scholarly journals Behaviour of Tetrabenazine in Acid Medium: Reassessment and Impact on Formulation

Pharmaceutics ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 44
Author(s):  
Laurent Ettouati ◽  
Zoé Senta-Loys ◽  
Sandrine Bourgeois ◽  
Bernard Fenet ◽  
Marc Le Borgne ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Aqueous Solutions ◽  
Acid Medium ◽  
Stability Study ◽  
Reverse Phase ◽  
Acidic Solutions ◽  
Orodispersible Films ◽  
Acidic Conditions ◽  
Spectroscopy Studies ◽  
Cis Isomer

Thorough studies of previous analytical stress data of tetrabenazine, a dopamine depleting agent, showed a potential susceptibility to acidic conditions. Hence, the behavior of tetrabenazine acidic solutions was studied by LC-MS and NMR spectroscopy. Reverse-phase LC-MS analysis of tetrabenazine acidic aqueous solutions consistently showed a main lipophilic impurity in a proportion of 15 to 20%. NMR spectroscopy studies did not allow to completely ascertain its structure. However, we hypothesize an interconversion of trans-tetrabenazine with its unstable cis isomer via an open isoquinolinium intermediate. Evaluation of tetrabenazine integrity in orodispersible films was reassessed in light of these observations after formulation and during stability study. Even if interconversion of trans-tetrabenazine with its cis isomer was observed in orodispersible films containing tetrabenazine, this phenomenon seems not to have any consequences for the overall tetrabenazine bioavailability.

scholarly journals Modified Rhamnogalacturonan-Rich Apple Pectin-Derived Structures: The Relation between Their Structural Characteristics and Emulsifying and Emulsion-Stabilizing Properties

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1586
Author(s):  
Jessika N. Humerez-Flores ◽  
Sarah H. E. Verkempinck ◽  
Clare Kyomugasho ◽  
Paula Moldenaers ◽  
Ann M. Van Loey ◽  
...  
Keyword(s):  
Emulsion Stability ◽  
Structural Characteristics ◽  
Stability Study ◽  
Natural Food ◽  
Apple Pectin ◽  
Oil Droplets ◽  
Food Ingredients ◽  
Acidic Conditions ◽  
Hydrolysis Of ◽  
Subsequent Acid

In the context of the increasing interest in natural food ingredients, the emulsifying and emulsion-stabilizing properties of three rhamnogalacturonan-rich apple pectin-derived samples were assessed by evaluating a range of physicochemical properties. An apple pectin (AP74) was structurally modified by a β-eliminative reaction to obtain a RG-I-rich pectin sample (AP-RG). Subsequent acid hydrolysis of AP-RG led to the generation of pectin material with partially removed side chains (in particular arabinose depleted) (AP-RG-hydrolyzed), thus exhibiting differences in rhamnose, arabinose, and galactose in comparison to AP-RG. All samples exhibited surface activity to some extent, especially under acidic conditions (pH 2.5). Furthermore, the viscosity of the samples was assessed in relation to their emulsion-stabilizing properties. In a stability study, it was observed that the non-degraded AP74 sample at pH 2.5 exhibited the best performance among all the apple pectin-derived samples evaluated. This emulsion presented relatively small oil droplets upon emulsion production and was less prone to creaming than the emulsions stabilized by the (lower molecular weight) RG-I-rich materials. The AP-RG and AP-RG-hydrolyzed samples presented a slightly better emulsion stability at pH 6.0 than at pH 2.5. Yet, neither pectin sample was considered having good emulsifying and emulsion-stabilizing properties, indicated by the presence of coalesced and flocculated oil droplets.

23. A new adult rat brain slice preparation for ex vivo NMR spectroscopy studies of stroke

1994 ◽  
Vol 52 (1) ◽  
pp. A11
Author(s):  
M.T. Espanol ◽  
L. Litt ◽  
L.-H. Chang ◽  
T.L. James ◽  
P.R. Weinstein ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Rat Brain ◽  
Brain Slice ◽  
Ex Vivo ◽  
Slice Preparation ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Spectroscopy Studies ◽  
Rat Brain Slice ◽  
Brain Slice Preparation

Removal of Dyes from Aqueous Solutions by Adsorption on Chrome-Tanned Solid Wastes Generated in the Leather Industry

