Oral Toxicokinetics, Tissue Distribution, and 28-Day Oral Toxicity of Two Differently Manufactured Food Additive Silicon Dioxides

Abstract

(1) Background: Synthetic amorphous silica (SAS) is widely used as a food additive and contains nano-sized particles. SAS can be produced by fumed and precipitated methods, which may possess different physiochemical properties, toxicokinetics, and oral toxicity. (2) Methods: The toxicokinetics of fumed SAS and precipitated SAS were evaluated following a single-dose oral administration in rats. The tissue distribution and fate of both SAS particles were assessed after repeated oral administration in rats for 28 d, followed by recovery period for 90 d. Their 28-d repeated oral toxicity was also evaluated. (3) Results: Precipitated SAS showed higher oral absorption than fumed SAS, but the oral absorption of both SAS particles was low (<4%), even at 2000 mg/kg. Our tissue-distribution study revealed that both SAS particles, at a high dose (2000 mg/kg), were accumulated in the liver after repeated administration for 28 d, but the increased concentrations returned to normal levels at 29 d, the first day of the recovery period. A higher distribution level of precipitated SAS than fumed SAS and decomposed particle fates of both SAS particles were found in the liver at 28 d. No significant toxicological findings were observed after 28-d oral administration, suggesting their low oral toxicity. (4) Conclusions: Different manufacturing methods of SAS can, therefore, affect its oral toxicokinetics and tissue distribution, but not oral toxicity.

Management of the poultry red mite Dermanyssus gallinae with physical control methods by inorganic material and future perspectives

“…Silicon dioxide has water/oil adsorption properties, which cause dehydration of the cell membrane of PRM after absorbing lipids from their cuticle ( Schulz et al, 2014 ). One of the advantages of silica products is their low oral toxicity ( Yoo et al, 2022 ).…”

Oral Excretion Kinetics of Food-Additive Silicon Dioxides and Their Effect on In Vivo Macrophage Activation

“…Our previous research reported the oral toxicokinetics of fumed and precipitated SiO 2 particles after a single-dose administration to rats, showing ~3.1% and ~3.9% absorption for the former and the latter, respectively [13]. Tissue distribution patterns demonstrated that both SiO 2 particles accumulated in only the liver at 28 d following repeated oral administration of 2000 mg/kg to rats for 28 d [13].…”

“…Our previous research reported the oral toxicokinetics of fumed and precipitated SiO 2 particles after a single-dose administration to rats, showing ~3.1% and ~3.9% absorption for the former and the latter, respectively [13]. Tissue distribution patterns demonstrated that both SiO 2 particles accumulated in only the liver at 28 d following repeated oral administration of 2000 mg/kg to rats for 28 d [13]. Notably, a significantly higher accumulation of precipitated SiO 2 than fumed SiO 2 was found in the liver, but the elevated levels returned to normal basal levels at 1 d of the recovery period [13].…”

Fate Determination and Characterization of Food Additive Silicon Dioxide and Titanium Dioxide in Commercial Foods

“…Determining whether SiO 2 and TiO 2 are present as intact particles, aggregates, or dissolved forms is important to understand and predict their potential toxicity. Orally taken SiO 2 is generally considered to be not toxic at actual usage levels [17][18][19]. However, some contradictory results were also reported, showing its potential toxicity in terms of oxidative stress, inflammation response, and intestinal barrier dysfunction, although most studies were performed using in vitro systems [20][21][22].…”

“…In the previous study, we developed a Triton X-114 (TX-114)-based CPE method to separate zinc oxide (ZnO) particles as intact forms from com-mercial foods and biomatrices without pre-treatments [14]. The CPE approach was also developed for SiO 2 in biomatrices and its fates were determined in cell lines and tissues [17]. In this study, the CPE method was further optimized for the most widely applied food additive particles, SiO 2 and TiO 2 , in food matrices to determine their dissolved, aggregated, or particle fates in commercial food products.…”