Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Atmospheric Chemistry Program Seminar

Inhalation and Sublingual Delivery of Medical Cannabinoids and Vaccines
by Robert Sievers,
University of Colorado, Environmental Program
"The development of cannabis products that conform to pharmaceutical level quality standards would be of great benefit to those attempting to use cannabis for medicinal purposes. Currently, the cannabis industry generates products that vary substantially in consistency of dosing, time of onset, and safety of administration route. The bioavailability of these products is not optimal due to a combination of inefficient absorption, first pass metabolism effects, and cannabinoid degradation. To combat these issues, we have developed a cannabinoid-containing dry powder that utilizes isolated, highly purified cannabinoids and excipients that are generally regarded as safe (GRAS) or have recently been determined in clinical trials of formulations to be safe for inhalation. The powder is suitable for respiratory delivery from a simple dry powder inhaler (DPI). Delivery to the lungs in this manner provides a consistent dose with a rapid onset of effects and avoids the bioavailability issues and first-pass metabolism encountered with other methods of administration. Various cannabinoids can also be combined in customized ratios targeted for the treatment of specific pathologies. A new US Patent #9,895,321 to the five authors (Sievers; Robert E., Cape; Stephen P., McAdams; David, Manion; J'aime, Pathak; Pankaj) was issued on February 20, 2018. Authors: Robert Sievers, Lia Rebits, Xuno Gildelamadrid"
Observations of particle organic nitrates from airborne/ground platforms: Insights into method improvement, vertical/geographical distribution, gas/particle partitioning, losses, and contribution to total particle nitrate
by Doug Day,
University of Colorado, ANYL ResSci, Jimenez group
"Organic nitrate formation in the atmosphere represents a sink of NOx and termination of the HOx /NOx ozone formation cycles, can act as a NOx reservoir transporting reactive nitrogen, and contributes to secondary organic aerosol formation. However, particle-phase organic nitrates (pRONO2) are rarely measured and thus poorly understood. Due to the increasing prevalence of aerosol mass spectrometer (AMS) field measurements and promise of its use in determining quantitative bulk organic nitrate functional group contribution to aerosols, a detailed evaluation of quantification methods is timely. A simple method that relies on the relative intensities of NO + and NO2 + intensities in the AMS spectrum, calibrated NOx + ratio for NH4NO3 , and inferred ratio for pRONO2 has been previously proposed as a way to apportion the total nitrate signal to NH4NO3 and pRONO2, and been used by several groups using a variety of different methods and assumptions. An extensive survey of NOx + ratios measured for various pRONO2 compounds and mixtures from multiple instruments, groups, and laboratory and field measurements shows that, in the absence of a pRONO2 standard, the pRONO2 NOx + ratio can be estimated using a ratio referenced to the calibrated NH4NO3 ratio, a so-called Ratio-of- Ratios (RoR). We systematically explore the viability, accuracy, and errors associated with quantifying pRONO2 with the AMS RoR NOx + ratio method using ground and aircraft field measurements conducted over a large range of conditions. Positive Matrix Factorization (PMF) of thermal denuder measurements was conducted to further explore the efficacy of the RoR NOx + ratio method and to construct volatility basis sets (VBS) of pRONO2 for several campaigns. A broad survey of ground and aircraft AMS measurements, applying the RoR NOx + ratio method, shows a pervasive trend of higher contribution of pRONO2 to total nitrate with lower total nitrate concentrations.
Simultaneous measurements of pRONO2 (applying the AMS RoR NOx ratio method) and of total (gas+particle) organic nitrate (totRONO2), organic aerosols (OA), and ammonium nitrate from aircraft and several ground campaigns were used to investigate vertical/geographical distributions, gas/particle partitioning, losses, and contributions to total particle nitrate (pTotNO3) over North America. pRONO2 and totRONO2 concentrations show strong vertical gradients, with a steep decrease from the top of the boundary layer (BL) up through the residual layer. However, pRONO2 was 10-30% of totRONO2 with little vertical gradient in gas/particle partitioning from the BL to upper troposphere (UT). pRONO2 contribution to OA shows a moderate increase with decreasing OA in the BL and free troposphere (~2-3% by mass of nitrate group) with higher contributions at the lowest OA (5-8%), mostly observed in the UT. In the BL, RONO2 gas/particle partitioning shows a trend with temperature, with higher particle-phase fraction at lower temperatures, as expected from partitioning theory. However, the temperature trend is much weaker than for single compound partitioning, which may be due to a broad mixture of species. Little to no dependence of pRONO2 /OA on RH or estimated particle water was observed in the BL, suggesting that losses of pRONO2 due to hydrolysis are too rapid to observe in this dataset and there may be a substantial fraction of pRONO2 species that are not prone to rapid hydrolysis."


Monday, April 30, 2018
12:00pm to 1:00pm


Ekeley S274