In vitro dynamic solubility test: influence of various parameters

Area of Science:

• Materials Science
• Biocompatibility
• Environmental Health

Background:

• Mineral fibers are used in various applications, necessitating an understanding of their behavior in biological environments.
• Assessing the dissolution of mineral fibers in simulated physiological fluids (SPF) is crucial for evaluating potential health and environmental impacts.

Purpose of the Study:

• To investigate the dissolution of mineral fibers in simulated physiological fluids (SPF).
• To identify key parameters affecting solubility measurements in a dynamic test (Scholze and Conradt test).

Main Methods:

• Mineral fibers of varying compositions were exposed to simulated extracellular (pH 7.6) and intracellular (pH 4.5) fluids.
• Fiber solubility was determined by measuring released SiO2 and other ions.
• The Scholze and Conradt dynamic test was employed, analyzing parameters like SPF, test duration, and surface area/volume (SA/V) ratio.

Main Results:

• Solubility is highly dependent on pH; glasswool dissolves at pH 7.6 but not 4.5, while rockwool shows the opposite trend.
• Dissolution rate (v) is constant over time for slightly soluble fibers but decreases for highly soluble fibers.
• Increased SA/V ratio leads to a reduced dissolution rate.

Conclusions:

• The pH of simulated physiological fluids significantly impacts mineral fiber dissolution.
• Test parameters, particularly SA/V ratio and buffer composition, must be carefully controlled for accurate solubility measurements.
• Understanding fiber dissolution is essential for risk assessment and material design.