Spectrophotometric determination of gabapentin in pharmaceutical formulations using ninhydrin and pi-acceptors

Simple, rapid and sensitive spectrophotometric procedures are developed for the analysis of gabapentin in pure form as well as in their pharmaceutical formulations. The methods are based on the reaction of gabapentin as n-electron donor with ninhydrin and pi-acceptors namely, 2,3,5,6-tetrachloro-1,4-benzoquinone, chloranilic acid, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, tetracyanoethylene and 7,7,8,8-tetracyanoquinodimethane. The obtained complexes were measured at 568, 230, 314, 304, 335 and 439 nm for ninhydrin, chloranil, Chloranilic acid, DDQ, TCNE and TCNQ respectively. The proposed procedures could be successfully applied to the determination of gabepentin with good recovery; percent ranged from 99.3 to 100.7 The association constants and free energy changes using Benesi-Hildebrand plots are also studied.