Solvent Effects on Extraction of Sodium Picrate with 15-Crown-5. The Determination of Ion-Pair Formation Constant of Crown Ether–Metal Salt 1 : 1 : 1 Complex in Water

1994 ◽  
Vol 67 (1) ◽  
pp. 56-60 ◽  
Author(s):  
Yasuyuki Takeda ◽  
Chihiro Takagi
Keyword(s):  
Crown Ether ◽  
Solvent Effects ◽  
Formation Constant ◽  
Metal Salt ◽  
Ion Pair ◽  
Pair Formation ◽  
Sodium Picrate ◽  
Ion Pair Formation

Rapid Colorimetric Assay of Trimethoprim and Sulfamethoxazole in Pharmaceuticals

1983 ◽  
Vol 66 (6) ◽  
pp. 1447-1449 ◽  
Author(s):  
Asis K Sanyal ◽  
Dinabandhu Laha
Keyword(s):  
Solvent Extraction ◽  
Colorimetric Assay ◽  
Pharmaceutical Preparations ◽  
Ion Pair ◽  
Pair Formation ◽  
Bromophenol Blue ◽  
Colorimetric Determination ◽  
Ion Pair Formation ◽  
Subsequent Measurement

Abstract A method is described for the direct colorimetric determination of trimethoprim and sulfamethoxazole in pharmaceutical preparations, without prior separation. Estimation of trimethoprim is based on its ion-pair formation with bromophenol blue and subsequent measurement of absorbance of the ionpair at 418 nm. Estimation of sulfamethoxazole is possible without removal of trimethoprim by solvent extraction.

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