Table 4.

Descriptive statistic regarding stability testing of five types of standard with different lyophilisation matrix.

	A	B	C	D	E
Variance	0.153	0.036	0.183	0.079	0.117
R2 of model	0.556	0.763	0.929	0.641	0.724
Mean	4.662	5.542	5.036	4.942	5.094
SD	0.249	0.104	0.218	0.170	0.191
Coeff. of variation (%)	5.35	1.87	4.32	3.43	3.75