Author(s)

Abraham Salois¹, Iris Perez², Ervin Palma³, Ethan Goolish⁴, Yuri Griko^5*

¹Chief Dull Knife College, Lame Deer, USA.
²Evergreen Valley College, San Jose, USA.
³California State University Eastbay, Hayward, USA.
⁴Mountain View High School, Mountain View, USA.
⁵National Aeronautics and Space Administration, Ames Research Center, Moffett Field, USA.

One of the major problems associated with the therapeutic application of β-lactam antibiotics is their significant instability [1]-[3]. Analogs from that group are easily degraded in aqueous solutions and in solid state, which happens predominantly as a result of β-lactam ring chemical degradation. Because of this, the chemical integrity of β-lactam antibiotics must be closely monitored to meet FDA requirements. The original iodometric method based on visual detection of the end products of beta-lactamase hydrolysis that has been used to test beta-lactamase activity [4] was modified to quantitatively assess the amount of degraded product in amoxicillin. A UV-visible spectrophotometric method has been used, focusing on the ability of the products from the degradation of β-lactam analogs to absorb iodine from bulk solution, resulting in a significant reduction in the absorption spectra. Amoxicillin trihydrate tablets with different expiration dates and amoxicillin samples pre-loaded with known amounts of degraded amoxicillin have been used to generate a calibration curve and quantify the presence of degraded materials. Results show that the changes in the absorption spectra of iodine reagent directly correlate with the fraction of degraded β-lactam antibiotics, such as amoxicillin, in commercial products. The proposed assay might be as close as one step from simpler and cheaper methods of quantitative analysis of degraded β-lactam analogs, with estimated sensitivity in the range of 1% - 2%, which is better than the current FDA requirements.

Amoxicillin, Iodine, Chemical Integrity

Salois, A. , Perez, I. , Palma, E. , Goolish, E. and Griko, Y. (2015) Evaluation of the Chemical Integrity of Beta-Lactam Antibiotics by Iodine-Based Assay. Journal of Biosciences and Medicines, 3, 91-99. doi: 10.4236/jbm.2015.311012.