Highly Porous pH-Responsive Carboxymethyl Chitosan-Grafted-Poly (Acrylic Acid) Based Smart Hydrogels for 5-Fluorouracil Controlled Delivery and Colon Targeting

Table 5

Effect of different concentration of AA on the drug release kinetics of Poly (CMCS-g-AA) hydrogels in solutions of different pH using EGDMA as crosslinking agent (0.7% of AA).

Samples code	AA contents	pH	Zero-order kinetics		First-order kinetics		Higuchi model
			K0 (h^−1)		K1 (h^−1)		K2 (h^−1)
HS1	25.45	1.2	1.59	0.99	0.018	0.99	0.068	0.982
		6.5	5.37	0.97	0.087	0.98	0.232	0.996
		7.5	6.52	0.98	0.125	0.99	0.279	0.991
HS2	32.72	1.2	1.70	0.98	0.019	0.98	0.072	0.990
		6.5	5.69	0.98	0.094	0.99	0.244	0.991
		7.5	6.76	0.99	0.133	0.97	0.287	0.981
HS3	40	1.2	1.82	0.95	0.021	0.96	0.079	0.992
		6.5	5.78	0.95	0.103	0.99	0.252	0.996
		7.5	6.66	0.93	0.149	0.99	0.292	0.992