Palatability and Stability Studies to Optimize a Carvedilol Oral Liquid Formulation for Pediatric Use

Carvedilol (CARV) is a blocker of α- and β- adrenergic receptors, used as an "off-label" treatment for cardiovascular diseases in pediatrics. Currently, there is no marketed pediatric-appropriate CARV liquid formulation, so its development is necessary. Palatability (appreciation of smell, taste, and aftertaste) is a key aspect to be considered during the development of pediatric formulations since only formulations with good palatability also have adequate acceptability in this population. Consequently, the aim of this research was to assess the palatability and acceptability of different CARV formulations using an in vivo taste assessment (ID Number PR103/22) in order to select the highest palatability-rated CARV formulation. The preparation of CARV formulations was based on a reference 1 mg/mL CARV solution, which contains malic acid as a solubilizing agent. Subsequently, sucralose and flavoring agents were added and mixed until complete dissolution to the corresponding formulations. Adult volunteers participated in this study and evaluated the taste and odor of various CARV formulations through a questionnaire and a sensory test. The mean palatability score, measured on a 10-point scale, increased from 1.60 for the unflavored control to 7.65 for the highest-rated flavored formulation. Moreover, the bitterness of the optimized CARV formulation was reduced from 66.67% to 17.86%, and the taste pleasantness was increased from 25/100 to 73/100. This optimized CARV formulation contains a sweetening agent, sucralose, in addition to two flavoring agents at appropriate concentrations for pediatrics. Furthermore, the physicochemical and microbiological stability of the optimized CARV formulation were evaluated for 6 months at 25, 30, and 40 °C, in addition to in-use stability for 15 days at 25 °C, whose results were confirmed. Thus, we successfully developed a palatable CARV liquid solution that contains excipients appropriate for pediatrics and is stable under the studied conditions.

Correlation between Lignin-Carbohydrate Complex Content in Grass Lignins and Phenolic Aldehyde Production by Rapid Spray Ozonolysis

We provide strong evidence that the amounts of phenolic aldehydes (vanillin and p-hydroxybenzaldehyde, pHB) selectively released during rapid ozonolysis of grass lignins are correlated with the unsubstituted aryl carbons of lignin-carbohydrate complexes present in these lignins. In the case of acetosolv lignin from corn stover, we observed a steady yield of vanillin and pHB (cumulatively ∼5 wt % of the initial lignin). We demonstrate the continuous ozonolysis of the lignin in a spray reactor at ambient temperature and pressure. In sharp contrast, similar ozonolysis of acetosolv lignin from corn cobs resulted in a twofold increase in the combined yield (∼10 wt %) of vanillin and pHB. Structural analysis with ¹H-¹³C heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance revealed that signals assigned to unsubstituted aryl carbons of lignin-carbohydrate complexes are quantitatively correlated to phenolic aldehyde production from spray ozonolysis. The ratios of the integrated peak volumes corresponding to coumarates and ferulates in the HSQC spectra of cob and corn stover lignins (SLs) are 2.4 and 2.0, respectively. These ratios are nearly identical to the observed 2.3-fold increase in pHB and 1.8-fold increase in vanillin production rates from corn cob lignin compared to corn SL. Considering that the annual U.S. lignin capacity from these grass lignin sources is ∼60 million MT, the value creation potential from these flavoring agents is conservatively ∼$50 million annually from just 10% of the lignin. These new insights into structure/product correlation and spray reactor characteristics provide rational guidance for developing viable technologies to valorize grass lignins.

