Use of Natural Gums and Cellulose Derivatives in Production of Sustained Release Metoprolol Tablets

Figures & data

TABLE 1 Different formulations of metoprolol matrix tablets based on natural gums or cellulose derivatives

	Ingredients (mg)
Formulation code	Metoprolol tartrate	HPMC	NaCMC	Guar	Xanthan	Magnesium stearate	Aerosil	Titanium dioxide	Avicel PH101
H1	100	120	—	—	—	2	2	6	90
H2	100	96	24	—	—	2	2	6	90
H3	100	72	48	—	—	2	2	6	90
H4	100	48	72	—	—	2	2	6	90
G1	100	—	—	120	—	2	2	6	90
G2	100	—	—	96	24	2	2	6	90
G3	100	—	—	72	48	2	2	6	90
G4	100	—	—	48	72	2	2	6	90
G5	100	—	—	—	120	2	2	6	90

FIG. 1 Metoprolol release profiles from different tablets based on (a) cellulose derivatives and (b) mixtures of natural gums, compared with the standard Lopressor tablets (ST) (n=3).

TABLE 2 Comparison of release parameters and diffusion exponent (n) of Peppas equation for Lopressor (ST) and different formulations of metoprolol matrix tablets based on natural gums or cellulose derivatives

Formulation code	MDT ± SD (hr)	DE8 ± SD(%)	f2	n ± SD
ST	5.246 ± 0.196	63.928 ± 0.192	—	0.673 ± 0.026
H1	3.533 ± 0.125	92.823 ± 0.181	34.95	0.686 ± 0.027
H2	3.780 ± 0.189	90.236 ± 0.191	36.23	0.768 ± 0.020
H3	5.669 ± 0.206	65.663 ± 0.391	64.13	0.735 ± 0.003
H4	6.232 ± 0.032	41.711 ± 0.085	39.25	0.690 ± 0.015
G1	3.147 ± 0.014	97.201 ± 0.126	31.54	0.833 ± 0.025
G2	3.688 ± 0.241	88.132 ± 0.142	38.04	0.891 ± 0.014
G3	5.114 ± 0.313	71.197 ± 0.190	54.76	0.920 ± 0.009
G4	6.204 ± 0.216	59.288 ± 0.401	54.12	1.095 ± 0.019
G5	6.304 ± 0.381	55.438 ± 0.146	54.75	1.140 ± 0.025

(MDT = mean dissolution time; DE₈% = dissolution efficiency until 8 hr; f₂ = similarity factor) (n = 3).

TABLE 3 Regression analysis (r²) of release data based on best curve-fitting method for Lopressor (ST) and different formulations of metoprolol matrix tablets based on natural gums or cellulose derivatives (n = 3)

Formulation code	Zero-order	First-order	Higuchi	Hixon-Crowell
ST	0.976 ± 0.002	0.941 ± 0.015	0.970 ± 0.005	0. 970 ± 0.010
H1	0.929 ± 0.003	0.958 ± 0.007	0.991 ± 0.001	0.987 ± 0.013
H2	0.953 ± 0.006	0.946 ± 0.007	0.985 ± 0.002	0.975 ± 0.009
H3	0.977 ± 0.003	0.812 ± 0.040	0.952 ± 0.006	0.910 ± 0.022
H4	0.961 ± 0.009	0.923 ± 0.017	0.921 ± 0.006	0.941 ± 0.013
G1	0.904 ± 0.001	0.964 ± 0.013	0.981 ± 0.003	0.971 ± 0.029
G2	0.942 ± 0.004	0.960 ± 0.019	0.983 ± 0.001	0.974 ± 0.015
G3	0.970 ± 0.004	0.899 ± 0.015	0.962 ± 0.007	0.974 ± 0.015
G4	0.986 ± 0.004	0.819 ± 0.030	0.911 ± 0.012	0.899 ± 0.035
G5	0.985 ± 0.002	0.860 ± 0.027	0.908 ± 0.006	0.929 ± 0.011

FIG. 2 Water uptake of metoprolol matrix tablets based on (a) cellulose derivatives and (b) natural gums (n=3).

FIG. 3 Erosion percentage of metoprolol tablets based on (a) cellulose derivatives and (b) natural gums (n=3).