correlation between latex stability data determined by practical and colloid chemistry-based methods

2007 ◽  
pp. 180-194 ◽  
Author(s):  
J. P. Fischer ◽  
E. Nölken
Keyword(s):  
Colloid Chemistry ◽  
Stability Data

Bis(monoazacrown ethers) with an electron-donating substituent at the hinge: A pronounced participation of hydroxyl group in formation of sodium ion sandwich complexes

1989 ◽  
Vol 54 (4) ◽  
pp. 1043-1054 ◽  
Author(s):  
Jiří Závada ◽  
Juraj Koudelka ◽  
Petr Holý ◽  
Martin Bělohradský ◽  
Ivan Stibor
Keyword(s):  
Complex Formation ◽  
Sandwich Structure ◽  
Sodium Ion ◽  
Hydroxyl Group ◽  
Complex Stability ◽  
Sandwich Complexes ◽  
Sandwich Complex ◽  
Marked Enhancement ◽  
Stability Data ◽  
Potentiometric Data

Sodium ion complex formation has been investigated potentiometrically in four homologous bis(crown) series I-IV differing by the nature of substituent placed at the linking trimethylene chain (X = OH, OCH3, OCH2C6H5 and H respectively). A marked enhancement of the complex stability has been observed in the bis(crown) series I and attributed to participation of the lateral hydroxyl group in the sandwich complex formation. Evidence in support of the sandwich structure has been provided (i) by analysis of the potentiometric data indicating a 1:1 complex stoichiometry and (ii) by a comparison of the complex stability data from the bis(crown) series I with the corresponding values from related monocyclic ligand series V, VI and VII revealing a pronounced cooperation of both macrorings in the sodium ion-bis(crown) I complex formation.

scholarly journals Investigation of the Physical, Chemical and Microbiological Stability of Losartan Potassium 5 mg/mL Extemporaneous Oral Liquid Suspension

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 301
Author(s):  
Lisa Foley ◽  
Jennifer Toney ◽  
James W. Barlow ◽  
Maura O’Connor ◽  
Deirdre Fitzgerald-Hughes ◽  
...  
Keyword(s):  
Shelf Life ◽  
Storage Conditions ◽  
Losartan Potassium ◽  
Microbial Count ◽  
E Coli ◽  
Physical Chemical ◽  
Liquid Suspension ◽  
Oral Liquid ◽  
Microbiological Stability ◽  
Stability Data

Extemporaneous oral liquid preparations are commonly used when there is no commercially available dosage form for adjustable dosing. In most cases, there is a lack of stability data to allow for an accurately assigned shelf life and storage conditions to give greater confidence of product safety and efficacy over its shelf life. The aim of this study was to evaluate the physical, chemical and microbiological stability of an extemporaneous oral liquid suspension of losartan potassium, 5 mg/mL, used to treat paediatric hypertension in Our Lady’s Children’s Hospital Crumlin, Ireland. The losartan content of extemporaneous oral suspensions, prepared with and without addition of water, was measured by UV and confirmed by HPLC analysis. Suspensions were stored at 4 °C and room temperature (RT) and were monitored for changes in; pH, colour, odour, re-dispersibility, Total Aerobic Microbial Count, Total Yeast and Mould Count and absence of E. coli. Results showed that suspensions prepared by both methods, stored at 4 °C and RT, were physically and microbiologically stable over 28 days. Initial losartan content of all suspensions was lower than expected at 80–81% and did not change significantly over the 28 days. HPLC and NMR did not detect degradation of losartan in the samples. Suspensions prepared in water showed 100% losartan content. The reduced initial losartan content was confirmed by HPLC and was related to the acidic pH of the suspension vehicle. Physiochemical properties of the drug are important factors for consideration in the selection of suspension vehicle for extemporaneous compounding of oral suspensions as they can influence the quality, homogeneity and efficacy of these preparations.

scholarly journals Motor Adaptation to Cognitive Challenges and Destabilizing Treadmill Walking in Healthy Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 523-523
Author(s):  
Pei-Chun Kao ◽  
Michaela Pierro
Keyword(s):  
Older Adults ◽  
Cognitive Task ◽  
Daily Lives ◽  
Healthy Older Adults ◽  
Trunk Motion ◽  
Visual Color ◽  
Stability Data ◽  
Serial Addition ◽  
Task Conditions ◽  
Perturbed Walking

Abstract To develop effective fall prevention intervention, it is necessary to understand how older adults respond to challenges that demand cognitive-motor dual-tasking capability, an important capability in the daily lives. The purpose of this study is to investigate how older adults adjust their motor responses when encountering cognitive and walking perturbations simultaneously. We recorded kinematic data as subjects walked on a treadmill with or without 1) continuous random-amplitude treadmill platform sways (Perturbed vs. No-perturbed walking); and 2) each of the four cognitive tasks: Paced Auditory Serial Addition test (PASAT), clock test, visual color-word incongruent test (V-stroop), and auditory pitch-word incongruent test (A-stroop). We computed dynamic margins of stability (MOS), gait variability, and short-term local divergence exponent (LDE) of the trunk motion (local stability). Data of ten older subjects (age: 72.2±4.9) show that cognitive performance did not differ between standing, Perturbed or No-perturbed walking. Subjects demonstrated significantly greater local instability and variability in step measures, joint angle and MOS during Perturbed than No-perturbed walking (p<0.001). During dual-task conditions, subjects walked with significantly larger medio-lateral MOS (MOSML) compared to walking only, especially during early phase of the trial. During Perturbed walking, subjects had significantly larger MOSML during PASAT and Vstroop than walking only. Our data showed that subjects tried to increase their dynamic MOS during Perturbed walking or a cognitive task more difficult or taxing visual attention. However, the adjustments do not sustain throughout the trial. These findings suggest older adults tend to prioritize cognitive over walking tasks even when encountering walking perturbations.