Assessment of worker chemical exposures in California vape shops

E-cigarettes are battery-operated devices that heat a liquid mixture to make an aerosol that is inhaled, or vaped, by the user. Vape shops are retail environments designed to fulfill customer demand for diverse e-liquid flavors and hardware options, which create unique worker exposure concerns. To characterize exposures to vape shop workers, especially to flavoring chemicals associated with known respiratory toxicity, this study recruited vape shops from the San Francisco Bay Area. In six shops, we measured air concentrations for volatile organic compounds, formaldehyde, flavoring chemicals, and nicotine in personal and/or area samples; analyzed components of e-liquids vaped during field visits; and assessed metals on surface wipe samples. Interviews and observations were conducted over the course of a workday in the same six shops and interviews were performed in an additional six where sampling was not conducted. Detections of the alpha-diketone butter flavoring chemicals diacetyl and/or 2,3-pentanedione were common: in the headspace of purchased e-liquids (18 of 26 samples), in personal air samples (5 of 16), and in area air samples (2 of 6 shops). Two exceedances of recommended exposure limits for 2,3-pentanedione (a short-term exposure limit and an 8-hr time-weighted average) were measured in personal air samples. Other compounds detected in the area and personal air samples included substitutes for diacetyl and 2,3-pentanedione (acetoin and 2,3-hexanedione) and compounds that may be contaminants or impurities. Furthermore, a large variety (82) of other flavoring chemicals were detected in area air samples. None of the 12 shops interviewed had a health and safety program. Six shops reported no use of any personal protective equipment (PPE) (e.g., gloves, chemical resistant aprons, eye protection) and the others stated occasional use; however, no PPE use was observed during any field investigation day. Recommendations were provided to shops that included making improvements to ventilation, hygiene, use of personal protective equipment, and, if possible, avoidance of products containing the alpha-diketone flavoring chemicals. Future research is needed to evaluate the long-term health risks among workers in the vape shop retail industry and for e-cigarette use generally. Specific areas include further characterizing e-liquid constituents and emissions, evaluating ingredient health risks, evaluating the contributions of different routes of exposure (dermal, inhalation, and ingestion), and determining effective exposure mitigation measures.

New Analytical Method for Quantifying Flavoring Chemicals of Potential Respiratory Health Risk Concerns in e-Cigarette Liquids

Numerous flavoring chemicals are added to e-cigarette liquids to create various flavors. Flavorings provide sensory experience to users and increase product appeal; however, concerns have been raised about their potential inhalation toxicity. Estimating potential health risk of inhaling these chemicals has been challenging since little is known about their actual concentrations in e-cigarette products. To date, a limited number of analytical methods exist to measure the concentrations of flavoring chemicals in e-cigarette products. We have developed an analytical method that accurately and precisely measures the concentrations of 20 flavoring chemicals of potential inhalation risk concerns: 2,3,5-trimethylpyrazine, acetoin, benzaldehyde, benzyl alcohol, butanoic acid, dl-limonene, ethyl maltol, ethyl salicylate, ethyl vanillin, eucalyptol, eugenol, furaneol, isovanillin, l-menthol, maltol, methyl salicylate, pulegone, trans-cinnamaldehyde, triacetin, and vanillin. Calibration and QC solutions were prepared in 50:50 propylene glycol (PG):vegetable glycerin (VG) and 5% H₂O and flavoring concentrations ranging from 0.02 to 10.00 mg/ml. Samples of commercial e-cigarette liquids, calibration and QC solutions were combined with 30 µL of an internal standard mix (benzene-d6, pyridine-d5, chlorobenzene-d5, naphthalene-d8 and acenaphthene-d10; 1 mg/ml each) and were diluted 100-fold into methanol. Analysis was performed on an Agilent 7890B/7250 GC/Q-TOF using a DB-624UI column (30 m x 0.25 mmID x 1.4 μm film thickness), with a total runtime of 13.5 min. Calibration curves were fit using a weighted quadratic model and correlations of determination (r²) values exceeded 0.990 for all chemicals. Bias and precision tests yielded values less than 20% and lower limits of quantitation (LLOQ) ranged from 0.02 to 0.63 mg/ml. Over 200 commercially available products, purchased or collected from adult e-cigarette users and spanning a range of flavor categories, were evaluated with this method. Concentrations of pulegone, a suspected carcinogen, varied from below limit of quantitation (BLOQ) to 0.32 mg/ml, while acetoin and vanillin, known precursors to more cytotoxic byproducts, ranged from BLOQ to 1.52 mg/ml and from BLOQ to 16.22 mg/ml, respectively. This method features a wide dynamic working range and allows for a rapid routine analysis of flavoring additives in commercial e-cigarette liquids.

