Meaning
Simulating chemical release into physiological fluids identifies the fraction of a substance capable of entering an organism through digestive or dermal exposure. In material evaluation, a bioaccessibility bioassay measures the quantity of additives, residual monomers or degraded fragments that dissolve into synthetic gastrointestinal juices. The test exposes a crushed or intact polymer sample to agitated synthetic enzymes at controlled temperature and acidity levels.
Mass spectrometry quantifies the extracted chemical fraction after filtration.
Extraction Mechanism
Fluid composition and agitation dynamics dictate the dissolution kinetics of lipophilic compounds during physiological testing. During a bioaccessibility bioassay, synthetic digestive fluids digest matrix surface layers to mobilize target compounds. Temperature stability at body conditions remains necessary throughout the extraction phase.
Higher surface area in ground regrind particles accelerates the release rate compared to intact moulded parts.
Polymer Migration
Additive formulation choices dictate how plasticizers and antioxidants leach from a solid polymer matrix into contact media. In recycled packaging resins, a bioaccessibility bioassay detects non-intentionally added substances that migrate under digestive conditions. Plasticizer concentration gradients drive molecular diffusion toward the specimen boundary.
High migration rates increase raw material costs by requiring higher antioxidant loading to maintain thermal stability.
Testing Boundary
In vitro extraction values represent maximum potential exposure rather than systemic biological uptake. A bioaccessibility bioassay does not account for intestinal epithelial wall transport or liver metabolism. The test applies exclusively to chemical release potential under standardized laboratory fluid exposure.
