Abstract
Conclusion
Supersonic radiation appears to be the most suitable method yet studied for preparing fat emulsions, suitable for intravenous use in man.
An emulsion of fat that could safely be given in quantity by vein was first developed by Yamakawa and his collaborators 1 in Japan. Recent observations in Latin America and in this country 2 have confirmed and extended their work and have furnished very suggestive clinical and experimental evidence of the value of such preparations. The technique used by Japanese and American workers is essentially similar: the fat or oil is mixed with purified egg lecithin (Merck's or Kahlbaum's) and water and passed through a 2-stage dairy homogenizer operating at 3000 to 4000 lb. pressure, after which the product is sterilized by heat in sealed containers. When suitable quantities are used, it is possible to obtain an emulsion in which practically all the lecithin-coated fat globules are less than 2μ in diameter with only an occasional one as large as 3 or 3.5μ. Such an emulsion passes through the lung capillaries with ease, 3 avoiding the danger of fat embolism, which may occur when the particles exceed 4μ in diameter. 4
A difficulty that has been experienced—both with Japanese and American preparations—is the limited time during which these emulsions are stable. In the course of a few weeks, more or less, the larger fat particles which are in less active Brownian movement tend to rise to the surface, forming a visible cream layer. Although the formation of the cream does not necessarily indicate an increased particle size, nevertheless the large fat particles are in close apposition, and there is danger of their coalescing to form larger aggregates.
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