Effects of E-Cigarette Refill Liquid Flavorings with and without Nicotine on Human Retinal Pigment Epithelial Cells: A Preliminary Study

Smoking is an etiologic factor for age-related macular degeneration (AMD). Although cigarette smoke has been extensively researched for retinal pigment epithelial (RPE) cell degeneration, the potential for adverse effects on the retinal epithelium following exposure to flavored e-cigarette refill liquid has never been explored. In this preliminary study, we have examined the effects of 20 e-liquids (10 different flavored nicotine-free and 10 nicotine-rich e-liquids) used in e-cigarettes on the metabolic activity, membrane integrity, and mitochondrial membrane potential of RPE cells. Our results showed that of the flavors studied over the concentration range: 0.5, 1, and 2% v/v for a duration of 48 h, cinnamon was the most toxic and menthol was the second most toxic, while other flavors showed lesser or no cytotoxicity. The presence of nicotine augmented cytotoxicity for cinnamon, menthol, strawberry, vanilla, and banana while for other flavors there was no synergism. Together, our results demonstrate that exposure of RPE to flavored e-cigarette refill liquids caused significant cytotoxicity and may be a risk factor for the development of retinal pathogenesis, although further in-depth studies are necessary.

Effects of E-Cigarette Flavoring Chemicals on Human Macrophages and Bronchial Epithelial Cells

E-cigarettes utilize a wide range of flavoring chemicals with respiratory health effects that are not well understood. In this study, we used pulmonary-associated cell lines to assess the in vitro cytotoxic effects of 30 flavoring chemicals. Human bronchial epithelial cells (BEAS-2B) and both naïve and activated macrophages (THP-1) were treated with 10, 100, and 1000 µM of flavoring chemicals and analyzed for changes in viability, cell membrane damage, reactive oxygen species (ROS) production, and inflammatory cytokine release. Viability was unaffected for all chemicals at the 10 and 100 µM concentrations. At 1000 µM, the greatest reductions in viability were seen with decanal, hexanal, nonanal, cinnamaldehyde, eugenol, vanillin, alpha-pinene, and limonene. High amounts of ROS were elicited by vanillin, ethyl maltol, and the diketones (2,3-pentanedione, 2,3-heptanedione, and 2,3-hexanedione) from both cell lines. Naïve THP-1 cells produced significantly elevated levels of IL-1β, IL-8, and TNF-α when exposed to ethyl maltol and hexanal. Activated THP-1 cells released increased IL-1β and TNF-α when exposed to ethyl maltol, but many flavoring chemicals had an apparent suppressive effect on inflammatory cytokines released by activated macrophages, some with varying degrees of accompanying cytotoxicity. The diketones, L-carvone, and linalool suppressed cytokine release in the absence of cytotoxicity. These findings provide insight into lung cell cytotoxicity and inflammatory cytokine release in response to flavorings commonly used in e-cigarettes.

Effects of Carriers on Spray-dried Flavors and Their Functional Characteristics

BACKGROUND AND OBJECTIVE

Encapsulation is an effective method to keep the quality of and avoid changes in flavors or essential oils due to oxidation, heating, volatilization, or chemical interactions. This study aims to microencapsulate key flavorings by traditional wall materials, namely, gum arabic (GA), maltodextrin (MD) and sodium caseinate (SC) and evaluate the effects of different wall materials on the properties of the flavor microcapsules.

MATERIALS AND METHODS

The emulsions of flavor compounds (linalool, citral, orange oil, allyl caproate and isoamyl acetate) were prepared using GA, SC and MD as carriers with different concentrations and then encapsulated in powder form by a spray dryer. Physical properties, including encapsulation efficiency, viscosity, emulsion stability and moisture, were studied before and after the spray drying process. Moreover, the morphology and extent of the nonenzymatic browning (NEB) of powder particles were performed using a scanning electron microscope (SEM) and a chroma meter. The effect of encapsulation on flavor retention and chemical composition was evaluated using gas chromatography-mass spectrometry (GC-MS).

