No abstract

There is increasing concern about the association of respiratory disease with indoor air quality and environmental atmospheric pollution. Associated with this is the fact that in many countries there has been a significant increase in the prevalence of asthma. Against this background there is a need to address the toxicological, occupational and public health problems associated with the ability of some chemicals to cause allergic sensitization of the respiratory tract and occupational asthma. By definition allergic sensitization of the respiratory tract to chemicals is dependent upon the stimulation of an adaptive immune response that leads to development of respiratory allergy and/or asthma. Although IgE antibody is associated typically with respiratory sensitization to protein allergens, there is less certainty about the role played by antibodies of this type in chemical respiratory allergy and occupational asthma. There are currently no validated or widely accepted methods/models for the identification and characterization of chemicals that have the potential to induce allergic sensitization of the respiratory tract. These and other areas of uncertainty were debated during the course of and following a two day Workshop. The primary purpose of the Workshop was to consider the important clinical and toxicological issues associated with chemical respiratory allergy, and to identify key questions that need to be answered if real progress is to be made.

This study measured postapplication exposure levels of fragrance materials in a surrogate air freshener formulation in an environmentally-controlled exposure room (ECER). A five-s spray was released to simulate normal consumer use conditions. Time-course airborne fragrance material levels were sampled with Tenax tubes, and aerosol size distributions were monitored with a TSI 3320 aerodynamic particle sizer. Triplicate experiments were performed for each of the control/test substances. The control substance (unfragranced formulation) experiments indicated that the airborne fragrance materials were not detected, suggesting that the base propellant formulation did not interfere with the sampling procedure or analytical results. The test substance experiments found that the higher the volatility of the fragrance material, the higherthe airborne fragrance concentration within the ECER. In the adult breathing zone height, the maximum concentrations of the nine fragrance materials ranged from 108 to 347 microg/m3 during the first minute postapplication. In the child breathing zone height, the maximum fragrance material concentrations ranged from 125 to 362 microg/m3 during 2-6 min postapplication. Particle size distributions indicated that approximately 60-70% of the generated aerosols were less than 1 microm aerodynamic diameter. Initial peak particle mass concentrations (<5 microm) were 800-1000 microg/m3 during the first minute postapplication. Following initial peak concentrations, there was approximately 10-15 min of fluctuation, and then particle levels decayed gradually and exponentiallyto near background levels. Exposure to the test formulation would originate from two components: particle-bound and vapor-phase fragrance materials. Particle-bound fragrance exposure accounted for approximately 47% and 72% of the total exposures during the first minute postapplication period in the adult and child breathing zone heights, respectively.

No abstract

The vehicle in which an allergen is presented to the skin has been recognized to have an effect on the skin-sensitizing potency of the allergen. Typical vehicles used to evaluate the skin sensitization potential of fragrance materials include ethanol, diethyl phthalate, or a combination of the two. The authors conducted a series of studies to evaluate each of these vehicles for their utility in the murine local lymph node assay and to investigate the potential differences in skin sensitization resulting from their use. Four fragrance materials were tested in four different vehicles. The test materials were p-t-butyl-alpha-methylhydrocinnamic aldehyde, geraniol, eugenol, and hydroxycitronellal. The vehicles were diethyl phthalate, 1:3 ethanol:diethyl phthalate, 3:1 ethanol:diethyl phthalate, and ethanol. Each of the fragrance materials was tested at five dose levels ranging from 0.3% to 50% w/v. In all four vehicles, each material tested elicited positive responses, exhibiting weak to moderate skin sensitization potential. Overall, p-t-butyl-alpha-methylhydrocinnamic aldehyde exhibited the most potency, followed by eugenol, geraniol, and hydroxycitronellal. The sensitization potential of both p-t-butyl-alpha-methylhydrocinnamic aldehyde and geraniol was greatest when the vehicle was ethanol. The sensitization potential of eugenol was greatest in 3:1 ethanol:diethyl phthalate, but the sensitization potential for hydroxycitronellal was greatest in 1:3 ethanol:diethyl phthalate. The strength of the sensitization response was observed to vary with the vehicle; however, the results did not show any clear pattern of one vehicle over another regarding skin sensitization.