SPECTROPHOTOMETRIC DETERMINATION OF FLUNARIZINE DIHYDROCHLORIDE THROUGH THE FORMATION OF CHARGE-TRANSFER COMPLEX WITH IODINE

A spectrophotometric method is described for the assay of flunarizine dihydrochloride. The method is based on the molecular interaction betw een the drug and iodine, to form a charge-transfer complex in which th e drug acts as n-donor and iodine as alpha-acceptor. The iodine was fo und to form charge-transfer complex in a 1:1 stoichiometry with absorp tion bands at 295 and 355 nm. The concentrations were linear over 8-13 mu g ml(-1) at both 295 and 355 nm, respectively. A complete, detaile d investigation of the formed complex was made with respect to its com position, associated constant and free energy change. The method has b een applied successfully to the analysis of commercially available flu narizine dihydrochloride capsules without interference from the capsul es excipient. To Validate the proposed method, its accuracy and precis ion, the results were statistically compared with a newly developed re versed-phase HPLC procedure using Student-t and F-ratio tests.