Caffeine-Loaded Niosomes: Characterization and in Vitro Release Studies

Figures & data

TABLE 1 Composition of caffeine loaded niosomes, mean volume diameter of vesicles, and caffeine encapsulation efficiency at different time intervals after preparation and storage at 4°C.

	Molar ratio			Mean volume
	(m.r.)			diameter (μ m) ± SD		Caffeine EE%^a ± SD
Surfactant name	Surfactant	CHOL^b	CTAB^c	72 h	3 months	72 h	3 months	Overall amount of drug released (%) ± SD
Span 20	7	3	0	22.10 ± 3.58	27.5 ± 4.3	78.73 ± 7.5	50.12 ± 11.33	26.12 ± 5.00
Span 40	7	3	0	13.15 ± 0.35	15.33 ± 1.36	71.69 ± 2.8	60.23 ± 8.32	25.84 ± 6.10
Span 60	7	3	0	11.89 ± 0.11	12.5 ± 0.52	81.75 ± 6.73	75.32 ± 9.17	22.33 ± 5.93
Span 80	7	3	0	8.89 ± 0.11	15.27 ± 0.63	38.49 ± 4.81	15.19 ± 5.89	31.99 ± 6.18
Span 20	5	3	2	7.18 ± 0.11	9.05 ± 0.42	52.41 ± 5.40	29.66 ± 6.95	33.25 ± 4.65
Span 40	5	3	2	12.00 ± 0.52	13.2 ± 0.98	49.56 ± 5.45	36.77 ± 7.23	30.00 ± 5.36
Span 60	5	3	2	11.30 ± 0.16	11.66 ± 0.79	50.56 ± 3.12	42.19 ± 8.12	29.42 ± 7.91
Span 80	5	3	2	6.81 ± 0.09	10.15 ± 1.22	30.44 ± 3.70	18.56 ± 9.75	43.21 ± 7.07

Overall percent of caffeine release from niosomal formulations at 32°C is also presented (mean ± SD, n = 3).

^aPercent of encapsulation efficiency; ^bCholesterol; ^cCetytrimethyl ammonium bromide.

FIGURE 1 Optical micrographs (× 1000 magnification) of caffeine-containing niosomes prepared by film hydration method. Niosomes were composed of (a) Span 20/CHOL/CTAB, (b) Span 60/CHOL, and (c) Span 40/CHOL. Scale bar = 10 μ m.

FIGURE 2 The vesicle size distribution of caffeine-containing niosomes prepared by film hydration method. Niosomes were composed of span 60/CHOL (7:3 m.r.) or span 60/CHOL/CTAB (5:3:2 m.r.).

FIGURE 3 The effect of surfactants HLB values on the mean volume diameter of neutral and positive niosomes.

FIGURE 4 Permeation profiles of caffeine through cellulose acetate after application of drug-containing neutral or positively charged niosomal formulations and free drug solution using Franz diffusion cells. Each point represents the mean ± SD (n = 3).

TABLE 2 Diffusion exponent (n) of Peppas model, calculated release rate (K) constants, and regression coefficient (r², in brackets) of caffeine release data from studied niosomes according to different kinetic models

Formulation	n	Baker-Lonsdale	Higuchi	Hixson-Crowell	First-order	Zero-order
Span20/CHOL^a	0.331	0.089 (0.935)	0.317 (0.827)	0.162 (0.952)	0.0004 (0.699)	0.095 (0.700)
Span40/CHOL	0.467	0.091 (0.948)	0.358 (0.794)	0.166 (0.955)	0.0005 (0.635)	0.106 (0.638)
Span60/CHOL	0.476	0.092 (0.901)	0.380 (0.815)	0.169 (0.937)	0.0005 (0.640)	0.112 (0.649)
Span80/CHOL	0.438	0.095 (0.970)	0.397 (0.920)	0.166 (0.992)	0.0005 (0.803)	0.123 (0.805)
Span20/CHOL/CTAB^sb	0.344	0.086 (0.870)	0.337 (0.836)	0.143 (0.911)	0.0004 (0.657)	0.101 (0.659)
Span40/CHOL/CTAB	0.458	0.078 (0.941)	0.365 (0.796)	0.132 (0.918)	0.0005 (0.646)	0.108 (0.649)
Span60/CHOL/CTAB	0.477	0.091 (0.932)	0.399 (0.868)	0.152 (0.966)	0.0005 (0.714)	0.121 (0.714)
Span80/CHOL/CTAB	0.445	0.087 (0.992)	0.381 (0.919)	0.147 (0.980)	0.0005 (0.761)	0.116 (0.771)

^aCholesterol, ^bCetytrimethyl ammonium bromide.