Novel pH sensitive composite hydrogel based on functionalized chitosan/clay for the controlled release of a calcium channel blocker

Figures & data

Figure 1. Structure of diltiazem hydrochloride.

Figure 2. Schematic representation of the formation of OA-g-CS/MMT composites.

Table 1. Optimisation of drug encapsulation.

pH	Drug loaded (%)
4.0	48
5.0	62
6.0	51
7.0	49
8.0	38

Figure 3. FT-IR spectra of CS, OA-g-CS and OA-g-CS/MMT.

Figure 4. XRD spectra of OA-g-CS/MMT composites.

Figure 5. SEM micrographs of OA-g-CS/MMT composites.

Figure 6. AFM (3-D) images of MMT, OA-g-CS, drug loaded OA-g-CS/MMT composites.

Figure 7. Effect of MMT content on the swelling ratios of OA-g-CS/MMT composites.

Figure 8. Swelling ratios of the composites as a function of pH.

Figure 9. Release profile of DTZ from the composites at pH 7.4.

Figure 10. Release profile of DTZ from the composites at pH 1.2.

Table 2. Values of n for different drug loadings at pH 1.2 and pH 7.4.

pH	Drug loaded (%)	n
1.2	5	0.56
	10	0.64
	15	1.36
	20	1.45
	25	1.66
7.4	5	0.73
	10	0.75
	15	0.78
	20	0.79
	25	0.81

Figure 11. Comparison of the antimicrobial activities of CS, OA-g-CS and OA-g-CS/MMT composites.