Solution Chemistry in Fused Phenol. III. Conductance Studies of the Solutions of Acids, Bases and Salts in Fused Phenol

1979 ◽  
Vol 32 (5) ◽  
pp. 1039 ◽  
Author(s):  
KC Malhotra ◽  
VP Mahajan ◽  
RG Sud
Keyword(s):  
Quaternary Ammonium ◽  
Lewis Acids ◽  
Ion Pair ◽  
Pair Formation ◽  
Solution Chemistry ◽  
Inorganic Salts ◽  
Weak Bases ◽  
Triple Ion Formation ◽  
Triple Ion ◽  
Protonic Acids

Conductance measurements of protonic acids, Lewis acids, bases and quaternary ammonium and inorganic salts have been carried out in fused phenol at 50 � 0.1°C. The possibility of triple ion formation has been ruled out: however, an extensive ion pair formation in the solution is supported by results from plots of Λc against log√C Λ0 values have been determined for these solutes. A possibility of the estimation of weak bases, in fused phenol, has been explored, fluorosulfuric acid being used as a titrant.

Solution chemistry in dichloroacetic acid. II. Conductance studies of acids and bases in dichloroacetic acid

1976 ◽  
Vol 29 (9) ◽  
pp. 1931
Author(s):  
KC Malhotra ◽  
RG Sud
Keyword(s):  
Lewis Acids ◽  
Ion Pair ◽  
Pair Formation ◽  
Solution Chemistry ◽  
Dichloroacetic Acid ◽  
Acids And Bases ◽  
Triple Ion Formation ◽  
Triple Ion ◽  
Protonic Acids

Conductance measurements of protonic acids and Lewis acids have been carried out in dichloroacetic acid at 25 � 0.l�C. Λ0, values have been determined for these acids; it is found that there is extensive ion-pair formation in solution. The role of CHCl2CO2H as a differentiating solvent has been explored. Triple-ion formation for SbCl5 and AlBr3 is indicated which is supported by log C against logΛc curves. Similar trends have been indicated for organic tertiary bases in dichloroaceticacid. Conductometric studies of the same salts in dichloroacetic acid have also been carried out. Fluorosulphuric acid has been developed as an acidic titrant for the estimation of bases in dichloroacetic acid.

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.

Ion-Pair and Triple-Ion Formation by Some Tetraalkylammonium Iodides in Binary Mixtures of 1,4-Dioxane + Tetrahydrofuran

2008 ◽  
Vol 53 (7) ◽  
pp. 1417-1420 ◽  
Author(s):  
Mahendra Nath Roy ◽  
Prasanna Pradhan ◽  
Rajesh Kumar Das ◽  
Biswajit Sinha ◽  
Prabir Kumar Guha
Keyword(s):  
Binary Mixtures ◽  
Ion Pair ◽  
Ion Formation ◽  
Triple Ion Formation ◽  
Triple Ion
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