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This is a draft proposal for The International Pharmacopoeia (Working document QAS/14.589, June 2014).
The working document with line numbers and tracked changes is available for comment at www.who.int/medicines/areas/qualitv safetv/qualitv assurance/projects/ en/. Please address any comments to: World Health Organization, Quality Assurance and Safety: Medicines, Dr Herbert Schmidt, 1211 Geneva 27, Switzerland; fax: +41 22 791 4730; email: [email protected].
[Note from the Secretariat. It is proposed to revise the monograph on Pyrantel embónate.]
[Note from the editor. In accordance with WHO editorial policy the text reproduced below does not include tracked changes. Changes from the current monograph are indicated by insert and delete in the working document available at the above-mentioned web address.]
Molecular formula. C11H14N2S,C23H1606
Relative molecular mass. 594.7
Graphic formula.
Chemical name. (E)-1,4,5,6-Tetrahydro-1-methyl-2-[2-(2-thienyl)vinyl]pyrimidine compound with 4,4'-methylenebis[3-hydroxy-2-naphthoate] (1:1); (E)-1,4,5,6-tetrahydro-1-methyl-2-[2-(2thienyl)ethenyl]pyrimidine 4,4'-methylene-bis[3-hydroxy-2-naphthalenecarboxylate] (1:1); CAS Reg. No. 22204-24-6.
Other name. Pyrantel pamoate.
Description. A pale yellow or yellow powder.
Solubility. Practically insoluble in water and methanol R; soluble in dimethyl sulfoxide R; slightly soluble in dimethylformamide R.
Category. Anthelmintic.
Storage. Pyrantel embónate should be kept in a well-closed container, protected from light.
Requirements
Definition. Pyrantel embónate contains not less than 98.0 and not more than 102.0 of CnH14N2S,C23H1606, calculated with reference to the dried substance.
Identity tests
* Either tests A alone or tests B and C may be applied.
A. Carry out the examination as described under 1.7 Spectrophotometry in the infrared region. The infrared absorption spectrum is concordant with the spectrum obtained from pyrantel embónate RS or with the reference spectrum of pyrantel embónate.
B. The absorption spectrum of a 13 pg/mL solution in methanol R, when observed between 230 nm and 360 nm, exhibits 2 maxima at about 288 nm and 300 nm. The ratio of the absorbance at 288 nm to that at 300 nm is about 1.0.
C. See the test described under "Related substances", Method A. The principal spots obtained with solution (1 ) correspond in position, appearance and intensity with those obtained with solution (3).
Chlorides. Dissolve 0.46 g of Pyrantel embónate in a mixture of 10 mL of nitric acid (-130 g/L)...