Preparation and characterization of solid lipid nanoparticles containing cyclosporine by the emulsification-diffusion method

Figures & data

Table 1 Mean particle size of empty SLNs prepared at RT (Gelucire^® = 400 mg) and at CT (Compritol^® = 200 mg), with 5% w/v PVAL; n = 3

	Mean particle size (nm) and polydispersity index
	Gelucire^®	Compritol^®
Batch 1	280.0 [0.220]	789.0 [0.524]
Batch 2	281.3 [0.283]	756.9 [0.509]
Batch 3	280.8 [0.316]	734.5 [0.481]
Mean	280.7a	760.1a
Standard deviation (σ)	0.65	27.30

a Notes: Exists statistical difference between means, P < 0.05; PDI values between brackets.

Table 2 Composition of the formulations, percentage (w/w) of CyA with respect to the weight of lipid, mean particle size, Z-potential and probable day of aggregation of SLNs prepared at RT (Gelucire^®) with 5% w/v PVAL

System	Gelucire (mg)	CyA (mg)	% CyA (w/w)	Particle size (nm)a	Z-potential (mV)a	Day of visible aggregation	Encapsulation efficiency (%)
Empty SLN	400	0	0.00	276.6 ± 5 [0.34]	23.70 ± 0.034	–	–
Batches containing only CyA	0	40	0.00	2510.0 ± 7 [0.87]	22.50 ± 0.196	11	–
A	400	20	5.00	256.4 ± 1 [0.36]	22.80 ± 0.014	69	99.18
B	400	25	6.25	346.1 ± 3 [0.28]	33.07 ± 0.024	80	99.15
C	400	30	7.50	310.5 ± 3 [0.22]	39.50 ± 0.150	64	99.13
D	400	40	10.00	248.3 ± 5 [0.15]	28.91 ± 1.257	78	99.02
E	400	50	12.50	320.8 ± 7 [0.18]	30.11 ± 1.361	20	98.45
F	400	60	15.00	459.3 ± 1 [0.48]	30.50 ± 0.032	12	98.19
G	400	120	30.00	375.7 ± 1 [0.65]	34.12 ± 0.048	4	95.26
H	400	200	50.00	478.3 ± 1 [0.73]	30.13 ± 3.841	2	92.74

a Notes: Reported as mean ± standard deviation; n = 3.

Figure 1 Scanning electron micrographs of loaded Gelucire^® 44/14 SLNs with different theoretical loadings (bar = 1 μm). A) CyA-Gelucire^® (20:400 mg; 5% CyA) t = 0; B) CyA-Gelucire^® (40:400 mg; 10% CyA) t = 0; C) CyA-Gelucire^® (30:400 mg; 7.5% CyA) t = 0; D) CyA-Gelucire^® (30:400 mg; 7.5% CyA) t = 4 months.

Figure 2 DSC thermograms of A) CyA; B) Gelucire^® 44/14; C) PVAL.

Figure 3 DSC thermograms of A) Physical mixture of CyA-Gelucire^® (40:400 mg w/w); B) Physical mixture of CyA-Gelucire^® (80:400 mg w/w); C) Physical mixture of CyA-Gelucire^® (200:400 mg w/w); D) Physical mixture of CyA-PVAL (20:100 mg w/w); E) Physical mixture of CyA-PVAL (80:100 mg w/w); and F) Physical mixture of CyA-PVAL (200:100 mg w/w).

Figure 4 DSC thermograms of A) and B) batches prepared with CyA only, t = 0 and t = 5 months respectively; C) and D) empty SLNs; t = 0 and t = 5 months respectively; E) and F) SLNs with 5% CyA (drug-lipid ratio 20:400 (w/w)), t = 0 and t = 5.5 months, respectively; G) and H) SLNs with 15% CyA (drug-lipid ratio 60:400 (w/w)), t = 0 and t = 5.5 months, respectively; I) and J) SLNs with 50% CyA (drug-lipid ratio 200:400 (w/w)), t = 0 and t = 5.5 months, respectively.

Figure 5 In vitro release of CyA and turbidity changes during this experiment.