RESULTS

Orange oil shows the maximum retention efficiency (84.5-97.9%), whereas isoamyl acetate is less retained during drying (44.4-72.5%) compared with other volatile compounds. Increasing the concentration of GA provides the highest retention for all aroma compounds and improves the viscosity and the emulsion stability of spray-dried powder. The presence of MD as the main encapsulating agent enables the formation of several homogeneous capsules with a good spherical shape and a smooth surface, according to SEM. The NEB is observed intensively in encapsulated samples containing citral and orange oils, whereas the least browning occurs in isoamyl acetate microcapsules.

CONCLUSION

Wall material formulation affects the retention, morphology and physical properties of the encapsulated flavors, which can be used in food or nutraceutical powder premixes.

Acute Effect of Electronic Cigarette-Generated Aerosol From Flavored CBD-Containing Refill Solutions on Human Bronchial Epithelial Cells

Introduction: Although electronic cigarettes (e-cigarettes) were originally developed to deliver aerosolized nicotine to lungs, recent data have shown that consumers also use them for inhalation of other drugs, including cannabidiol (CBD). The aim of this study was to test the acute inhalation toxicity of flavored CBD-containing aerosols emitted from e-cigarettes. Methods: Bronchial epithelial cells (H292) cells were exposed to aerosol generated from e-cigarettes refilled either with (1) propylene glycol solvent only (PG, control), (2) commercially purchased unflavored solution with CBD, or (3) commercially purchased solutions with and without CBD and with different flavors. The in vitro toxicological effects were assessed using the following methods: (1) trypan blue exclusion assay (cell viability), (2) neutral red uptake assay (metabolic activity), and (3) ELISA (concentrations of inflammatory mediators). Results: Most flavored products with or without CBD were cytotoxic as compared to the air control. Overall, aerosols with CBD were more cytotoxic than aerosols without CBD irrelevant of the flavoring used in the product. Although, unflavored aerosols containing CBD in PG were significantly more cytotoxic than aerosols containing only PG, not all flavored products containing CBD were significantly more toxic than the same flavored products without CBD. Most CBD containing products significantly increase the concentration of cytokines released as compared to the same flavored products without CBD. Conclusion: Different flavors show different cytotoxic effects in CBD-containing e-cigarettes. Aerosols emitted from CBD containing e-cigarettes were more cytotoxic than those emitted from CBD-free e-cigarettes.

[Study on the development of measures to manage the risks associated with the food produced using microbial synthesis]

In order to increase the efficiency of food production, micro-organisms are used whose genetic material has been modified by directed mutagenesis or by transgenesis. Such products belong to a new type of products, the mandatory condition for the use of which is to confirm its safety when used in food. The aim of the article - justification of the need to improve the system for assessing the safety of foods obtained by microbial synthesis. Material and methods. The analysis and generalization of current scientific researches published in the databases Scopus, Web of Science, PubMed, RSCI, as well as national and international regulatory and legislative documents have been carried out. Results and discussion. The analysis of scientific data, legislative and regulatory documents of international legislation, the European Union, as well as other economically developed countries, has shown that a mandatory element of assessing the possibility of safe use of food produced by microbial synthesis is the study of the sequence of transgenic insert nucleotides in the producer strain in order to analyze the presence of pathogenicity determinants, antibiotic resistance, and the ability to produce toxic metabolites. The data obtained in vitro on the absence of risks of using both producer strains and the enzyme preparations and other ingredients synthesized by them in the food industry should be confirmed in experiments in vivo. Currently, the need to comply with these requirements, as well as the main criteria for assessing the risks of such food, are mainly provided by legislation and regulations of the Russian Federation. At the same time, the system of sanitary and hygienic assessment of the safety of producer strains and food ingredients produced by them needs to be updated.

