Table 1.

Composition of the Independent Variables with Their Respective Levels and Their Dependent Variables

Variables	Levels
Independent variables (Factors)	Low(−1)					Medium(0)			High(+1)
A = PC concentration % (w/v)	1%					2%			3%
B = Ethanol concentration % (v/v)	10%					20%			30%
C = PG concentration % (v/v)	5%					10%			15%
Formula no.	Independent variables			Dependent variables							PDI
	A	B	C	Y1: particle size (nm)	Y2: zeta potential(mV)		Y3:EE%	Y4: % drug released over 24h		Y5: % drug permeated over 24h
F1	+1	+1	0	354.3±9.36	−77.5±3.99		98.86±5.01	83.69±8.29		74.26±5.92	0.46
F2	0	−1	−1	340±4.35	−61.1±4.32		89.23±4.88	67.2±6.38		55.16±5.28	0.43
F3	0	0	0	271.4±6.48	−59.5±4.28		93.81±3.74	76.73±4.41		73.5±6.99	0.35
F4	0	−1	+1	311±8.27	−54.5±7.84		92.76±6.55	73.23±11.01		61.38±3.09	0.30
F5	−1	+1	0	174.5±5.36	−56.1±2.09		91.24±7.98	97.9±3.92		85.18±5.61	0.26
F6	+1	−1	0	404±10.43	−66.3±5.82		95.84±4.72	62.48±8.54		51.53±4.33	0.36
F7	+1	0	+1	367.6±13.49	−72.6±9.75		98.27±3.91	75.4±4.09		63.28±4.72	0.37
F8	−1	−1	0	310.1±3.52	−51±8.35		82.01±6.02	79.87±2.74		68.38±9.51	0.39
F9	+1	0	−1	386.4±5.33	−74.2±3.17		97.97±7.53	70.43±10.61		58.83±6.42	0.34
F10	0	0	0	283.5±6.63	−62±5.29		95.09±11.23	78.83±6.81		68.87±3.99	0.46
F11	0	+1	+1	237.4±3.81	−67±10.56		96.39±2.84	93.87±8.49		83.28±5.91	0.33
F12	0	+1	−1	261.3±2.69	−72.6±3.88		96.03±3.52	87.9±7.90		76.94±8.53	0.36
F13	−1	0	−1	228.4±11.51	−52.3±3.11		84.12±9.19	82.24±14.73		72.38±7.28	0.32
F14	−1	0	+1	199.4±3.33	−58.2±4.02		87.13±4.92	89.24±5.44		78.53±4.74	0.26
F15	0	0	0	293.6±9.46	−60.6±6.53		93.91±3.06	75.49±5.38		71.32±5.26	0.21
F optimized	1.33%	30%	15%	195.8±5.45	−62.1±2.85		92.63±4.33	96.63±6.81		85.98±4.79	0.37

Note: Data are mean values (n = 3) ± SD.

Abbreviations: PC, Phosphatidyl choline; PG, Propylene glycol; EE%, entrapment efficiency percent; PDI, polydispersity index.