A Validated RP-HPLC Stability Method for the Estimation of Chlorthalidone and Its Process-Related Impurities in an API and Tablet Formulation

Table 7

Robustness values for the chlorthalidone and the in-house process-related impurities.

Sr. no.	Name	Control	pH		Flow rate		Wavelength
		RRT
			pH 5.3	pH 5.7	1.2 mL/min	1.6 mL/min	218 nm	222 nm
1	Chlorthalidone	1.0	1.0	1.0	1.0	1.0	1.0	1.0
2	Stage II process impurity	4.91	4.98	4.89	4.90	4.93	4.92	4.91
3	Stage III process impurity	1.45	1.49	1.42	1.45	1.44	1.46	1.45