Abstract
The interaction of ampicillin and benzaldehyde in aqueous solution was investigated. A modified iodine colorimetry (I2-colorimetry) was used for the assay of ampicillin in solutions containing ampicillin and benzaldehyde. Thus, total ampicill n including bioactive ampicillin-like substances which are present in aqueous solution could be determined by I2-colorimetry after diluting the solution and adjusting it to pH 3.5-4.0. The time courses of degradation of ampicillin with benzaldehyde in phosphate buffer (pH 8.00) at 35°C were followed by this method, and the reaction was found to be pseudo-first-order. Further, it was found that benzaldehyde inhibited the degradation of ampicillin under these conditions. In view of the above results and the changes in the ultraviolet spectra of the solution, it is concluded that ampicillin and benzaldehyde form a complex.
