Subphase pH effect on the limiting molecular area of amphiphilic β-diketones in Langmuir monolayers

Nanostructured films of lignin (macromolecule extracted from sugar cane bagasse), polypyrrole (conducting polymer) and bis butylimido perylene (organic dye) were used in the detection of trace levels of fluorine (from H2SiF6), chlorine (from NaClO), Pb+2, Cu+2, and Cd+2 in aqueous solutions. Langmuir monolayers on ultrapure water were characterised by surface pressure-mean molecular area (Π-A) isotherms. Langmuir-Blodgett (LB) films were transferred onto gold interdigitated electrodes and used as individual sensing units of an electronic tongue system. Impedance spectroscopy measurements were taken with the sensor immersed into aqueous solutions containing the ions described above in different molar concentrations. Fourier transform infrared absorption (FTIR) was employed to identify possible interactions between the LB films and the analytes in solution, and no significant changes could be observed in the FTIR spectra of BuPTCD and Ppy. Therefore, the results for lignin point to an interaction involving the electronic cloud of the phenyl groups with the metallic ions.

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Nanostructured Films Employed as Sensing Units in an "Electronic Tongue" System

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.18043 ◽

2007 ◽

Vol 7 (2) ◽

pp. 510-514 ◽

Cited By ~ 1

Author(s):

B. A. da Silva ◽

P. A. Antunes ◽

D. Pasquini ◽

A. A. S. Curvelo ◽

R. F. Aroca ◽

...

Keyword(s):

Aqueous Solutions ◽

Electronic Tongue ◽

Langmuir Monolayers ◽

Metallic Ions ◽

Ultrapure Water ◽

Molecular Area ◽

Nanostructured Films ◽

Lb Films ◽

Langmuir Blodgett ◽

Lignin Macromolecule

Nanostructured films of lignin (macromolecule extracted from sugar cane bagasse), polypyrrole (conducting polymer) and bis butylimido perylene (organic dye) were used in the detection of trace levels of fluorine (from H2SiF6), chlorine (from NaClO), Pb+2, Cu+2, and Cd+2 in aqueous solutions. Langmuir monolayers on ultrapure water were characterised by surface pressure-mean molecular area (Π-A) isotherms. Langmuir-Blodgett (LB) films were transferred onto gold interdigitated electrodes and used as individual sensing units of an electronic tongue system. Impedance spectroscopy measurements were taken with the sensor immersed into aqueous solutions containing the ions described above in different molar concentrations. Fourier transform infrared absorption (FTIR) was employed to identify possible interactions between the LB films and the analytes in solution, and no significant changes could be observed in the FTIR spectra of BuPTCD and Ppy. Therefore, the results for lignin point to an interaction involving the electronic cloud of the phenyl groups with the metallic ions.

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Direct measurement of local field factors for second-harmonic generation from quantum dot Langmuir monolayers compressed through the metal-insulator transition

Philosophical Magazine B ◽

10.1080/014186399256637 ◽

1999 ◽

Vol 79 (9) ◽

pp. 1299-1305

Author(s):

C. P. Collier, S. Henrichs, J. R. Heat

Keyword(s):

Quantum Dot ◽

Second Harmonic Generation ◽

Direct Measurement ◽

Harmonic Generation ◽

Local Field ◽

Second Harmonic ◽

Langmuir Monolayers ◽

Insulator Transition ◽

Metal Insulator Transition ◽

Metal Insulator

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pH EFFECT ON THE BIOSORPION OF Cu2+ FROM AQUEOUS SOLUTION BY SACCHAROMYCES CEREVISIAE

Environmental Engineering and Management Journal ◽

10.30638/eemj.2003.023 ◽

2003 ◽

Vol 2 (3) ◽

pp. 243-254

Author(s):

Loredana Brinza ◽

Maria Gavrilescu

Keyword(s):

Saccharomyces Cerevisiae ◽

Aqueous Solution ◽

Ph Effect

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Amorphous Solid Dispersion Tablets Overcome Acalabrutinib pH Effect in Dogs

Pharmaceutics ◽

10.3390/pharmaceutics13040557 ◽

2021 ◽

Vol 13 (4) ◽

pp. 557

Author(s):

Deanna M. Mudie ◽

Aaron M. Stewart ◽

Jesus A. Rosales ◽

Nishant Biswas ◽

Molly S. Adam ◽

...

Keyword(s):

Solid Dispersion ◽

Drug Exposure ◽

Ph Effect ◽

Hydroxypropyl Methylcellulose ◽

Amorphous Solid ◽

Gastric Ph ◽

Patient Treatment ◽

Oral Exposure ◽

Amorphous Solid Dispersion ◽

Plasma Drug

Calquence® (crystalline acalabrutinib), a commercially marketed tyrosine kinase inhibitor (TKI), exhibits significantly reduced oral exposure when taken with acid-reducing agents (ARAs) due to the low solubility of the weakly basic drug at elevated gastric pH. These drug–drug interactions (DDIs) negatively impact patient treatment and quality of life due to the strict dosing regimens required. In this study, reduced plasma drug exposure at high gastric pH was overcome using a spray-dried amorphous solid dispersion (ASD) comprising 50% acalabrutinib and 50% hydroxypropyl methylcellulose acetate succinate (HPMCAS, H grade) formulated as an immediate-release (IR) tablet. ASD tablets achieved similar area under the plasma drug concentration–time curve (AUC) at low and high gastric pH and outperformed Calquence capsules 2.4-fold at high gastric pH in beagle dogs. In vitro multicompartment dissolution testing conducted a priori to the in vivo study successfully predicted the improved formulation performance. In addition, ASD tablets were 60% smaller than Calquence capsules and demonstrated good laboratory-scale manufacturability, physical stability, and chemical stability. ASD dosage forms are attractive for improving patient compliance and the efficacy of acalabrutinib and other weakly basic drugs that have pH-dependent absorption.

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