Preparation and optimization of quercetin-loaded liposomes for wound healing, using response surface methodology

Figures & data

Table I. Independent variables along with their coded level, actual level, and respective response values of different batches of quercetin-loaded liposomes.

	Coded level		Actual level		Responses			Polydispersity Index (PDI)	Zeta Potential (mV)
Form code	X1	X2	X1	X2	Drug Release (%)	Particle Size (nm)	Entrapment Efficiency (%)
Q1	− 1	− 1	40	50	75.09	591.9	69.4	0.372 ± 0.032	− 16.3±(− 1.43)
Q2	0	− 1	45	50	60.32	213.6	76.3	0.289 ± 0.214	− 17.7±(− 2.36)
Q3	1	− 1	50	50	71.51	425.7	78.5	0.248 ± 0.024	− 14.2±(− 5.47)
Q4	− 1	0	40	75	69.55	418.1	71.8	0.265 ± 0.321	− 14.1±(− 4.61)
Q5	0	0	45	75	58.55	158.2	78.3	0.145 ± 0.025	− 14.2±(− 1.32)
Q6	1	0	50	75	66.51	334.3	86.5	0.067 ± 0.326	− 10.6±(− 1.25)
Q7	− 1	1	40	100	66.23	395.1	54.6	0.128 ± 0.245	− 13.9±(− 2.87)
Q8	0	1	45	100	57.15	146.8	59.2	0.250 ± 0.347	− 12.5±(− 6.02)
Q9	1	1	50	100	64.45	303.9	70.3	0.345 ± 0.478	− 11.6±(− 6.24)

Table II. Summary of results of regression analysis of responses and analysis of variance for drug release, particle size, and EE.

Parameters	DF	SS	MS	F	P value	R^2	SD	Coeff. of variance (%)
Drug Release (%)
Model	5	283.77	56.75	20.68	0.0157 Significant	0.9718	1.66	2.53
Residual	3	8.23	2.74
Total	8	292.00
Mean Particle Size
Model	5	1.631E + 005	32618.32	24.77	0.0121 Significant	0.9764	36.29	10.93
Residual	3	3949.82	1316.61
Total	8	1.670E + 005
% Entrapment Efficiency
Model	5	773.61	154.72	37.77	0.0065 Significant	0.9844	2.02	2.82
Residual	3	12.29	4.10
Total	8	785.90

Table III. Comparison of the observed and predicted values for the liposomes prepared under predicted optimum conditions.

		Predicted optimum range
S. No.	Responses variable	X1	X2	Predicted value	Observed value	Bias %
1	% Drug Release	46	75	58.43	54.31	7.05
2	% EE	46	75	80.32	86.5	− 7.69
3	Mean particle size (nm)	46	75	146.8	143.6	2.179

Figure 1. Surface plots showing the effect of variables on (A) particle size, and (B) % Entrapment Efficiency, and (C) % Drug Loading.

Figure 2. DSC thermograms of quercetin, cholesterol and physical mixture.

Figure 3. TEM image of optimized quercetin-loaded liposome.

Figure 4. Release profile of the optimized quercetin-loaded liposome in phosphate buffer of pH 7.4, at 37°C.