Paper
GUO Huiqing, GU Yanli, YANG Xiaoguang, BAI Huizhong, ZHU Aijun, Temuer, WANG Zhaoyang
In order to develop an oral negative computerized tomography(CT) contrast agent to improve the
detection rate of small gastrointestinal lesions and overcome the poor imaging performance of existing contrast agents,
an oral O/W nanoemulsion using white oil as the oil phase was prepared by high-pressure homogenization. Then, its
physicochemical properties, stability, and imaging effects were systematically evaluated. First, the emulsifier was screened
via pseudo-ternary phase diagrams, while formulation composition and preparation process were optimized by single-factor
experiments and central composite design-response surface methodology. Subsequently, the nanoemulsion prepared by
the optimized process was characterized for particle size, ζ potential, morphology, viscosity, and stability, and its in vitro
imaging capability was further evaluated via CT values and using an ex vivo porcine intestinal model. The results showed
that the nanoemulsion exhibited uniform particle size and good physical stability. It remained stable under acidic, alkaline,
high-temperature, and centrifugal conditions, but was susceptible to intense light and high humidity, thus requiring lightproof
and moisture-proof storage. The prepared white oil nanoemulsion achieved a CT value of ﹣ 91.1 HU. In the ex vivo
porcine intestinal model, the nanoemulsion yielded a markedly higher contrast-to-noise ratio than water, enabling clearer
visualization of the intestinal wall. As a novel oral negative CT contrast agent, this white oil nanoemulsion features a simple preparation process, stable properties under conventional conditions, and excellent in vitro imaging performance, providing
a promising alternative for CT diagnosis of small gastrointestinal lesions.
