Spectrophotometric determination of some pharmaceutical amides through charge-transfer complexation reactions.
A spectrophotometric method is described for the assay of fenpipramide hydrochloride, isopropamide iodide, trimethobenzamide hydrochloride, morphazinamide hydrochloride and tolazamide. The method is based on the formation of a charge-transfer complex between the drug as n-donor and iodine, a sigma-acceptor. The product exhibits absorption maxima at 295 and 365 nm; measurements are made at 365 nm for fenpipramide and at 295 nm for the other compounds. Beer's law is obeyed in a concentration range of 1-120 micrograms ml-1. The method is rapid, simple and sensitive and can be applied to the analysis of some commercial and laboratory prepared tablets without interference. A more detailed investigation of the complex was made with respect to its composition, association constant and free energy change.
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Assiut University, Egypt.
G A
GA
Saleh
H F
HF
Askal
D000577:Amides / Q000032:analysis* / Q000737:chemistry; D001549:Benzamides / Q000032:analysis; D004158:Diphenylacetic Acids / Q000032:analysis; D007202:Indicators and Reagents; D011719:Pyrazines / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013607:Tablets; D014042:Tolazamide / Q000032:analysis
D000577:Amides; D001549:Benzamides; D004158:Diphenylacetic Acids; D007202:Indicators and Reagents; D011719:Pyrazines; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D013607:Tablets; C003148:fenpipramide; C038993:morphazinamide; D014042:Tolazamide; C100146:trimethobenzamide