Green gas chromatographic stability-indicating method for the determination of Lacosamide in tablets. Application to in-vivo human urine profiling

A direct, eco-friendly, stability-indicating GC method was developed for the determination of Lacosamide (LCM) in tablet dosage forms in presence of its degradation products as well as in human urine in presence of the co-administered drug Zonisamide (ZON). The assay method in tablets was validated according to the ICH guidelines, while the method for determination of LCM in urine was validated according to FDA; Bioanalytical Method Validation guidance. Linear response (r = 0.9998) was observed over the range of 20-280 μg/mL of LCM, with detection and quantitation limits of 5.871 and 19.57 μg/mL, respectively for the tablet assay method. While (r = 0.9999) was observed over the range of 0.5-20 μg/mL of LCM, with detection and quantitation limits of 67 and 233 ng mL−1, respectively for the urine analysis method. Under various stress conditions, the investigation of LCM forced degradation behaviour was carried out. Furthermore, monitoring of the drug in urine followed by construction of its urine profile was done after the administration of 50 mg tablet of LCM to three healthy volunteers so as to prove the ability of the method to be applied in assaying LCM in human urine. The method showed also successful separation of LCM and the co-administered drug ZON in urine. Finally, the greenness of the method was assessed using National Environmental Methods Index label and Eco scale methods.