Preparation and Characterisation of Phenytoin-Loaded Alginate and Alginate-Chitosan Microparticles

Figures & data

TABLE 1 Composition of model formulations of inhomogeneous microparticles prepared according to the one-stage procedure

Formulation	CaCl2 concentration (%, w/w)	Chitosan concentration (%, w/w)
F1	0.5	—
F2	1.0	—
F3	2.0	—
F4	0.5	0.1
F5	1.0	0.1
F6	2.0	0.1
F7	0.5	0.2
F8	1.0	0.2
F9	2.0	0.2
F10	0.5	0.4
F11	1.0	0.4
F12	2.0	0.4

FIG. 1 Particle size of alginate (F1–F3) and alginate-chitosan microparticles (F4–F12).

FIG. 2 Photomicrograph of formulations F3 before (left) and after drying (right).

FIG. 3 Photomicrograph of formulations F12 before (left) and after drying (right).

TABLE 2 Drug loading of 12 (F1–F12) studied model formulations

Formulation	Drug loading (%)
F1	92.84 ± 2.97
F2	95.33 ± 3.09
F3	95.50 ± 3.14
F4	96.02 ± 4.10
F5	96.25 ± 2.08
F6	96.34 ± 1.99
F7	90.63 ± 3.87
F8	93.91 ± 4.58
F9	95.88 ± 2.73
F10	96.15 ± 3.79
F11	93.01 ± 2.88
F12	95.12 ± 3.95

FIG. 4 Photomicrograph of phenytoin particles in alginate suspension.

FIG. 5 Release profiles of phenytoin from alginate and alginate-chitosan microparticles.

TABLE 3 Times for 50% and 90% of the drug to be released, t_50% and t_90%, respectively

Formulation	t50% (min)	t90% (min)
F1	72,98	157,54
F2	63,50	137,85
F3	50,79	125,00
F4	83,45	163,45
F5	68,29	146,88
F6	57,12	147,01
F7	114,79	219,50
F8	59,62	143,30
F9	53,48	130,55
F10	76,48	166,77
F11	68,02	155,93
F12	34,17	129,41

FIG. 6 (a) Release profiles of phenytoin from alginate and alginate-chitosan microparticles. (b) Effect of chitosan concentration on release characteristics of alginate-chitosan microparticles. (c) Effect of calcium chloride concentration on release characteristics of alginate and alginate-chitosan microparticles.

FIG. 7 Effect of preparation procedure on release characteristics of alginate-chitosan microparticles. F1 and F7 are prepared according to the one-stage procedure; F7a and F7b, according to the two-stage procedure.