Characterization and In Vitro Sustained Release of Silibinin from pH Responsive Carbon Nanotube-Based Drug Delivery System

Table 2

Correlation coefficient (𝑅²) and rate constants (𝑘) obtained by fitting the silibinin release data for the COOH-MWCNTs in phosphate-buffered saline solutions at pH 7.4 and pH 4.8.

pH	Saturation release (%)	𝑅^2
		Pseudo-first order	Pseudo-second order	Parabolic diffusion	𝑘^∗ (mg/min)
7.4	96.6	0.9488	0.9980	0.7872	1.82 × 10^−4
4.8	43.1	0.7927	0.9955	0.8392	4.13 × 10^−4

∗Estimated using pseudo-second order kinetics.