An Analysis of Nasal Irritation Thresholds Using a New Solvation Equation

In the present paper we have developed a quantitative structure-activityrelationship (QSAR) equation for nasal pungency caused by nonreactivevolatile organic compounds (VOCs). Our QSAR was developed uponpreviously published nasal pungency thresholds in anosmics,i.e., patients lacking a sense of smell and thus respondingonly to sensory irritation evoked by trigeminal nerve stimulation.The reported solvation equation, which fits the data with considerableprecision, describes sensory potency in terms of interactionvia electron pairs, dipolarity/polarizability, hydrogen bondacidity and basicity, and hydrophobicity. It correspondinglysuggests relevant physicochemical properties of the biophasewhere the sensory response is brought about. The equation impliesthat in the range of molecular size where nonreactive VOCs canproduce any pungency, transport from the air to the biophasestrictly determines potency. In this respect, the potency ofnasal pungency shares characteristics with the ability of VOCsto cause narcosis and anesthesia.