Table 4.

Stability of metformin under various conditions at two concentrations (n = 3).

	LQC (15 ng/mL)	HQC (1600 ng/mL)
	% change
Autosampler for 24 h	5.00	13.74
One freeze-thaw cycle	7.46	8.76
Three freeze-thaw cycles	2.95	−9.49
Plasma at room temperature for 6 h	13.33	15.10
Stock at room temperature for 6 h	14.19	3.03