2003 ◽  
Vol 38 (2) ◽  
pp. 393-411 ◽  
Author(s):  
Soufiane Tahiri ◽  
Ali Messaoudi ◽  
Abderrahman Albizane ◽  
Mohamed Azzi ◽  
Mohamed Bouhria ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Operating Conditions ◽  
Solid Wastes ◽  
Cationic Dyes ◽  
Optimum Operating ◽  
Leather Industry ◽  
Anionic Dyes ◽  
Ph Values ◽  
Acidic Conditions ◽  
Dyes Adsorption

Abstract In this work, the ability of chrome shavings and of crust leather buffing dusts to remove dyes from aqueous solutions has been studied. Buffing dusts proved to be a much better adsorbent than chrome shavings for cationic dyes. The adsorption of anionic dyes is very important on two studied wastes. The pH has an obvious influence on the adsorption of dyes. Adsorption of cationic dyes is less favourable under acidic conditions (pH <3.5) and at high pH values (pH >10.5). The adsorption of anionic dyes on both adsorbents is more favourable under acidic conditions (pH <3). The adsorption on chrome shavings is improved by the use of finer particles. The kinetic adsorption was also studied. Adsorption isotherms, at the optimum operating conditions, were determined. Adsorption follows the Langmuir model. The isotherm parameters have been calculated. The column technique could be applied to treat significant volumes of solutions.

Solid-state 23Na NMR spectroscopy studies of ordered and disordered cellulose nanocrystal films

2019 ◽  
Vol 97 ◽  
pp. 31-39 ◽  
Author(s):  
Ryutaro Ohashi ◽  
Carl A. Michal ◽  
Wadood Y. Hamad ◽  
Thanh-Dinh Nguyen ◽  
Motohiro Mizuno ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Cellulose Nanocrystal ◽  
Nanocrystal Films ◽  
Spectroscopy Studies ◽  
23Na Nmr

scholarly journals DEVELOPMENT, EVALUATION, AND CHARACTERIZATION OF LOSARTAN POTASSIUM BUCCAL PATCHES USING JACKFRUIT POLYMER

2019 ◽  
pp. 24-30
Author(s):  
SOJI S ◽  
ARUN JL
Keyword(s):  
Moisture Content ◽  
In Vitro Release ◽  
Stability Study ◽  
Losartan Potassium ◽  
Content Uniformity ◽  
Zero Order Kinetics ◽  
Sink Condition ◽  
Development Evaluation ◽  
Spectroscopy Studies

Objective: The objective was to develop buccal patches of an antihypertensive drug and losartan potassium using jackfruit polymer for sustained buccal delivery. Methods: The patches were prepared by the solvent casting method. Five formulations were developed with varying concentrations of jackfruit polymer. USP type II apparatus was used to perform in-vitro release study under perfect sink condition. Buccal formulations were developed to a satisfactory level in terms of drug release, bioadhesive strength, content uniformity, moisture content, surface pH, thickness, and stability study. Results: From the results obtained F5 was found as best formulation, having appropriate folding endurance greater than 300, moisture content of 1.14±0.03 percentage (%), moisture uptake of 6.21±0.12%, swelling index (62.78%), bioadhesion strength (37.62±0.25 g), and bioadhesion time of 9 h 5 min. Fourier-transform infrared spectroscopy studies have shown no interactions between drug and polymer. All the formulations followed zero-order kinetics. Conclusion: It can be concluded that mucoadhesive buccal patches of losartan potassium using jackfruit polymer are an auspicious dosage form to prolong the release of drug and enhance its poor oral bioavailability.

Eine schnelle Methode zur quantitativen Abtrennung von Chlor und Brom aus sauren wäßrigen Lösungen / A Rapid Method for the Quantitative Elimination of Chlorine or Bromine from Aqueous Acidic Solutions

1988 ◽  
Vol 43 (1) ◽  
pp. 134
Author(s):  
Wolfram Baumgärtner ◽  
Youssef A. Gawargious ◽  
Klaus Brodersen
Keyword(s):  
Aqueous Solutions ◽  
Rapid Method ◽  
Dilute Solution ◽  
Acidic Solutions

Abstract The quantitative elimination of chlorine and bromine from acidic aqueous solutions was achieved through extraction with a dilute solution of styrene in CCl4 .

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