Development and Validation of Stability-Indicating RP-UPLC Method for Simultaneous Determination of Related Substances of S(−)Amlodipine and S(−)Metoprolol Succinate in Fixed Dose Combination Tablet Dosage Form

Table 11

Results of robustness.

Parameters	Values	Tailing factor		USP plates		%RSD of STD		%RSD of AL Imp.-A	%RSD of MT Imp.	%RSD of Unknown Imp.	%RSD of total Imp.
Control	As per method	AL	MT	AL	MT	AL	MT
Column; (different serial number)	Precision	1.28	1.49	193410	28616	0.25	0.12	0.22	0.19	2.0	0.26
	Intermediate precision	1.23	1.20	97580	18686	0.41	0.09	0.23	0.57	1.96	1.55
Flow; (−0.1 and +0.05 mL/min)	0.4 mL/min	1.23	1.37	179599	31125	0.36	0.18	2.24	1.29	4.17	2.58
	0.55 mL/min	1.15	1.31	148500	24413	0.35	0.13	2.55	0.55	10.64	0.89
Wavelength (±2 nm)	230 nm	1.06	1.06	65255	8954	1.40	1.18	2.55	2.25	4.08	0.57
	234 nm	1.10	1.10	70523	9120	1.23	0.74	0.87	3.80	4.00	1.96
Oven temperature; (−5 and +2°C)	40°C	1.17	1.31	152064	25101	0.21	0.20	3.08	0.37	13.21	2.40
	47°C	1.20	1.44	279462	44894	0.80	0.19	2.29	1.31	3.92	0.45