Investigation of the Particle Size Distribution of a Model Intravenous Emulsion

Westesen, Kirsten; Wehler, Thomas

doi:10.1002/jps.2600821211

Cited by 22 publications

(11 citation statements)

References 18 publications

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“…This fraction, thought to be indicative of phospholipid vesicles eluting at or near the void peak, is reminiscent of several recent studies which have demonstrated the presence of small (<100 nm) unilamellar vesicles in Intralipid which appear in the infranatant after ultracentrifugation but are also detected in TEM micrographs, though not by PCS measurements of the native emulsions. [6][7][8] Westesen and Wehler estimated that approximately 0.34 wt % of the phospholipids in an emulsion which contained a total of 1.8% phospho-…”

Section: Resultsmentioning

confidence: 99%

“…Recent studies suggest, however, that the classical viewpoint of oil-inwater emulsions as dispersions of oil droplets in an aqueous continuous phase, with the interface stabilized by a monolayer of surfactant, may be an inadequate representation. [4][5][6][7][8][9] In Intralipid emulsions, the amount of phospholipid (12 g/L) is the same in formulations containing 10%, 20%, and 30% soybean oil. Thus it is obvious that a pronounced excess of surfactant is present, at least in the 10% and 20% formulations.…”

Section: Introductionmentioning

confidence: 99%

“…9 Recent studies have also shown that some of the phospholipid in lipid emulsions is present in the form of small unilamellar vesicles or liposomes. [5][6][7][8] Li and Caldwell recently examined Intralipid and Liposyn using a combination of sedimentation fieldflow fractionation (sedFFF) and photon correlation spectroscopy (PCS) and proposed that the emulsion droplets may contain multiple surfactant layers and may also include entrapped aqueous volume within the droplet. 4 Rydhag and Wilton concluded that several layers of phospholipid are necessary to stabilize o/w emulsions.…”

Section: Introductionmentioning

confidence: 99%

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Compositional Heterogeneity in Parenteral Lipid Emulsions after Sedimentation Field Flow Fractionation

Venkatesh¹,

Li²,

Caldwell³

et al. 1998

Journal of Pharmaceutical Sciences

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This study examines the size and compositional heterogeneity of particles in a commercial lipid emulsion (Intralipid) before and after equilibration with penclomedine, a highly lipophilic cytotoxic agent. Emulsions were fractionated by sedimentation field-flow fractionation (sedFFF), and particle sizes of the monodisperse fractions were determined by photon correlation spectroscopy. The triglyceride (TG), phosphatidylcholine (PC), and penclomedine (in drug loaded emulsions) contents in each fraction were determined by HPLC. The aqueous-entrapped volume within Intralipid was determined to be approximately 10% by size-exclusion chromatography using [3H]mannitol. Thirteen sedFFF fractions collected from the drug free emulsions yielded particles ranging in size from 154 to 423 nm. Total channel recoveries were 89% and 95% for TG and PC, respectively. Apparent particle densities varied significantly with size, suggesting heterogeneity in composition as confirmed by PC/TG mass ratios which varied dramatically. Computer fits of the distribution profiles suggested populations of phospholipid vesicles and oil droplets containing excess phospholipid in addition to classical emulsion droplets. Drug loading induced a significant shift of the predominant triglyceride containing population to a larger particle size. The penclomedine distribution profile closely mimicked that of the TG rather than the PC fraction. These studies suggest the need to consider not only size distribution but also compositional distribution in characterizing parenteral emulsions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Compositional Heterogeneity in Parenteral Lipid Emulsions after Sedimentation Field Flow Fractionation

Venkatesh¹,

Li²,

Caldwell³

et al. 1998

Journal of Pharmaceutical Sciences

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“…This observation agrees with presence of a third emulsifier phase at the O/W interface suggested by Friberg et al ). Westesen showed the existence of triple layers in lecithin stabilized vegetable oil emulsions using synchrotron X-ray scattering (Westesen and Wehler, 1993), but for their system they found that not more than a monolayer is needed for stable emulsions. The addition of β-lactoglobulin has also little effect on the formation and the formed DOPC layer when the DOPC is dispersed in the oil phase.…”

Section: Liquid-liquid Interfaces (Emulsions and Vesicles)mentioning

confidence: 99%

Food Emulsifiers and Their Applications

2008

120

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“…Droplets in typical food and pharmaceutical emulsions can very well be much smaller than 1 µm in practice. Nanoemulsions are especially important for pharmaceutical applications, where sizes below 300-400 nm are mandatory 10 . The aim is therefore to provide a model for this important class of nanoemulsions to be analysed via NMR.…”

Section: Introductionmentioning

confidence: 99%

Interpretation of NMR diffusometry data regarding droplet size distributions in micro- and nanoemulsions

Sommerling

Simon

Haber

et al.

Proceedings of the XIII International Conference on the Applications of Magnetic Resonance in Food Science

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Nuclear magnetic resonance (NMR) diffusometry allows to measure droplet size distributions in emulsions. This non-invasive, nondestructive method has several advantages compared to common mainly optical methods for droplet sizing. NMR requires almost no sample preparation, unlike optical methods or cryoTEM, where samples need to be transparent and preparation or dilution is necessary. The established method, combining the concept of Murday and Cotts for diffusion in a limited spherical geometry with Packer and Rees, assuming a log-normal distribution for the droplet sizes, has limitations regarding the distribution and size range of droplets. There are approaches to overcome the limitations raised by the statistical log-normal distribution. A very successful approach is a numerical method, the regularisation, which does not assume any distribution form. In this work, we discuss the interpretation of NMR PFG-STE data leading to droplet size distributions in accordance to the established methods and the regularisation. We also address the problem of the lower size limitations and propose a way to use the Stokes-Einstein equation to gain droplet size distributions (DSD) for emulsions with droplets smaller than 1 µm of OW emulsions.

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Investigation of the Particle Size Distribution of a Model Intravenous Emulsion

Cited by 22 publications

References 18 publications

Compositional Heterogeneity in Parenteral Lipid Emulsions after Sedimentation Field Flow Fractionation

Compositional Heterogeneity in Parenteral Lipid Emulsions after Sedimentation Field Flow Fractionation

Food Emulsifiers and Their Applications

Interpretation of NMR diffusometry data regarding droplet size distributions in micro- and nanoemulsions

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