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

Table 5

Results for the % recovery with the chlorthalidone API.

	% recovery
	50%			100%			150%
Stage II process impurity	99.90	100.08	100.27	99.47	99.77	99.83	97.74	98.62	99.49
Mean % recovery	100.08			99.69			98.62
SD	988.55			2102.35			14152.62
%RSD	0.183			0.195			0.886
Stage III process impurity	99.47	99.75	100.14	100.75	100.47	100.99	98.85	99.91	99.47
Mean % recovery	99.78			100.74			99.42
SD	1892.40			2816.47			8592.28
%RSD	0.3516			0.2591			0.5340