Tailoring of locust bean gum and development of hydrogel beads for controlled oral delivery of glipizide

Figures & data

Table 1.  Effect of AlCl₃ concentration of percentage yield, particle size, and drug entrapment efficiency of CMLBG beads loaded with 30% (w/w) glipizide.

CMLBG (%w/v)	Gelation time (min)	% (w/v) of AlCl3	% Yield	Arithmetic mean diameter (× 10^3 µm)	Entrapment efficiency (%) ± SD, n = 3
4.0	15	1.0	93.35	1.24 ± 0.04	97.68 ± 0.84
4.0	15	3.0	94.65	1.25 ± 0.06	95.46 ± 1.07
4.0	15	5.0	94.80	1.27 ± 0.05	95.14 ± 1.01

Figure 1.  FTIR spectrum of (a) locust bean gum; (b) sodium carboxymethyl locust bean.

Figure 2.  Probable carboxym ethylation reaction pathways of locust bean gum.

Figure 3.  Scanning electron micrographs of blank and glipizide-loaded CMLBG bead. Key: Concentration of aluminium chloride: (a) 5% (blank bead); (b) 1%; (c) 3%; (d) 5%.

Table 2.  Release characteristics and mathematical modeling of the release data of glipizide-loaded CMLBG beads in pH 7.4 phosphate buffer solution.

%w/v of AlCl3	t50% (min) in phosphate buffer (pH 7.4)	t80% (min) in phosphate buffer (pH 7.4)	Korsmeyer-Peppas model
			k	n	*r^2
1.0	151.67 ± 28.75	434.83 ± 20.40	0.0194	0.6374	0.9939
3.0	290.83 ± 20.36	556.67 ± 54.84	0.0172	0.5931	0.9965
5.0	327.50 ± 11.46	600.83 ± 8.03	0.0109	0.6642	0.9930

* Correlation coefficient.

Figure 4.  Release profiles of glipizide-loaded beads in different dissolution media. Drug release in pH 7.4 phosphate buffer solution; Key: Concentration of aluminium chloride: (Δ) 1%; (□) 3%; (○) 5%. Drug release in pH 1.2 KCl-HCl buffer solution; Key: Concentration of aluminium chloride: (▴) 1%; (▪) 3%; (•) 5%.

Figure 5.  Swelling study of blank beads in different dissolution media. Swelling study in pH 1.2 KCl-HCl buffer solution; Key: Concentration of aluminium chloride: (Δ) 1%; (□) 3%; (○) 5%. Swelling study in pH 7.4 phosphate buffer solution; Key: Concentration of aluminium chloride: (▴) 1%; (▪) 3%; (•) 5%.

Figure 6.  DSC thermograms and TGA curves of blank beads prepared using different concentrations of aluminium chloride. Key: Concentration of aluminium chloride: (a) 1%; (b) 3%; (c) 5%.

Figure 7.  Release profile of glipizide-loaded beads (5% aluminium chloride) in pH 7.4 phosphate buffer solution following dissolution in pH 1.2 KCl/HCl buffer solution for 2 h.

Figure 8.  FTIR spectra of (a) blank beads; (b) pure glipizide; (c) glipizide-loaded beads; (d) physical mixture of glipizide and CMLBG.

Figure 9.  DSC thermograms of pure glipizide (bold dotted line), physical mixture of drug and polymer (faint dotted line), and glipizide-loaded beads (bold continuous line).

Figure 10.  X-Ray diffraction pattern of (a) pure glipizide; (b) physical mixture; (c) glipizide-loaded CMLBG beads.

Figure 11.  In vivo anti-diabetic activity of 5% (w/v) aluminium chloride treated glipizide-loaded beads in male Wistar rats.