Relevant bibliographies by topics / HFA-134a

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  2. Dissertations / Theses
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  4. Conference papers

Academic literature on the topic 'HFA-134a'

Author: Grafiati
Published: 4 June 2021
Last updated: 8 February 2022

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Journal articles on the topic "HFA-134a"

1

Harrison, Lester I. "PHARMACOKINETICS OF HFA-134a." American Journal of Therapeutics 3, no. 11 (November 1996): 763–65. http://dx.doi.org/10.1097/00045391-199611000-00005.

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2

Alexander, DJ, SE Libretto, MJ Adams, EW Hughes, and M. Bannerman. "HFA-134a (1,1,1,2-tetrafluoroethane): effects of inhalation exposure upon reproductive performance, development and maturation of rats." Human & Experimental Toxicology 15, no. 6 (June 1996): 508–17. http://dx.doi.org/10.1177/096032719601500609.

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1 HFA-134a was administered to AHA rats by snout-only inhalation for 1 h daily to assess the effects of treatment on reproduction and development. 2 In a fertility study, rats were exposed to atmospheres of 2500, 10000 or 50000 p.p.m. HFA-134a throughout gametogenesis, mating, pregnancy and lactation. 3 In a peri- and post-natal study, rats were exposed to HFA-134a from days 17 to 20 of pregnancy and days 1 to 21 post partum to atmospheres of 1800, 9900 or 64 400 p.p.m. 4 The only treatment-related effect was a slight reduc tion in body weight gain of males of the treated parental generation at 50 000 p.p.m. (fertility study). 5 In neither study were there any adverse effects of HFA- 134a on the reproductive performance of treated animals or on the development, maturation or reproductive performance of up to two successive generations.
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Alexander, DJ, SE Libretto, H.-J. Chevalier, T. Imamura, G. Pappritz, and J. Wilson. "HFA-134a (1 ,1, 1, 2-tetrafluoroethane): lack of oncogenicity in rodents after inhalation." Human & Experimental Toxicology 14, no. 9 (September 1995): 706–14. http://dx.doi.org/10.1177/096032719501400902.

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1 Groups of 60 male and 60 female B6C3F1 mice or Han- Ibm Wistar rats were exposed to HFA-134a using snout- only inhalation exposure techniques for periods of one hour daily for at least 104 weeks. HFA-134a was deliv ered directly from cylinders at vapour concentrations of 2500, 15 000 and 75 000ppm for mice and from metered-dose inhalers at vapour concentrations of 2500, 10 000 and 50 000ppm for rats. 2 Intended dosages were achieved. 3 Evidence of absorption was found at each dose level and was dose related. 4 Neither species suffered any treatment related effects on survival, clinical signs, body weights, haematology nor on the type, incidence, site or severity of gross lesions. 5 There was no effect of treatment on the type, incidence, site or severity of neoplasms in mice or rats. 6 There were no non-neoplastic findings related to treat ment in mice. 7 HFA-134a was considered not to be oncogenic and to provide a safe alternative to chlorofluorocarbons for use in pharmaceutical metered-dose inhalers.
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Lyttle, Brian, John Gillies, Maarja Panov, Andrzej Emeryk, and Claire Wixon. "Fluticasone Propionate, 100 µg bid, Using a Non-CFC Propellant, HFA 134a, in Asthmatic Children." Canadian Respiratory Journal 10, no. 2 (2003): 103–9. http://dx.doi.org/10.1155/2003/627531.