Flavorings-Related Lung Disease: A Brief Review and New Mechanistic Data

Flavorings-related lung disease is a potentially disabling and sometimes fatal lung disease of workers making or using flavorings. First identified almost 20 years ago in microwave popcorn workers exposed to butter-flavoring vapors, flavorings-related lung disease remains a concern today. In some cases, workers develop bronchiolitis obliterans, a severe form of fixed airways disease. Affected workers have been reported in microwave popcorn, flavorings, and coffee production workplaces. Volatile α-dicarbonyl compounds, particularly diacetyl (2,3-butanedione) and 2,3-pentanedione, are implicated in the etiology. Published studies on diacetyl and 2,3-pentanedione document their ability to cause airway epithelial necrosis, damage biological molecules, and perturb protein homeostasis. With chronic exposure in rats, they produce airway fibrosis resembling bronchiolitis obliterans. To add to this knowledge, we recently evaluated airway toxicity of the 3-carbon α-dicarbonyl compound, methylglyoxal. Methylglyoxal inhalation causes epithelial necrosis at even lower concentrations than diacetyl. In addition, we investigated airway toxicity of mixtures of diacetyl, acetoin, and acetic acid, common volatiles in butter flavoring. At ratios comparable to workplace scenarios, the mixtures or diacetyl alone, but not acetic acid or acetoin, cause airway epithelial necrosis. These new findings add to existing data to implicate α-dicarbonyl compounds in airway injury and flavorings-related lung disease.

Environmental characterization of a coffee processing workplace with obliterative bronchiolitis in former workers

Obliterative bronchiolitis in five former coffee processing employees at a single workplace prompted an exposure study of current workers. Exposure characterization was performed by observing processes, assessing the ventilation system and pressure relationships, analyzing headspace of flavoring samples, and collecting and analyzing personal breathing zone and area air samples for diacetyl and 2,3-pentanedione vapors and total inhalable dust by work area and job title. Mean airborne concentrations were calculated using the minimum variance unbiased estimator of the arithmetic mean. Workers in the grinding/packaging area for unflavored coffee had the highest mean diacetyl exposures, with personal concentrations averaging 93 parts per billion (ppb). This area was under positive pressure with respect to flavored coffee production (mean personal diacetyl levels of 80 ppb). The 2,3-pentanedione exposures were highest in the flavoring room with mean personal exposures of 122 ppb, followed by exposures in the unflavored coffee grinding/packaging area (53 ppb). Peak 15-min airborne concentrations of 14,300 ppb diacetyl and 13,800 ppb 2,3-pentanedione were measured at a small open hatch in the lid of a hopper containing ground unflavored coffee on the mezzanine over the grinding/packaging area. Three out of the four bulk coffee flavorings tested had at least a factor of two higher 2,3-pentanedione than diacetyl headspace measurements. At a coffee processing facility producing both unflavored and flavored coffee, we found the grinding and packaging of unflavored coffee generate simultaneous exposures to diacetyl and 2,3-pentanedione that were well in excess of the NIOSH proposed RELs and similar in magnitude to those in the areas using a flavoring substitute for diacetyl. These findings require physicians to be alert for obliterative bronchiolitis and employers, government, and public health consultants to assess the similarities and differences across the industry to motivate preventive intervention where indicated by exposures above the proposed RELs for diacetyl and 2,3-pentanedione.

Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release

With increased awareness of the health benefits of the compounds in green tea, especially polyphenols, its consumption is rising. The main purpose of this study is to determine the effect of different additives on the released fluoride into tea liquor and also daily fluoride intake. The concentrations of fluoride, nitrate, sulfate, and chloride were measured in 15 different flavored green teas (Refah-Lahijan). The fluoride and other anion concentrations were measured by ion chromatography method. The data were analyzed with Statistical Package for the Social Sciences version 16.0. The results showed that the minimum and maximum concentrations of fluoride in the green tea infusions were 0.162 mg/L (cinnamon-flavored green tea) and 3.29 mg/L (bagged peach-flavored green tea), respectively. The mean concentration of fluoride in the green tea leaves was 52 mg/kg, and approximately 89% of the fluoride was released from the green tea leaves into the infusions after brewing. The fluoride concentrations varied significantly among the examined green teas (P < 0.05). However, the additives had no significant effect on the fluoride release into the infusions (P > 0.05). Finally, drinking of the studied green teas cannot make a significant contribution to the daily dietary intake of F for consumers.

