Investigation of Acid-Base Indicator Property of Plumbagin from Plumbago zeylanica Linn

Table 6

Effects of the indicator concentration on the method robustness.

HCl/NaOH (mL)			CH3COOH/NaOH (mL)			Assay of pure ibuprofen powder (% purity)			Assay of ibuprofen BP tablets (% content)
0.05%	0.10%	0.15%	0.05%	0.10%	0.15%	0.05%	0.10%	0.15%	0.05%	0.10%	0.15%
9.99	10.09	10.18	10.90	11.08	11.00	100.30	99.30	98.80	99.98	96.00	97.30
9.99	10.18	10.18	11.00	11.10	11.08	100.30	99.80	99.30	97.10	97.82	96.78
9.99	9.99	10.18	10.90	11.00	11.08	99.80	99.80	98.80	98.67	96.87	95.53
10.09	9.99	10.27	10.90	10.90	11.08	100.30	100.30	99.80	97.50	96.80	97.10
9.99	10.09	10.09	11.00	11.00	11.00	99.80	100.30	99.30	99.50	97.67	96.82
10.09	9.99	10.09	11.08	11.31	10.90	99.80	100.30	99.80	98.50	96.90	97.25
Mean = 10.02 ± 0.021	Mean = 10.06 ± 0.032	Mean = 10.17 ± 0.028	Mean = 10.96 ± 0.030	Mean = 11.07 ± 0.057	Mean = 11.02 ± 0.029	Mean = 100.10 ± 0.112	Mean = 99.97 ± 0.167	Mean = 99.30 ± 0.183	Mean = 98.54 ± 0.454	Mean = 97.01 ± 0.270	Mean = 96.80 ± 0.268
RSD = 0.52%	RSD = 0.78%	RSD = 0.67%	RSD = 0.69%	RSD = 1.26%	RSD = 0.65%	RSD = 0.27%	RSD = 0.41%	RSD = 0.45%	RSD = 1.13%	RSD = 0.68%	RSD = 0.68%