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BACKGROUND: Secondary to phasing out chlorofluorocarbons (CFCs), the fluticasone propionate (FP) pressurized metered-dose inhaler has been formulated in a nonozone-depleting propellant, hydrofluoralkane (HFA) 134a.OBJECTIVES: To demonstrate equivalent efficacy and safety of FP 200 µg daily propelled by HFA 134a to FP 200 µg daily propelled by CFCs 11 and 12 over a four-week treatment period in pediatric asthmatic patients.METHODS: The study was multinational, randomized, double blind and of parallel group design. Eligible patients aged 16 years and younger were steroid naive or receiving 500 µg/day or less of beclomethasone dipropionate, budesonide or flunisolide, or 250 µg/day or less of inhaled FP. The primary efficacy variable was mean morning peak expiratory flow with equivalence determined if the 90% CIs for the treatment differences between groups were within ±15 L/min.RESULTS: Three hundred fifteen patients (mean age 9.3±2.8 years) were randomly assigned; 158 patients received FP HFA 134a and 157 patients received FP CFC. Over the four-week treatment period, mean morning peak expiratory flow increased from baseline in both groups (14 L/min and 17 L/min, respectively), with a mean treatment difference of -2 L/min. Equivalence was demonstrated between the groups (90% CI -6 to +3 L/min; P=0.589). Both formulations were well tolerated with no serious drug-related events.CCONCLUSIONS: FP propelled by HFA 134a has equivalent efficacy and comparable safety to FP propelled by CFC propellants at a microgram equivalent dose in pediatric asthmatic patients.
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Alexander, DJ, and SE Libretto. "An overview of the toxicology of HFA-134a (1,1,1,2-tetrafluoroethane)." Human & Experimental Toxicology 14, no. 9 (September 1995): 715–20. http://dx.doi.org/10.1177/096032719501400903.

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1 This paper reviews the results of preclinical toxicology studies on HFA-134a carried out by Glaxo Research and Development Ltd. 2 A comprehensive range of studies was conducted in ani mal models suitable for the type of investigation. 3 The inhalation route of administration was used in all in vivo studies (with the exception of local tolerance and sensitisation studies) as patients will be exposed only to vapour during actuation of metered-dose inhalers. Cell cultures used for in vitro studies were also exposed to the vapour. 4 There was no mortality of rodents or dogs at extremely high vapour concentrations (81%v/v). 5 HFA-134a was considered not to be toxic or oncogenic and to provide a safe alternative to chlorofluorocarbons for use in pharmaceutical metered-dose inhalers.
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Harris, Julie A., Michael D. Carducci, and Paul B. Myrdal. "Beclomethasone dipropionate crystallized from HFA-134a and ethanol." Acta Crystallographica Section E Structure Reports Online 59, no. 11 (October 7, 2003): o1631—o1633. http://dx.doi.org/10.1107/s1600536803021196.

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7

Boulet, Louis-Philippe, André Cartier, Pierre Ernst, Pierre Larivée, and Michel Laviolette. "Safety and Efficacy of HFA-134a Beclomethasone Dipropionate Extra-Fine Aerosol over Six Months." Canadian Respiratory Journal 11, no. 2 (2004): 123–30. http://dx.doi.org/10.1155/2004/823084.

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OBJECTIVE: To compare the systemic safety and efficacy of hydrofluoroalkane beclomethasone dipropionate (HFA-BDP) extra-fine aerosol 800 µg/day with chlorofluorocarbon (CFC)-BDP 1500 µg/day.DESIGN: Six-month, randomized, parallel-group, double-blind, double-dummy study.PATIENTS: Patients (n=141) with moderate to severe asthma adequately controlled by CFC-BDP 1000 µg/day to 2000 µg/day.INTERVENTIONS: Patients received CFC-BDP 1500 µg/day during a two-week run-in period and were then randomized to either HFA-BDP (n=70) or CFC-BDP (n=71).RESULTS: Similar proportions of HFA-BDP and CFC-BDP patients had a 24 h urinary free cortisol values below the reference range at month 6 (15% versus 25%, P=0.35). Measures of adrenocorticotrophic hormone stimulation and morning plasma cortisol levels were also similar in each group. The frequency of skin bruising and oral candidiasis was low for both treatments. No change in intraocular pressure was reported for either treatment. Pulmonary function was similar in both groups; however, the onset of the first asthma exacerbation or increased asthma symptoms tended to be earlier for CFC-BDP than for HFA-BDP (P=0.076); 27% of CFC-BDP patients reported increased asthma symptoms, compared with 14% of HFA-BDP patients (P=0.095).CONCLUSIONS: HFA-BDP 800 µg/day has a systemic adverse event profile comparable to that of CFC-BDP 1500 µg/day, and further control of asthma symptoms may be achieved after a switch from CFC-BDP 1500 µg/day to HFA-BDP 800 µg/day.
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Williams III, R. O., and Jie Liu. "Formulation of a protein with propellant HFA 134a for aerosol delivery." European Journal of Pharmaceutical Sciences 7, no. 2 (January 1999): 137–44. http://dx.doi.org/10.1016/s0928-0987(98)00015-3.

