Chemically Cross-Linked Poly(acrylic-co-vinylsulfonic) Acid Hydrogel for the Delivery of Isosorbide Mononitrate

Table 3

Drug release kinetics of poly(AA-co-VSA) hydrogels in solutions of different pHs.

Sample	pH	Zero-order kinetics		First-order kinetics		Higuchi model		Korsmeyer-Peppas model
		𝐾0 (h^−1)	𝑅^2	𝐾1 (h^−1)	𝑅^2	𝐾2 (h^−1)	𝑅^2	𝑛	𝑅^2	Release mechanism
S1	1.2	2.4370	0.9861	0.0292	0.9925	0.1039	0.9838	0.8399	0.9939	Non-Fickian
	5.5	6.0195	0.9675	0.1081	0.9982	0.2605	0.9952	0.9051	0.9865	Non-Fickian
	7.5	7.2830	0.9495	0.1840	0.9914	0.3181	0.9952	0.8515	0.9797	Non-Fickian
S2	1.2	2.2615	0.9848	0.0268	0.9931	0.0969	0.9928	0.8150	0.9977	Non-Fickian
	5.5	5.7970	0.9840	0.0982	0.9980	0.2482	0.9908	0.9231	0.9950	Non-Fickian
	7.5	6.8438	0.9750	0.1504	0.9766	0.2951	0.9961	0.8691	0.9892	Non-Fickian
S3	1.2	1.9763	0.9662	0.0232	0.9766	0.0855	0.9927	0.7735	0.9884	Non-Fickian
	5.5	5.3641	0.9385	0.0894	0.9866	0.2353	0.9917	0.9122	0.9667	Non-Fickian
	7.5	6.4905	0.9375	0.1383	0.9968	0.2851	0.9939	0.8438	0.9662	Non-Fickian
S4	1.2	1.8342	0.9438	0.0212	0.9570	0.0802	0.9914	0.7869	0.9840	Non-Fickian
	5.5	4.8496	0.9626	0.0749	0.9929	0.2106	0.9969	0.9211	0.9746	Non-Fickian
	7.5	6.3101	0.9885	0.1181	0.9888	0.2695	0.9907	0.9147	0.9947	Non-Fickian
S5	1.2	1.8812	0.9704	0.0219	0.9813	0.0184	0.9980	0.7669	0.9876	Non-Fickian
	5.5	5.4079	0.9664	0.0874	0.9964	0.2340	0.9939	0.9493	0.9846	Non-Fickian
	7.5	6.4510	0.9735	0.1308	0.9934	0.2786	0.9977	0.8571	0.9864	Non-Fickian
S6	1.2	2.1164	0.9762	0.0249	0.9856	0.0910	0.9923	0.8174	0.9921	Non-Fickian
	5.5	5.2759	0.9515	0.0884	0.9923	0.2304	0.9965	0.8545	0.9754	Non-Fickian
	7.5	6.4930	0.9748	0.1348	0.9816	0.2800	0.9961	0.8392	0.9898	Non-Fickian