scholarly journals The accuracy of gypsum casts obtained from the disinfected extended-pour alginate impressions through prolonged storage times

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rania A. Sharif ◽  
Khalid M. Abdelaziz ◽  
Najla M. Alshahrani ◽  
Fatimah S. Almutairi ◽  
Mohrah A. Alaseri ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Storage Time ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Superior Surface ◽  
Stability Data ◽  
Surface Detail ◽  
Storage Times ◽  
One Way Anova ◽  
Chemical Disinfection

Abstract Background Manufacturers of the extended-pour alginates claimed their dimensional stability through prolonged storage. No data confirmed the ability of these materials to maintain their dimensions and the reproduced oral details following their chemical disinfection. Therefore, this study evaluated the dimensional stability and surface detail reproduction of gypsum casts obtained from disinfected extended-pour alginate impressions through different storage time intervals. Methods Two hundred and forty three hydrocolloid impressions were made from one conventional (Tropicalgin) and two extended-pour (Hydrogum 5 and Chromaprint premium) alginates. These impressions were subjected to none, spray and immersion disinfection before their storage in 100% humidity for 0, 72 and 120 h. The dimensional stability and the surface detail reproduction were indirectly evaluated under low angle illumination on the resulted gypsum casts. At α = 0.05, the parametric dimensional stability data were analyzed using One-Way ANOVA and Tukey’s comparisons, while the nonparametric detail reproduction data were analyzed using KrusKal Wallis and Mann–Whitney's tests. Results All gypsum casts exhibited a degree of expansion; however, the recorded expansion values did not differ between test categories (P > 0.05). Generally, casts obtained from spray-disinfected impressions showed lower detail accuracy (P < 0.05). Immersion-disinfected extended-pour alginates produced casts with better detail accuracy following 120 h of storage (P < 0.05). Conclusion All alginates materials offer comparable cast dimensions under different testing circumstances. Extended-pour alginates offer casts with superior surface details following their immersion disinfection and 120 h of storage. Spray-disinfection using 5.25% sodium hypochlorite affects the surface details of casts obtained from conventional and extended-pour alginates adversely.

Parenteral Histamine2-Receptor Antagonists in the Pediatric Population

1994 ◽  
Vol 10 (2) ◽  
pp. 53-57
Author(s):  
Neeta Bahal O'Mara ◽  
Milap C. Nahata
Keyword(s):  
Product Information ◽  
Pediatric Population ◽  
Data Extraction ◽  
Infants And Children ◽  
Optimal Dosage ◽  
Receptor Antagonists ◽  
Study Selection ◽  
Stability Data ◽  
Administration Methods ◽  
In Infants And Children

Objective: To provide a review of the use of parenteral histamine2 (H2)-receptor antagonists cimetidine, ranitidine, and famotidine in the pediatric population. Data Sources: Information was identified by MEDLINE and a review of journals. References cited in published articles and manufacturers' product information also were used. Study Selection: Information was selected for review if it addressed the parenteral administration of H2-receptor antagonists in the pediatric population. Data Extraction: Data were extracted from references pertaining to the topic. Data Synthesis: Despite the lack of Food and Drug Administration pediatric labeling, the H2-receptor antagonists often are used for a variety of indications in infants and children. Although these agents differ somewhat in chemical structure, potency, and pharmacokinetics, the most important differences exist in their drug interactions and adverse effect profiles. Further, administration methods, compatibility, and stability data differ slightly among the agents. Conclusions: Parenteral H2-receptor antagonists are used for a variety of indications in infants and children. Despite their widespread use, additional studies are needed to define the optimal dosage regimens in this population.

Surface and Colloid Chemistry of Systems Containing Pure Sugar Surfactant

Langmuir ◽  
1998 ◽  
Vol 14 (17) ◽  
pp. 4699-4709 ◽  
Author(s):  
R. Aveyard ◽  
B. P. Binks ◽  
J. Chen ◽  
J. Esquena ◽  
P. D. I. Fletcher ◽  
...  
Keyword(s):  
Colloid Chemistry

The role of colloid chemistry in modeling deep bed liquid filtration

1975 ◽  
Vol 30 (9) ◽  
pp. 1035-1047 ◽  
Author(s):  
W.J. Wnek ◽  
D. Gidaspow ◽  
D.T. Wasan
Keyword(s):  
Colloid Chemistry ◽  
Liquid Filtration
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