SPECTROPHOTOMETRIC STUDY OF THE CHARGE-TRANSFER COMPLEXES OF SOME PHARMACEUTICAL BUTYROPHENONES

The molecular interactions between haloperidol and droperidol as elect ron donors and each of iodine; 7,7,8,8-tetracyanoquinodimethane (TCNQ) ; 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ); tetracyanoethylene (TCNE); 2,4,7-trinitro-9-fluorenon (TNF); and 2-3-5-6-tetrabromo-1,4-b enzoquinone (Bromanil) as accepters have been investigated spectrophot ometrically. Different variables affecting the reaction were studies a nd optimized. Beer's law was obeyed in a concentration limit of 2.5-25 00 mu g ml(-1) for the studied drugs with various accepters used. Elec tron affinities (E-A) of the accepters were found to correlate with bo th the time required for maximum colour formation and the molar absorp tivities of haloperidol and droperidol. A Job's plot of the absorbance versus the molar ratio of the drugs to iodine indicated 1:1 ratio. Th e proposed methods were found to be rapid and sensitive and may be app lied for estimation of named drugs in pharmaceutical dosage forms with out interferences from the common additives encountered. Percentage re coveries ranged from 99.1-102.2%. (C) 1997 Elsevier Science B.V.