Table 2. Central composite design (decoded and coded variables) and responses obtained (area for each derivatization product), and desirability calculated.

	Molar ratio	Time ultrasonic bath (min)	7-dehydrocholesteryl-N-benzoylcarbamate	Cholesteryl-N-benzoylcarbamate	Coprostanolyl-N-benzoylcarbamate	Global desirability (D)
1	0.021	10	2107	3070	4675	0.0295
	(−1)	(−1)	0.0559	0.0202	0.0228
2	0.021	50	4580	5134	6518	0.1712
	(−1)	(+1)	0.3484	0.1662	0.0867
3	0.059	10	7831	10280	15351	0.5345
	(+1)	(−1)	0.7329	0.5301	0.3930
4	0.059	50	8653	12055	12121	0.5348
	(+1)	+1	0.8301	0.6557	0.2810
5	0.04	30	8892	12452	31745	0.8301
	(0)	(0)	0.8702	0.6837	0.9615
6	0.04	30	9957	16923	31961	0.9844
	(0)	(0)	0.9843	1	0.9690
7	0.04	30	10089	13048	32853	0.8987
	(0)	(0)	1	0.7259	1
8	0.067	30	7048	11309	14 717	0.5232
	(√2)	(0)	0.6403	0.6029	0.3710
9	0.04	58.28	7173	7724	10697	0.3756
	(0)	(√2)	0.6551	0.3493	0.2316
10	0.013	30	2634	3331	4352	0.0376
	(−√2)	(0)	0.1182	0.0386	0.0116
11	0.04	2.11	1634	2784	4017	0.0000
	(0)	(−√2)	0.0000	0.0000	0.0000