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Hoye, Julie A., and Paul B. Myrdal. "Measurement and correlation of solute solubility in HFA-134a/ethanol systems." International Journal of Pharmaceutics 362, no. 1-2 (October 2008): 184–88. http://dx.doi.org/10.1016/j.ijpharm.2008.06.020.

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Finch, John R., William R. Banks, Dah-ren Hwang, Martin R. Satter, Bilal Ezzidene, Joseph C. Mantil, and George A. Digenis. "Synthesis and in vivo disposition studies of 18F-labeled HFA-134a." Applied Radiation and Isotopes 46, no. 4 (April 1995): 241–48. http://dx.doi.org/10.1016/0969-8043(94)00129-n.

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Dissertations / Theses on the topic "HFA-134a"

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Hoye, Julie Annalisa. "An Investigation of Solute Solubility in the Propellant HFA-134a." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/196098.

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The reformulation of pressurized metered dose inhalers (MDIs) with hydrofluoroalkanes (HFAs) from chlorofluorocarbons (CFCs) has given rise to many solubility challenges. Compounds and excipients previously used in CFCs were observed to have significantly different solubility values in HFA-134a. In this investigation, the solubility values of solid organic solutes were determined in pure HFA-134a and HFA-134a with cosolvent (0 - 20% w/w ethanol). The solubilities of solid solutes in HFA-134a were also compared with those in 2H,3H-decafluoropentane (DFP) in order to assess the suitability of DFP as a liquid model propellant. The experimental set of solutes display diverse physico-chemical properties and yielded solubility values that ranged over four orders of magnitude. The experimental solubilities were compared to calculated values obtained from ideal solubility and regular solution theory models. While the theoretical models did not offer absolute solubility estimations, a clear correlation with the ideal solubility (melting point) was noted. Further consideration utilizing multiple linear regression models afforded correlations based on molecular properties. Regression models, containing melting point and logP (or molar volume) resulted in promising correlations in both pure HFA-134a and HFA-134a/cosolvent systems where the average absolute errors ranged from 0.49 to 0.82 log units, (average factor errors of 3.09 and 6.61, respectively). In general, a linear relationship was observed between log mole fraction solubility in HFA-134a and fraction ethanol. The effect on solubilization ranged from 1.3 to 99.4 times when 20% w/w ethanol was introduced, relative to pure HFA-134a. DFP appears to be a promising liquid model for pure HFA-134a for pre-formulation calculations. A two parameter equation were found to be significant in pure HFA-134a where the average absolute error (AAE) value was 0.61 log units (average factor errors of 4.07).
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Ludwig-Sengpiel, Andrea [Verfasser]. "Der Effekt von inhaliertem HFA-134a Beclometasondipropionat (Ventolair) auf Lymphozyten der bronchoalveolären Lavage (BAL) bei chronischer Sarkoidose / vorgelegt von Andrea Ludwig-Sengpiel." 2009. http://d-nb.info/1001490886/34.

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Book chapters on the topic "HFA-134a"

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Pike, Victor W., Richard J. N. Tanner, Franklin I. Aigbirhio, Christopher A. J. Freemantle, Stephen L. Waters, Brian C. Page, Christopher G. Rhodes, Per Olsson, G. Pietro Ventresca, and Terry Jones. "The Disposition of a New Drug Propellant (HFA 134a) in Humans Studied by Fluorine-18 Labelling and Whole-Body γ-Counting." In PET for Drug Development and Evaluation, 341–52. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0429-6_30.

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Conference papers on the topic "HFA-134a"

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Takeda, Tomoshi, Akio Niimi, Hisako Matsumoto, Isao Ito, Masafumi Yamaguchi, Hirofumi Matsuoka, Makiko Jinnai, et al. "Effect Of Hydrofluoroalkane-134a Beclomethasone (HFA-BDP) And Fluticasone Propionate Dry Powder Inhaler (FP-DPI) On Large And Small Airway Indices In Asthma: A Randomized Comprehensive Study." In American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado. American Thoracic Society, 2011. http://dx.doi.org/10.1164/ajrccm-conference.2011.183.1_meetingabstracts.a1290.

