An eco-friendly and alternative method of forced degradation of fluoroquinolone drugs by microwave irradiation: a new application for analytical eco-scale

Abstract

Forced degradation studies are essential to determine the drug stability, elucidate the main degradation routes, and monitor the degradation products in qualitative/quantitative terms. Over the years, the pharmaceutical industry has been using a traditional and conventional method that employs a stove as the heating source; this requires a lengthy process and high energy. Recently, a new forced degradation method using modern microwave reactors has been reported as a greener, more economical and efficient alternative. The present work reports for the first time degradation of fluoroquinolone drugs (levofloxacin and norfloxacin) under microwave irradiation. Also for the first time, it presents the utilization of analytical eco-scale as a novel comprehensive approach to evaluating the greenness of analytical methodology for studies on the forced degradation. The objective of this study was to design and validate a forced degradation method assisted by microwave irradiation, alongside a conventional stress degradation study, and to compare the two methods. Microwave irradiation showed excellent performance as it yielded similar amounts of specific degradation products for both drugs, equivalent to what is produced in the conventional procedure. Therefore, there were some advantages to the new eco-friendly degradation method with respect to the significantly reduced time (72 times), energy (360 times), reagents and waste.