Table 4. Biodissolution Studies Assessing Fibers or Nanomaterials in pH 4.5 Extraction Fluids.

study	pH 4.5 extraction fluid	test materials	comparison of abiotic dissolution rate to in vitro cellular and/or in vivo effects
Guldberg et al.17	Five different fluids (Table 2)	MMVF21, MMVF22, and MMVF34	apart from the fluid containing citric acid, accurate prediction of in vivo pathogenicity and lung clearance rates as reported in IARC89 (Table 65)
Stefaniak et al.22	PSF	beryllium oxide	accurate prediction of in vitro dissolution in mouse J774A.1 cells and in vivo dissolution in dogs (acute inhalation exposure)
Koltermann-Jülly et al.57 with addendum (2019)		different (nano-)forms of BaSO4, CeO2, Cu-phthalocyanine/CuO, Fe2O3, SiO2, SrCO3, TiO2, and ZnO	good correlation with in vitro dissolution in cultured rat NR8383 AMs and with pulmonary clearance in rat STISs
Keller et al.58		nano- and nonnano forms of BaSO4, TiO2, kaolin, and bentonite and nanoforms of ZnO w/ and w/o coating	also method parameters such as flow rate are critical: with PSF, all benchmark materials were correctly predicted in a specific valid range of SA/V
Keller et al.59		BaSO4	good correlation with in vivo pulmonary clearance in rats and with in vivo transformation (Ostwald ripening) in rats
Jeong et al.84	as published by Stopford et al.43	CuO NPs and indium oxide NPs	consistent with pulmonary effects observed in rats upon oral pharyngeal aspiration
Adamcakova-Dodd et al.85		ZnO NPs	good correlation with dissolution in 2- and 13-week mouse inhalation toxicity studies
Latvala et al.86	as published by Midander et al.21	Nanosized and micron-sized Ni-containing particles	insufficient correlation—dissolution in the cell culture was slower than in the abiotic system
Shinohara et al.42	as published by Shinohara et al.42	nano- and micron-sized NiO	Good correlation with pulmonary clearance in the rat intratracheal instillation studies