A PMR study of the structural changes in a quaternary ammonium base cation caused by ion-pair formation

1985 ◽  
Vol 26 (1) ◽  
pp. 30-33
Author(s):  
N. I. Grebenshchikov ◽  
S. O. Popov ◽  
V. V. Bagreev ◽  
L. A. Fedorov
Keyword(s):  
Quaternary Ammonium ◽  
Structural Changes ◽  
Base Cation ◽  
Ion Pair ◽  
Pair Formation ◽  
Quaternary Ammonium Base ◽  
Ion Pair Formation

Ion-Pair Formation of Quaternary Ammonium Salts in Hydrogen-Bonded Solvents

1972 ◽  
Vol 81 (1-4) ◽  
pp. 148-157 ◽  
Author(s):  
F. Accascina ◽  
M. Goffredi ◽  
R. Triolo
Keyword(s):  
Quaternary Ammonium ◽  
Ion Pair ◽  
Pair Formation ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Ion Pair Formation ◽  
Hydrogen Bonded

scholarly journals Evaluation of Ion-pair Formation of Adefovir to Improve Permeation across Artificial and Biological Membranes

2018 ◽  
Vol 21 ◽  
pp. 160-170 ◽  
Author(s):  
Bahar Darsazan ◽  
Alireza Shafaati ◽  
Afshin Zarghi ◽  
Seyed Alireza Mortazavi
Keyword(s):  
Quaternary Ammonium ◽  
Adefovir Dipivoxil ◽  
Ion Pair ◽  
Pair Formation ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Apparent Permeability ◽  
Ion Pair Formation ◽  
Counter Ion ◽  
Everted Gut Sac

Purpose: Adefovir is an antiviral drug that exhibits high hydrophilic properties and negligible bioavailability (less than 12%). It is only applied in the form of the ester prodrug adefovir dipivoxil (ADV). The oral bioavailability of ADV is limited (32% to 45%) by its low permeability (Class 3) and biological conversion of the prodrug to adefovir. Ion-pair formation is considered as an alternative approach to a covalent prodrug (ADV) to enhance intestinal permeation of adefovir. Methods: The effect of various counter-ions (anionic, cationic and two quaternary ammonium salts) on the lipophilicity of adefovir was investigated by means of the n-octanol/buffer partitioning system, an in vitro transport model (PAMPA) and a biological membrane (everted gut sac). Results: Quaternary ammonium salts, cetylpyridinium chloride (CPC) and cetrimide enhanced the lipophilicity of adefovir 136- and 87-fold, respectively. The apparent permeability of adefovir in combination with CPC (counter-ion) was 2.5-fold greater than ADV permeability in the PAMPA model. The apparent permeability of adefovir-CPC (counter-ion) was 1.3-fold greater than that of adefovir dipivoxil permeability in a biologic membrane (everted gut sac). Conclusion: These results suggest that the adefovir-CPC ion-paired system has potential for improving the permeation of adefovir across the intestinal membrane. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

scholarly journals The Ion Pair Formation of Quaternary Ammonium Picrates in Aqueous Methylene Chloride at 25 degrees C Studied by Conductivity and Distribution.

1976 ◽  
Vol 30a ◽  
pp. 687-691 ◽  
Author(s):  
Per Beronius ◽  
Arne Brändström ◽  
Kjartan Marøy ◽  
Marja-Liisa Pohjonen ◽  
Jouko Koskikallio
Keyword(s):  
Quaternary Ammonium ◽  
Methylene Chloride ◽  
Ion Pair ◽  
Pair Formation ◽  
Ion Pair Formation

Extraction of organic acids by ion-pair formation with tri-n-octylamine

1985 ◽  
Vol 178 ◽  
pp. 189-195 ◽  
Author(s):  
M. Puttemans ◽  
L. Dryon ◽  
D.L. Massart
Keyword(s):  
Organic Acids ◽  
Ion Pair ◽  
Pair Formation ◽  
Ion Pair Formation

scholarly journals Determination of ABT-861 by High-Performance Liquid Chromatography and a Model for Ion-Pair Formation with Trifluoroacetic Acid

1999 ◽  
Vol 37 (6) ◽  
pp. 185-190
Author(s):  
N. Simonzadeh ◽  
B. Levison ◽  
A. Buko ◽  
K. Matuszak ◽  
M. Hanscom
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Trifluoroacetic Acid ◽  
High Performance ◽  
Ion Pair ◽  
Pair Formation ◽  
Ion Pair Formation

Charge-transfer stabilization of molecular bicimers: ion pair formation in diarylmethanes

1988 ◽  
Vol 92 (7) ◽  
pp. 1703-1705 ◽  
Author(s):  
R. J. Locke ◽  
Steve H. Modiano ◽  
E. C. Lim
Keyword(s):  
Charge Transfer ◽  
Ion Pair ◽  
Pair Formation ◽  
Ion Pair Formation
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