222 research outputs found

    BUDESONIDE COMPATIBILITY STUDY WITH EXCIPIENTS FOR PREPARATION OF NANOPARTICLE

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    Objective: As a condition of acceptance and approval of any pharmaceutical product, stability studies ensuring the durability of the consistency, stability and efficacy of the product during the shelf life are taken into consideration. These studies should be conducted according to the guidelines provided by ICH, WHO and other agencies as intended. Methods: The aim of this research was to evaluate the stability of the budesonide solution in some solutions and excipients and to further study the production of budesonide nanoparticles. In order to study the Budesonide stability mixture of solvent and polymers were used. To study the effect of temperature and relative humidity on the stability of budesonide preparations, prepared mixtures were stored under Accelerated (40 °C±2 °C/75 percent RH±5 percent RH), Intermediate (30 °C±2 °C/65 percent RH±5 percent RH), Long-term (25 °C±2 °C/60 percent RH±5 percent RH) and at 2-8 °C. Results: Budesonide showed good compatibility at defined stability conditions in one month. Such type of preformulation compatibility study is necessary in preparation of nanoparticles. Conclusion: It would be helpful in screening and identifying a suitable solvent, polymer and mixture at a desired concentration

    Simulating secondary organic aerosol in a regional air quality model using the statistical oxidation model – Part 1: Assessing the influence of constrained multi-generational ageing

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    Multi-generational oxidation of volatile organic compound (VOC) oxidation products can significantly alter the mass, chemical composition and properties of secondary organic aerosol (SOA) compared to calculations that consider only the first few generations of oxidation reactions. However, the most commonly used state-of-the-science schemes in 3-D regional or global models that account for multi-generational oxidation (1) consider only functionalization reactions but do not consider fragmentation reactions, (2) have not been constrained to experimental data and (3) are added on top of existing parameterizations. The incomplete description of multi-generational oxidation in these models has the potential to bias source apportionment and control calculations for SOA. In this work, we used the statistical oxidation model (SOM) of Cappa and Wilson (2012), constrained by experimental laboratory chamber data, to evaluate the regional implications of multi-generational oxidation considering both functionalization and fragmentation reactions. SOM was implemented into the regional University of California at Davis / California Institute of Technology (UCD/CIT) air quality model and applied to air quality episodes in California and the eastern USA. The mass, composition and properties of SOA predicted using SOM were compared to SOA predictions generated by a traditional two-product model to fully investigate the impact of explicit and self-consistent accounting of multi-generational oxidation. Results show that SOA mass concentrations predicted by the UCD/CIT-SOM model are very similar to those predicted by a two-product model when both models use parameters that are derived from the same chamber data. Since the two-product model does not explicitly resolve multi-generational oxidation reactions, this finding suggests that the chamber data used to parameterize the models captures the majority of the SOA mass formation from multi-generational oxidation under the conditions tested. Consequently, the use of low and high NOx yields perturbs SOA concentrations by a factor of two and are probably a much stronger determinant in 3-D models than multi-generational oxidation. While total predicted SOA mass is similar for the SOM and two-product models, the SOM model predicts increased SOA contributions from anthropogenic (alkane, aromatic) and sesquiterpenes and decreased SOA contributions from isoprene and monoterpene relative to the two-product model calculations. The SOA predicted by SOM has a much lower volatility than that predicted by the traditional model, resulting in better qualitative agreement with volatility measurements of ambient OA. On account of its lower-volatility, the SOA mass produced by SOM does not appear to be as strongly influenced by the inclusion of oligomerization reactions, whereas the two-product model relies heavily on oligomerization to form low-volatility SOA products. Finally, an unconstrained contemporary hybrid scheme to model multi-generational oxidation within the framework of a two-product model in which ageing reactions are added on top of the existing two-product parameterization is considered. This hybrid scheme formed at least 3 times more SOA than the SOM during regional simulations as a result of excessive transformation of semi-volatile vapors into lower volatility material that strongly partitions to the particle phase. This finding suggests that these hybrid multi-generational schemes should be used with great caution in regional models

    Health impact assessment of coal-fired boiler retirement at the Martin Drake and Comanche power plants

