Spectrophotometric Method for Determination of Five 1,4-Dihydropyridine Drugs Using N-Bromosuccinimide and Indigo Carmine Dye

Table 3

Robustness studies for NBS/INC method.

Variation	Recovery% ± SD^a
	NIF^b	NIC^b	NIM^b	FEL^b	AML^b
No variation	99.41±0.65	97.22±1.07	99.80±0.33	99.71±1.16	99.80±0.23
NBS conc.
0.019% w/v	99.32±0.36	97.82±0.38	97.82±0.79	99.62±0.54	97.44±0.34
0.021% w/v	97.25±0.63	99.38±0.53	99.55±0.74	98.55±0.63	99.26±0.22
INC conc.
0.069% w/v	97.90±1.75	99.30±0.67	99.67±0.78	97.71±0.89	98.71±1.33
0.071% w/v	98.15±0.95	97.18±0.15	99.82±0.39	98.27±0.29	99.10±0.28
Reaction time of NBS
With INC
9 min	98.16±0.69	99.15±0.16	97.41±0.38	98.77±0.19	99.92±0.19
11 min	99.20±1.05	98.44±0.67	98.56±0.86	97.21±0.98	100.22±1.05
With drug
24 min	99.73±0.72	99.70±1.38	98.28±1.02	100.26±1.15	97.78±0.15
26 min	98.12±0.98	97.51±1.15	99.21±0.73	99.71±0.65	98.74±1.65

aMean of three determinations.
^bDrugs concentration 10.0 μg/mL.