Table 2. The estabolished HPLC methods.

Drug	Mobile phase (v/v)	Flow rate (mL/min)	Detection (nm)
Phenylbutazone	Water-methanol (25:75)	0.7	238
Diazepam	Water-methanol (25:75)	0.7	242
Digitoxin	Water-acetonitrile (55:45)	1	220
Ketoprofen	Phosphate buffer (0.01 mol/L, pH 4.5)-acetonitrile (40:60)	0.8	250
Mexiletine	Phosphate buffer (0.02 mol/L, pH 5.5)-acetonitrile (75:25)	0.9	214