Respiratory morbidity in a coffee processing workplace with sentinel obliterative bronchiolitis cases

RATIONALE

Obliterative bronchiolitis in former coffee workers prompted a cross-sectional study of current workers. Diacetyl and 2,3-pentanedione levels were highest in areas for flavoring and grinding/packaging unflavored coffee.

METHODS

We interviewed 75 (88%) workers, measured lung function, and created exposure groups based on work history. We calculated standardized morbidity ratios (SMRs) for symptoms and spirometric abnormalities. We examined health outcomes by exposure groups.

RESULTS

SMRs were elevated 1.6-fold for dyspnea and 2.7-fold for obstruction. The exposure group working in both coffee flavoring and grinding/packaging of unflavored coffee areas had significantly lower mean ratio of forced expiratory volume in 1 s to forced vital capacity and percent predicted mid-expiratory flow than workers without such exposure.

CONCLUSION

Current workers have occupational lung morbidity associated with high diacetyl and 2,3-pentanedione exposures, which were not limited to flavoring areas.

Flavoring exposure in food manufacturing

Flavorings are substances that alter or enhance the taste of food. Workers in the food-manufacturing industry, where flavorings are added to many products, may be exposed to any number of flavoring compounds. Although thousands of flavoring substances are in use, little is known about most of these in terms of worker health effects, and few have occupational exposure guidelines. Exposure assessment surveys were conducted at nine food production facilities and one flavor manufacturer where a total of 105 area and 74 personal samples were collected for 13 flavoring compounds including five ketones, five aldehydes, and three acids. The majority of the samples were below the limit of detection (LOD) for most compounds. Diacetyl had eight area and four personal samples above the LOD, whereas 2,3-pentanedione had three area samples above the LOD. The detectable values ranged from 25-3124 ppb and 15-172 ppb for diacetyl and 2,3-pentanedione respectively. These values exceed the proposed National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit for these compounds. The aldehydes had the most detectable samples, with each of them having >50% of the samples above the LOD. Acetaldehyde had all but two samples above the LOD, however, these samples were below the OSHA PEL. It appears that in the food-manufacturing facilities surveyed here, exposure to the ketones occurs infrequently, however levels above the proposed NIOSH REL were found. Conversely, aldehyde exposure appears to be ubiquitous.

Determination of four flavorings in infant formula by solid-phase extraction and gas chromatography-tandem mass spectrometry

Increasing attention has been focused on the artificial flavorings added in foods, especially those for infants and children. For the first time, a sensitive and efficient analytical method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous identification and quantification of four flavoring agents (vanillin, methylvanillin, ethylvanillin, and coumarin) in infant formula samples. The flavorings in samples were extracted with methanol/water (v/v, 1:1), cleaned up by solid-phase extraction, and determined by GC-MS/MS in selected reaction monitoring (SRM) mode. Both isotope-labeled internal standards and matrix-matched calibration solutions were used to correct the matrix effects. The limit of quantification (LOQ) was calculated as 10 times the standard deviation, and it was 10.0 μg kg (-1) for vanillin, methylvanillin, ethylvanillin, and coumarin. The average recoveries were in the range of 82.8-107.5% with relative standard deviations (RSDs) below 8.9% measured at three concentration levels (10, 50, and 100 μg kg(-1)). The proposed method is suitable for the sensitive and accurate simultaneous determination of four flavoring agents in infant formula samples and also provided potential use for reference in terms of real analysis of other foods.

