Table 1.

Coefficients and ANOVA statistical analysis for the three studied factors of the optimization design. (M, metformin; L, linagliptin; E, empagliflozin; Asym, asymmetry; t_R, retention time; NTP, number of theoretical plates; Rs, resolution; A, %MeOH; B, buffer pH; C, buffer concentration; AB, %MeOH-buffer pH interaction; AC, %MeOH-buffer concentration interaction; A², B² and C², the quadratic terms of the corresponding factors.)

	A	B	C	AB	AC	A²	B²	C²
Rs 1	−0.47	−0.10		0.04				−0.07
p-values	<0.0001	<0.0001		0.0403				0.0004
Rs 2	−0.47	−0.32	0.27		−0.09	−0.05	−0.08	0.18
p-values	<0.0001	<0.0001	<0.0001		0.0167	0.024	0.013	<0.0001
NTP (LIN)	464.77	−181.50	38.88	49.71		41.86	59.91
p-values	<0.0001	<0.0001	0.0241	0.034		0.0117	0.0059
ASM LIN	0.02		−0.04	0.04	−0.07	0.07	0.05	0.10
p-values	0.0129		0.0002	0.0009	<0.0001	<0.0001	<0.0001	<0.0001