Stability-Indicating Assay for the Determination of Pentobarbital Sodium in Liquid Formulations

Table 1

Robustness.

Parameters	Modification	% recovery		-D	-IS	Plates
Flow rate (mL/min)	1.1	100.3	8.06	1.30	1.34	5503
	1.2	100.2	7.73	1.26	1.27	5155
	1.3	100.2	7.46	1.19	1.38	4779
Wavelength of detection (nm)	218	105.0	8.46	1.27	1.42	6042
	220	103.4	8.43	1.33	1.35	5969
	225	78.5	8.41	1.31	1.42	5848
Column temperature (°C)	25	100.1	8.22	1.30	1.46	5828
	27	100.1	8.02	1.35	1.34	5856
	30	100.0	7.80	1.36	1.32	5944
Methanol in mobile phase	−0.2%	100.0	8.42	1.33	1.38	6002
	+0.2%	100.0	7.33	1.39	1.42	5549

: resolution; -D: tailing factor of the drug; -IS: tailing factor of the internal standard.