Table 1.

Validation parameters for ephedrine, glycyrrhizic acid and amygdalin by high performance liquid chromatography

Compound	Concentration range (μg/mL)	R2	Linear regression	Intra-D (%)	Inter-D (%)
Ephedrine	6.25–100	0.997	Y = 0.454x-0.0356	1.00–2.74	0.98–3.02
Glycyrrhizic acid	6.25–100	0.999	Y = 0.052x + 0.0046	0.34–3.76	0.62–2.84
Amygdalin	6.25–100	0.990	Y = 0.0645x + 0.0788	1.61–4.33	1.48–3.67