Respiratory symptoms and lung function abnormalities related to work at a flavouring manufacturing facility

OBJECTIVES

To better understand respiratory symptoms and lung function in flavouring manufacturing workers.

METHODS

We offered a questionnaire and lung function testing to the current workforce of a flavouring manufacturing facility that had transitioned away from diacetyl and towards substitutes in recent years. We examined symptoms, spirometric parameters and diffusing capacity measurements by exposure variables, including facility tenure and time spent daily in production areas. We used linear and logistic regression to develop final models adjusted for age and smoking status.

RESULTS

A total of 367 (93%) current workers participated. Shortness of breath was twice as common in those with tenure ≥ 7 years (OR 2.0, 95% CI 1.1 to 3.6). Other chest symptoms were associated with time spent daily in production. Participants who spent ≥ 1 h daily in production areas had twice the odds of any spirometric abnormality (OR 2.3; 95% CI 1.1 to 5.3) and three times the odds of low diffusing capacity (OR 2.8; 95% CI 0.9 to 9.4) than other participants. Mean spirometric parameters were significantly lower in those with tenure ≥ 7 years and those who spent ≥ 1 h daily in production. Mean diffusing capacity parameters were significantly lower in those with tenure ≥ 7 years. Differences in symptoms and lung function could not be explained by age, smoking status or employment at another flavouring plant.

CONCLUSIONS

Symptoms and lung function findings were consistent with undiagnosed or subclinical obliterative bronchiolitis and associated with workplace exposures. Further efforts to lower exposures to flavouring chemicals, including diacetyl substitutes, are warranted.

Work-related spirometric restriction in flavoring manufacturing workers

BACKGROUND

Flavoring-exposed workers are at risk for occupational lung disease.

METHODS

We examined serial spirometries from corporate medical surveillance of flavoring production workers to assess abnormality compared to the U.S. population; mean decline in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC); and excessive declines in FEV1.

RESULTS

Of 106 workers, 30 had spirometric restriction, 3 had obstruction, 1 had both, and 13 (of 70, 19%) had excessive declines in FEV1. The adjusted prevalence of restriction was 3.7 times expected. Employees with higher potential for flavorings exposure had 3.0 times and 2.4 times greater average annual declines in FEV1 and FVC respectively, and had 5.8 times higher odds of having excessive FEV1 declines than employees with lower potential for exposure.

CONCLUSION

Exposure-related spirometric abnormalities consistent with a restrictive process evolved during employment, suggesting that exposures in flavoring production are associated with a range of pathophysiology.

Diacetyl increases sensory innervation and substance P production in rat trachea

Inhalation of diacetyl, a butter flavoring, causes airway responses potentially mediated by sensory nerves. This study examines diacetyl-induced changes in sensory nerves of tracheal epithelium. Rats (n = 6/group) inhaled 0-, 25-, 249-, or 346-ppm diacetyl for 6 hr. Tracheas and vagal ganglia were removed 1-day postexposure and labeled for substance P (SP) or protein gene product 9.5 (PGP9.5). Vagal ganglia neurons projecting to airway epithelium were identified by axonal transport of fluorescent microspheres intratracheally instilled 14 days before diacetyl inhalation. End points were SP and PGP9.5 nerve fiber density (NFD) in tracheal epithelium and SP-positive neurons projecting to the trachea. PGP9.5-immunoreactive NFD decreased in foci with denuded epithelium, suggesting loss of airway sensory innervation. However, in the intact epithelium adjacent to denuded foci, SP-immunoreactive NFD increased from 0.01 ± 0.002 in controls to 0.05 ± 0.01 after exposure to 346-ppm diacetyl. In vagal ganglia, SP-positive airway neurons increased from 3.3 ± 3.0% in controls to 25.5 ± 6.6% after inhaling 346-ppm diacetyl. Thus, diacetyl inhalation increases SP levels in sensory nerves of airway epithelium. Because SP release in airways promotes inflammation and activation of sensory nerves mediates reflexes, neural changes may contribute to flavorings-related lung disease pathogenesis.