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Oliveira, Ricardo F., Manuel V. Silva, Ana V. Machado, Manuel Oliveira, Helena Maria Cabral-Marques, Senhorinha F. Teixeira, and José Carlos Teixeira. "Experimental Assessment of Emitted Dose From Valved Holding Chamber Devices." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38846.

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Due to the increasing worldwide incidence of asthma, a growing usage of inhalation devices has been observed. Some of the pressurized Metered Dose Inhalers (pMDI) limitations have been overcome by the introduction of newly and improved Valved Holding Chambers (VHC), resulting in good patient acceptance. The efficiency is assessed by the VHC Emitted Dose (ED), i.e. the amount of drug available to the patient. Using the pMDI salbutamol sulfate formulation (Ventolin® HFA-134a) as the test drug, several VHC devices were assessed. These latest were grouped by material characteristics: dissipative (OptiChamber Diamond®, AeroChamber Plus®, Vortex®, A2A Spacer®), non-dissipative (SpaceChamber Plus®, Compact SpaceChamber Plus®, Volumatic®) and stainless steel (Nebuchamber®). The pMDI + VHC were assembled to a filter housing, which comprises an induction port with similar USP Throat dimensions, and connected to a vacuum pump (calibrated at 15, 26 and 40 L/min). Using UV-Vis Spectrophotometry equipment at 244 nm, it was possible to determine its concentration for later mass calculation. For all the VHC devices tested, the total mass recovery percentage was between 85% and 120%. At 26 L/min, the Vortex® VHC has shown the highest ED (47.3 ± 1.8 %). The ED may not be dependent on the volume of the VHC. Although, further analysis of the results suggests the existence of a linear correlation between the ED and the VHC body length. SpaceChamber Plus® results show an increase of the ED and, subsequently, a decrease in VHC deposition fraction, with the increase of airflow.
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Oliveira, Ricardo F., Senhorinha F. Teixeira, Helena Maria Cabral Marques, and José Carlos Teixeira. "A Correlative CFD Study Between Recirculation Area and FPM in VHC Design." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67329.

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A major part of asthma treatment is made by the use of preventive inhalation drugs. The Pressurized Metered-Dose Inhalator (pMDI) has been the backbone device for this treatment, due to its simplicity, portability and widely acceptance. But no device comes without its limitations, and pMDI is hard to handle properly by elders and children < 5 years old, resulting in reduced amount of drug to the patient lungs. Add-on devices (e.g. spacers) were developed to mitigate the need for coordination and reduce the oral/throat deposition, namely the Valved Holding Chambers (VHC). These devices are incorporated with a one-way valve and a chamber that allows the spray droplets to rapidly reduce their size upon release on a stagnated and confined flow. The VHC main ability, in terms of efficiency, is to reduce the coarse fraction (i.e. particles with diameter > 4.7μm) of the plume by impaction and allow the fine fraction to be inhaled by the patient. The VHC geometry will play a very importance role in the entrapment of small drug particles (i.e. fine fraction). The hypothesis proposed by this study is that a small particle has more probability to be trapped in geometries with higher recirculation areas (and stagnation zones). These macro vortices will cause a particle with small Stokes number to be entrapped; to assess this hypothesis a numerical study was modelled. The numerical study was carried out on an idealized geometry of a VHC device, using a 2D axisymmetric approach. Different coordinates for a “corner” point, were tested. FLUENT® was used to obtain the unsteady numerical solution, meshes were generated using Meshing® software from ANSYS®. Once the flow field is stabilized (around 0.6s), a pMDI spray was injected into the domain during 0.1 seconds and the simulation continued until perform 4 seconds. The simulation takes into account the vaporization of the HFA-134a propellant present in the droplets of spray and a User Defined Function (UDF) for modeling the particle -wall interaction. The post-processing of the results included the calculation of the recirculation area and the Fine Particle Mass (FPM) that exits the domain. Results show that the percentage of recirculation area decreases linearly with the increase of axial position of the corner point, and rapidly increases with the radial displacement. FPM results are not so linear; nevertheless they show opposite behavior to the recirculation area. Additionally, results show that high recirculation area reduces the amount of FPM emitted. Data can be correlated through a power function (FPM = 101.805*Area−0.244; R2 = 0.460). Results are more strongly correlated for lower values of radial displacement. The results seem to corroborate the hypothesis that smaller particles tend to be entrapped by recirculation areas.
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