The influence of chemical degradation during dietary exposures to fish on biomagnification factors and bioaccumulation factors

2018 ◽  
Vol 20 (1) ◽  
pp. 86-97 ◽  
Author(s):  
Jon A. Arnot ◽  
Donald Mackay
Keyword(s):  
Absorption Efficiency ◽  
Chemical Degradation ◽  
Bioaccumulation Factors ◽  
Biomagnification Factors

The chemical dietary absorption efficiency (ED) quantifies the amount of chemical absorbed by an organism relative to the amount of chemical an organism is exposed to following ingestion.

A generic fluticasone propionate and salmeterol dry powder inhaler: Evidence of usability, function, and robustness

2021 ◽  
Vol 42 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Donald P. Tashkin ◽  
Arkady Koltun ◽  
Róisín Wallace
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Fluticasone Propionate ◽  
Healthy Volunteers ◽  
Pulmonary Disease ◽  
Dry Powder Inhaler ◽  
Chemical Degradation ◽  
Chronic Obstructive ◽  
Dry Powder ◽  
Obstructive Pulmonary Disease ◽  
Flow Rates

Background: A generic combination of fluticasone propionate and salmeterol xinafoate inhalation powder in a premetered, multidose, nonreusable inhaler was recently approved. Objective: To assess the performance of the generic device. Methods: Findings from three studies with regard to device usability, function, and robustness were reviewed. Results: In a study to assess device function in patients and healthy volunteers, the generic device was successfully used by patients with asthma and chronic obstructive pulmonary disease who were either dry powder inhaler users or dry powder inhaler‐naive, even though they were not trained beyond being provided the instructions for use. In a study to measure inhaled flow rates generated by patients and healthy volunteers, the generic device consistently simulated the delivery of a full dose of drug, even to patients with severe respiratory disease and reduced inspiratory flow rates. Although the generic device had a slightly higher airflow resistance, this study demonstrated that this difference did not result in any clinically meaningful differences in terms of drug delivery. Pressure drop, a key parameter that drives the fluidization and aerosolization of the powder dose, was found to be comparable between the devices. In an open-label study, the generic device met all U.S. Food and Drug Administration specifications for device robustness after 21.5 days of twice-daily dosing via oral inhalation among 111 participants with asthma or chronic obstructive pulmonary disease. All inhalers tested demonstrated conformity with a pharmacopeia with respect to key quality parameters (assay, delivered dose uniformity, aerodynamic size distribution). There was no evidence of chemical degradation of the active ingredients, nor of microbial or water ingress into the powder, as a result of inhaler use.

Mechanism of Perfluorsulfonic Acid Membrane Chemical Degradation Under Low RH Conditions

2013 ◽  
Vol 50 (2) ◽  
pp. 907-918 ◽  
Author(s):  
F. D. Coms ◽  
H. Xu ◽  
T. McCallum ◽  
C. Mittelsteadt
Keyword(s):  
Chemical Degradation

scholarly journals Optimization of Tilmicosin-Loaded Nanostructured Lipid Carriers Using Orthogonal Design for Overcoming Oral Administration Obstacle

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 303
Author(s):  
Jia Wen ◽  
Xiuge Gao ◽  
Qian Zhang ◽  
Benazir Sahito ◽  
Hongbin Si ◽  
...  
Keyword(s):  
Oral Administration ◽  
Oral Delivery ◽  
Bacterial Infections ◽  
Cold Water ◽  
Orthogonal Design ◽  
Drug Loading ◽  
Absorption Efficiency ◽  
Nanostructured Lipid Carriers ◽  
Orthogonal Experimental Design ◽  
Hydrodynamic Diameter

Tilmicosin (TMS) is widely used to treat bacterial infections in veterinary medicine, but the clinical effect is limited by its poor solubility, bitterness, gastric instability, and intestinal efflux transport. Nanostructured lipid carriers (NLCs) are nowadays considered to be a promising vector of therapeutic drugs for oral administration. In this study, an orthogonal experimental design was applied for optimizing TMS-loaded NLCs (TMS-NLCs). The ratios of emulsifier to mixed lipids, stearic acid to oleic acid, drugs to mixed lipids, and cold water to hot emulsion were selected as the independent variables, while the hydrodynamic diameter (HD), drug loading (DL), and entrapment efficiency (EE) were the chosen responses. The optimized TMS-NLCs had a small HD, high DL, and EE of 276.85 ± 2.62 nm, 9.14 ± 0.04%, and 92.92 ± 0.42%, respectively. In addition, a low polydispersity index (0.231 ± 0.001) and high negative zeta potential (−31.10 ± 0.00 mV) indicated the excellent stability, which was further demonstrated by uniformly dispersed spherical nanoparticles under transmission electron microscopy. TMS-NLCs exhibited a slow and sustained release behavior in both simulated gastric juice and intestinal fluid. Furthermore, MDCK-chAbcg2/Abcb1 cell monolayers were successfully established to evaluate their absorption efficiency and potential mechanism. The results of biodirectional transport showed that TMS-NLCs could enhance the cellular uptake and inhibit the efflux function of drug transporters against TMS in MDCK-chAbcg2/Abcb1 cells. Moreover, the data revealed that TMS-NLCs could enter the cells mainly via the caveolae/lipid raft-mediated endocytosis and partially via macropinocytosis. Furthermore, TMS-NLCs showed the same antibacterial activity as free TMS. Taken together, the optimized NLCs were the promising oral delivery carrier for overcoming oral administration obstacle of TMS.

