulsion. We also report on unusual and complex surface tension behaviour for fresh lecithin where multiple critical concentrations points were observed.
Original languageEnglish
Pages (from-to)524-535
Number of pages12
JournalInternational Journal of Pharmaceutics
Volume528
Issue number1-2
DOIs
Publication statusPublished - 7 Aug 2017

Keywords

  • Intralipid
  • soybean emulsion
  • contact angle
  • surface tension
  • lecithin
  • halofantrine

Cite this

Haidar, Iman ; Harding, Ian H ; Bowater, Ian C ; Eldridge, Daniel S ; Charman, William N. / The role of lecithin degradation on the pH dependent stability of halofantrine encapsulated fat nano-emulsions. In: International Journal of Pharmaceutics. 2017 ; Vol. 528, No. 1-2. pp. 524-535.
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abstract = "We report on the successful incorporation of the antimalarial drug, halofantrine, into laboratory based soybean oil emulsions which were designed to mimic the commercially available parenteral fat emulsion, Intralipid{\circledR}. A high pH (minimum of pH 9, preferable pH of 11) was required for the drug laden emulsion to remain stable on storage and also to resist breaking under various stresses. Ageing of lecithin samples on storage was noted to result indegradation and a decrease in pH. We argue that this is the main reason for a similar decrease in pH for lecithin based emulsions and subsequent instability in drug laden emulsions. As expected, incorporation of the drug (halofantrine) resulted in lower stability. The (intensity weighted) particle size increased from 281 nm for the drug free emulsion to 550 nm following a loading of 1 g L-1 of halofantrine, indicative of a lowering in stability and this was reflected in a shorter shelf life. Interestingly, incorporation of even higher concentrations of drug then resulted in better stability albeit never as stable as the drug free emulsion. We also report on unusual and complex surface tension behaviour for fresh lecithin where multiple critical concentrations points were observed.",
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The role of lecithin degradation on the pH dependent stability of halofantrine encapsulated fat nano-emulsions. / Haidar, Iman ; Harding, Ian H ; Bowater, Ian C; Eldridge, Daniel S; Charman, William N.

In: International Journal of Pharmaceutics, Vol. 528, No. 1-2, 07.08.2017, p. 524-535.

Research output: Contribution to journalArticleResearchpeer-review

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