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    Includes bibliographical references.Health impact assessment (HIA) is a suite of tools used to characterize potential health effects of policies, projects, or regulations. The objective of this HIA was to understand the impact of decommissioning units at two large coal-fired power plants on mortality and morbidity in the Southern Front Range region of Colorado. Based on Community Multiscale Air Quality (CMAQ) chemical transport models of fine particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) and ozone (O3), we modeled five potential emissions reductions scenarios and estimated the potential health benefits of reduced exposures to PM2.5 and ozone for premature deaths, cardiovascular and respiratory hospitalizations, and other health outcomes for ZIP codes in the Southern Front Range region, including the cities of Denver, Colorado Springs, and Pueblo. Health Benefits Scenarios 1 and 2 estimated the health benefits of shutting down most units at the Comanche plant in Pueblo, CO (one newer unit remained operational) relative to a baseline scenario using emissions from 2011 (Scenario 1) or a counterfactual baseline scenario that accounted for sulfur dioxide emissions controls (scrubbers) installed at the Martin Drake plant in Colorado Springs in 2016 (Scenario 2). Health Benefits Scenario 3 estimated the benefits of shutting down the Martin Drake plant relative to the 2011 baseline. Health Benefits Scenario 4 estimated the health benefits of shutting down the Martin Drake power plant and shutting down all but one boiler at the Comanche power plant relative to a 2011 emissions baseline. Health Benefits Scenario 5 estimated the marginal health benefits of decommissioning these plants (with one remaining coal-fired boiler at Comanche) relative to a counterfactual baseline year that considered emissions controls installed at the Martin Drake facility in 2016. In addition to estimating the number of deaths, hospitalizations, and other health outcomes that would potentially be avoided by reducing emissions at these facilities, we also estimated the monetary impact using outcome valuations typically used in US EPA health benefits analyses and examined the environmental justice implications of reduced emissions and exposures across the Southern Front Range. • For Health Benefits Scenario 1 (Comanche Units 3 and 4 were “zeroed out” and compared to a baseline where all other emissions were at 2011 levels), we estimated that reducing population exposures to PM2.5 would result in 1 (95% CI: 0 - 1) fewer premature death each year. Reductions in PM2.5 and O3 exposures would also result in fewer restricted activity days among adults [5 (95% CI: -3 – 95)] and fewer missed school days for children [27 (95% CI: -19- 582)]. Benefits of retiring the Comanche units were similar when emissions controls at Martin Drake are taken into account (Health Benefits Scenario 2). • For Health Benefits Scenario 3 (emissions at Martin Drake were “zeroed out”), we estimated that reducing population exposures to PM2.5 and O3 would result in 4 (95% CI: 2 - 5) and < 1 (95% CI: 0 - 1) fewer premature deaths each year, respectively. Reductions in PM2.5 and O3 exposures would also result in fewer restricted activity days among adults [10 (95% CI: 0 – 74)] and fewer missed school days for children [4 (95% CI: 2- 5)]. • For Health Benefits Scenario 4, we estimated that reducing population exposures to PM2.5 and O3 would result in 4 (95% CI: 2 - 6) and < 1 (95% CI: 0 - 1) fewer premature deaths each year, respectively. Among the largest annual health benefits are avoided asthma symptom days among children [16 (95% CI: -1 – 141) due to PM2.5 and 13 (95% CI: -348 - 972) due to O3] and minor restricted activity days among adults [69 (95% CI: 0 - 488) due to PM2.5 and 71 (95% CI: -31 - 750) due to O3]. We also estimated that, for Health Benefits Scenario 1, children in the study area would miss 77 (95% CI: -77 - 1180) fewer days of school each year due to lower O3 exposures. • Annual health benefits were lower for Health Benefits Scenario 5 compared to Scenario 4 due to the smaller change in exposure concentration after accounting for the control technologies installed at Martin Drake in 2016. For Health Benefits Scenario 5, we estimated that reducing population exposures to PM2.5 and O3 would result in 2 (95% CI: 1 - 3) and < 1 (95% CI: 0 - 1) fewer premature deaths each year, respectively. Other annual benefits under Health Benefits Scenario 2 included 2 (95% CI: -17 – 44) and 9 (-242 – 678) avoided asthma symptom days due to PM2.5 and O3 exposures, respectively; 28 (95%CI: -2 – 188) and 48 (95%CI: -16 – 513) minor restricted activity days due to PM2.5 and O3 exposures; and 53 (95% CI: -48 – 833) avoided school absences among children due to O3 exposures. • Monetized health benefits when both plants were “zeroed out” ranged from 4.2million(954.2 million (95% CI: 2.1 million - 7.2million)forHealthBenefitsScenario4to7.2 million) for Health Benefits Scenario 4 to 1.7 million (95% CI: $0.8 million – 3.2 million) for Health Benefits Scenario 5. Benefits tended to be smaller when only one plant was considered. In all of the analyses, the monetized impacts were driven by the value of avoided premature mortality. In addition, we found that ZIP codes with lower median incomes tended to receive a greater share of the health benefits of decreasing exposures to PM2.5 and O3 resulting from power plant shutdowns. This finding suggests that reducing emissions at the power plants could potentially alleviate some environmental justice concerns in the area