Preparation and characterisation of liquid epoxidised natural rubber in latex stage by chemical degradation

2021 ◽  
Author(s):  
Nurul Hayati Yusof ◽  
Dazylah Darji ◽  
Fatimah Rubaizah Mohd Rasdi ◽  
Krishna Veni Baratha Nesan
Keyword(s):  
Natural Rubber ◽  
Chemical Degradation

scholarly journals Rational Design and Simulation of Two-Dimensional Perovskite Photonic Crystal Absorption Layers Enabling Improved Light Absorption Efficiency for Solar Cells

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2460
Author(s):  
Jian Zou ◽  
Mengnan Liu ◽  
Shuyu Tan ◽  
Zhijie Bi ◽  
Yong Wan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solar Cells ◽  
Photonic Crystal ◽  
Incident Light ◽  
Absorption Efficiency ◽  
Utilization Efficiency ◽  
Photonic Crystal Structure ◽  
Two Dimensional ◽  
Photoelectric Conversion ◽  
Absorption Layer

A two-dimensional perovskite photonic crystal structure of Methylamine lead iodide (CH3NH3PbI3, MAPbI3) is rationally designed as the absorption layer for solar cells. The photonic crystal (PC) structure possesses the distinct “slow light” and band gap effect, leading to the increased absorption efficiency of the absorption layer, and thus the increased photoelectric conversion efficiency of the battery. Simulation results indicate that the best absorption efficiency can be achieved when the scattering element of indium arsenide (InAs) cylinder is arranged in the absorption layer in the form of tetragonal lattice with the height of 0.6 μm, the diameter of 0.24 μm, and the lattice constant of 0.4 μm. In the wide wavelength range of 400–1200 nm, the absorption efficiency can be reached up to 82.5%, which is 70.1% higher than that of the absorption layer without the photonic crystal structure. In addition, the absorption layer with photonic crystal structure has good adaptability to the incident light angle, presenting the stable absorption efficiency of 80% in the wide incident range of 0–80°. The results demonstrate that the absorption layer with photonic crystal structure can realize the wide spectrum, wide angle, and high absorption of incident light, resulting in the increased utilization efficiency of solar energy.

Enhanced Skin Permeation of Punicalagin after Topical Application of Pluronic Micelles or Vesicles Loaded with Lafoensia pacari Extract

Planta Medica ◽  
2021 ◽  
Author(s):  
Sandra Alves de Sousa Garcia ◽  
Priscila Bianca Rodrigues da Rocha ◽  
Bruno dos Santos Souza ◽  
Andressa Tuane Santana Paz ◽  
Ana Luiza Caetano Negris ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Skin Permeation ◽  
Sol Gel ◽  
Extraction Procedure ◽  
Average Diameter ◽  
Skin Aging ◽  
Chemical Degradation ◽  
Vertical Diffusion ◽  
Flowing Liquid ◽  
Span 80

AbstractPunicalagin, the principal ellagitannin of Lafoensia pacari leaves, has proven antioxidant activity, and standardized extracts of L. pacari can be topically used for skin aging management. We hypothesized that Pluronic nanomicelles or vesicles could solubilize sufficiently large amounts of the standardized extracts of L. pacari and provide chemical stability to punicalagin. The standardized extracts of L. pacari were obtained with an optimized extraction procedure, and the antioxidant activity was characterized. Formulations containing Pluronic at 25% and 35% were obtained with or without Span 80. They were characterized by average diameter, polydispersity index, punicalagin content, physicochemical stability, and rheology. A release and skin permeation study was carried out in vertical diffusion cells. The extraction procedure allowed quantifying high punicalagin content (i.e., 141.61 ± 3.87 mg/g). The standardized extracts of L. pacari showed antioxidant activity for all evaluated methods. Pluronic at 25 and Pluronic at 35 with standardized extracts of L. pacari showed an average diameter of about 25 nm. The addition of Span 80 significantly increased the mean diameter by 15-fold (p < 0.05), indicating the spontaneous formation of vesicles. Pluronic formulations significantly protected punicalagin from chemical degradation (p < 0.05). Pluronic at 25 formulations presented as free-flowing liquid-like systems, while Pluronic at 35 resulted in an increase of about 44-fold in |ƞ*|. The addition of Span 80 significantly reduced the Pluronic sol-gel transition temperature (p < 0.05), indicating the formation of vesicles. Formulations with Span 80 significantly enhanced punicalagin skin permeation compared to formulations without Span 80 (p < 0.05). Formulations with Span 80 were demonstrated to be the most promising formulations, as they allowed significant permeation of punicalagin (about 80 to 315 µg/cm2), which has been shown to have antioxidant activity.

Sign in / Sign up

Export Citation Format

Share Document