Ultrasonic spectroscopy study of globule aggregation in parenteral fat emulsions containing calcium chloride

Ultrasonic attenuation spectroscopy has been used to study globule aggregat ion in parenteral fat emulsions. The ultrasonic attenuation spectrum (from 1 to 100 MHz) of a 12 vol % parenteral emulsion was measured at 25 degrees C. Globule aggregation was then induced in the emulsion by titrating with c alcium chloride (0-3.28 mM CaCl2). Dramatic changes in the attenuation spec trum of the emulsion were observed when the globules aggregated, which coul d be attributed to changes in either the spatial distribution (flocculation ) or the size distribution (coalescence) of the globules. The change in glo bule size during aggregation was calculated using ultrasonic scattering the ory assuming that the aggregates are spherical and have properties similar to those of the disperse phase. Ultrasonics has advantages over many other technologies because it can be used to analyze emulsions that are concentra ted and optically opaque in situ.