    Multi-generational oxidation model to simulate secondary organic aerosol in a 3-D air quality model

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    Multi-generational gas-phase oxidation of organic vapors can influence the abundance, composition and properties of secondary organic aerosol (SOA). Only recently have SOA models been developed that explicitly represent multi-generational SOA formation. In this work, we integrated the statistical oxidation model (SOM) into SAPRC-11 to simulate the multi-generational oxidation and gas/particle partitioning of SOA in the regional UCD/CIT (University of California, Davis/California Institute of Technology) air quality model. In the SOM, evolution of organic vapors by reaction with the hydroxyl radical is defined by (1) the number of oxygen atoms added per reaction, (2) the decrease in volatility upon addition of an oxygen atom and (3) the probability that a given reaction leads to fragmentation of the organic molecule. These SOM parameter values were fit to laboratory smog chamber data for each precursor/compound class. SOM was installed in the UCD/CIT model, which simulated air quality over 2-week periods in the South Coast Air Basin of California and the eastern United States. For the regions and episodes tested, the two-product SOA model and SOM produce similar SOA concentrations but a modestly different SOA chemical composition. Predictions of the oxygen-to-carbon ratio qualitatively agree with those measured globally using aerosol mass spectrometers. Overall, the implementation of the SOM in a 3-D model provides a comprehensive framework to simulate the atmospheric evolution of organic aerosol

    Estimates of non-traditional secondary organic aerosols from aircraft SVOC and IVOC emissions using CMAQ

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    Utilizing an aircraft-specific parameterization based on smog chamber data in the Community Multiscale Air Quality (CMAQ) model with the volatility basis set (VBS), we estimated contributions of non-traditional secondary organic aerosols (NTSOA) for aircraft emissions during landing and takeoff (LTO) activities at the Hartsfield–Jackson Atlanta International Airport. NTSOA, formed from the oxidation of semi-volatile and intermediate volatility organic compounds (S/IVOCs), is a heretofore unaccounted component of fine particulate matter (PM2.5) in most air quality models. We expanded a prerelease version of CMAQ with VBS implemented for the Carbon Bond 2005 (CB05) chemical mechanism to use the Statewide Air Pollution Research Center 2007 (SAPRC-07) chemical mechanism and added species representing aircraft S/IVOCs and corresponding NTSOA oxidation products. Results indicated that the maximum monthly average NTSOA contributions occurred at the airport and ranged from 2.4 ng m−3 (34 % from idle and 66 % from non-idle aircraft activities) in January to 9.1 ng m−3 (33 and 67 %) in July. This represents 1.7 % (of 140 ng m−3) in January and 7.4 % in July (of 122 ng m−3) of aircraft-attributable PM2.5 compared to 41.0–42.0 % from elemental carbon and 42.8–58.0 % from inorganic aerosols. As a percentage of PM2.5, impacts were higher downwind of the airport, where NTSOA averaged 4.6–17.9 % of aircraft-attributable PM2.5 and, considering alternative aging schemes, was as high as 24.0 % – thus indicating the increased contribution of aircraft-attributable SOA as a component of PM2.5. However, NTSOA contributions were generally low compared to smog chamber results, particularly at idle, due to the considerably lower ambient organic aerosol concentrations in CMAQ compared to those in the smog chamber experiments
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