title: Determination of potassium in pharmaceutical formulations by means of 18-crown-6: extraction studies.
abstract: A colorimetric method has been developed for the determination of potassium in pharmaceutical formulations. The method is based on the formation of a complex of potassium with 18-crown-6, followed by conversion to an ion-pair with picrate anion; the ion-pair is extracted with either methylene chloride or toluene-methylene chloride (80:20, v/v) and determined colorimetrically.
authors.affiliation: Department of Pharmaceutical Sciences, University of Bologna, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Raggi
authors.forename: L
authors.initials: L
authors.lastname: Nobile
authors.forename: M
authors.initials: M
authors.lastname: Ramini
authors.forename: I
authors.initials: I
authors.lastname: Perboni
mesh_terms: D003124:Colorimetry; D043844:Crown Ethers; D004355:Drug Stability; D004988:Ethers, Cyclic; D006863:Hydrogen-Ion Concentration; D004364:Pharmaceutical Preparations / Q000032:analysis*; D010851:Picrates / Q000032:analysis; D011188:Potassium / Q000032:analysis*; D011189:Potassium Chloride / Q000032:analysis; D013053:Spectrophotometry
chemical_list: D043844:Crown Ethers; D004988:Ethers, Cyclic; D004364:Pharmaceutical Preparations; D010851:Picrates; C015762:18-crown-6; D011189:Potassium Chloride; D011188:Potassium