Two sensitive and precise methods were developed and validated for simultaneous estimation of dalfampridine with its oxidative degradation in pharmaceutical formulations without noticeable interference. Among the techniques adopted were chromatography [coupled TLC-densitometry and HPLC]. Method I: chromatographic separation a Spheri-5 RP C8 (220 X 4.6 X 5μm particle size) column was used in addition to the mobile phase [acetonitrile and 0.05 M KH2PO4 - (pH=5), (65: 35 v /v)], with a flow rate of (1ml.min−1) by detection (UV) at 298 nm. Method II: Densitometric separation of the drugs was performed on aluminium plates precoated with silica gel 60 F254 plates, with mobile phase chloroform, acetonitrile and methanol (volume 6:3:1) and measuring densitometry at 254 nm. HPLC calibration outline were set by the zone (0.2-6 μg mL-1), and retention time (Rt) values for oxidative dalfampridine degradation and intact dalfampridine were setup (2.0+0.03, and 3.5+0.02) minutes respectively. While TLC outline were set by the zone (0.5-6 μg /spot) and retention time (Rt) values were setup to be 0.84 for entire dalfampridine and (0.26 and 0.72) for its degradation, respectively. LOD (μg. ml-1) was (0.054, 0.098) and LOQ (μg. ml-1) was (0.179, 0.325) for HPLC and TLC respectively.
The improved procedural steps were verified with prefect precision, consistency in addition to cost efficient, according to the guidelines requirement of the International Conference on Harmonization (ICH). And statistically, the results were compared and matched to the published method with no considerable interference.