The RIFM approach to evaluating Natural Complex Substances (NCS)

The Research Institute for Fragrance Materials, Inc. (RIFM) has evaluated safety data for fragrance materials for 55 years. The safety assessment of Natural Complex Substances (NCS) is similar to that of discrete fragrance materials; all of the same endpoints are evaluated. A series of decision trees, reflecting advances in risk assessment approaches of mixtures and toxicological methodologies, follows a tiered approach for each endpoint using a 4-step process with testing only as a last resort: 1) evaluate available data on NCS; 2) verify whether the Threshold of Toxicological Concern (TTC) can be applied; 3) verify whether the NCS risk assessment can be achieved on a component basis; and 4) determine whether data must be generated. Using in silico tools, RIFM examined NCS similarities based on the plant part, processing, and composition of materials across 81 plant families to address data gaps. Data generated from the Creme RIFM Aggregate Exposure Model for over 900 fragrance NCS demonstrate that dermal exposure is the primary route of human exposure for NCS fragrance uses. Over a third of materials are below the most conservative TTC limits. This process aims to provide a comprehensive Safety Assessment of NCS used as a fragrance ingredient.

RIFM fragrance ingredient safety assessment, (2-endo,3-exo)-ethyl 3-(1-methylethyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate, CAS registry number 116044-44-1

In addition, the total systemic exposure to (2-endo,3-exo)-ethyl 3-(1-methylethyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate (3.3 μg/kg/day) is below the TTC (9 μg/kg/day; Kroes, 2007) for the repeated dose toxicity endpoint of a Cramer Class II material at the current level of use.

RIFM fragrance ingredient safety assessment, 6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde, CAS Registry Number 33885-51-7

No treatment-related effects at the low and mid doses were observed in gestation, viability and lactation indices, duration of gestation, parturition, sex ratio, maternal care, litter size, and early postnatal pup development consisting of mortality, clinical signs, anogenital distance, areola/nipple retention, T4 thyroid hormone levels, or macroscopic examination. However, the number of litters (N = 5) at the high dose was considered too low for toxicological evaluation. Thus, based on insufficient data at 120 mg/kg/day, the NOAEL for this study was considered to be 60 mg/kg/day (RIFM, 2020d).

RIFM fragrance ingredient safety assessment, cis-3-hexenyl methyl carbonate, CAS Registry Number 67633-96-9

The following paper presents the method of determination of the percolation threshold in cement composites with expanded graphite by impedance spectroscopy. Most of the applications of cement composites with conductive additives require exceeding the percolation threshold. The ionic conductivity of cement matrix below the percolation threshold has a major impact on the conductivity of the composite, as a result, it significantly hinders the exploitation of these composites. The electric properties of cement composites with expanded graphite were evaluated by DC measurements and impedance spectroscopy (IS). Based on Nyquist plots, two equivalent circuits were adopted for the composites. Next, the values of capacitance and inductance of cement composites with expanded graphite were calculated from the fitted equivalent circuits. The analysis of the results shows that the percolation threshold occurs when the reactance of the composite changes from captative to inductive. Comparison between the values of percolation threshold obtained from DC measurements and IS shows that the method is effective for cement composites with conductive additives.