Collaboration between HPMC and NaCMC in order to Reach the Polymer Critical Point in Theophylline Hydrophilic Matrices
Table 1
Kinetic parameters for the zero-order, Higuchi, Korsmeyer, and Peppas-Sahlin models calculated for the binary and ternary hydrophilic matrix tablets.
Zero order
Higuchi
Korsmeyer
Peppas and Sahlin
Batch
%w/w Drug
%w/w HPMC
%w/w NaCMC
(%minβ1)
r
2
b (%minβ1/2)
r
2
k (%minβn )
n
r
2
(%minβm )
(%minβ2m )
r
2
10
60
40
0
0.078
0.982
2.127
0.978
0.553
0.703
0.998
0.927
0.107
0.998
14
70
30
0
0.108
0.987
2.406
0.938
0.354
0.819
0.997
0.524
0.159
0.997
17
80
20
0
0.270
0.994
4.693
0.960
1.696
0.679
0.994
2.311
0.254
0.996
19
90
10
0
0.350
0.979
5.585
0.995
2.019
0.676
0.999
2.627
0.307
0.999
6
60
0
40
0.429
0.927
7.934
0.880
0.002
2.025
0.999
β4.582
0.97
0.973
11
70
0
30
0.329
0.992
6.804
0.961
0.058
1.305
0.999
β2.414
0.648
0.998
15
80
0
20
0.425
0.999
8.047
0.981
0.119
1.231
0.999
β2.453
0.781
>0.999
18
90
0
10
0.465
0.956
5.268
0.911
0.015
1.816
0.999
β7.453
1.801
0.985
1
40
10
50
0.146
0.997
4.347
0.966
0.06
1.139
0.999
β1.741
0.453
0.999
2
40
20
40
0.113
0.988
3.492
0.986
0.206
0.906
0.997
β0.418
0.304
0.998
3
50
10
40
0.170
0.994
4.766
0.977
0.111
1.064
0.997
β1.235
0.38
0.998
4
50
20
30
0.132
0.977
4.123
0.987
0.273
0.887
0.995
β0.066
0.256
0.995
5
50
30
20
0.150
0.999
4.210
0.967
0.083
1.097
>0.999
β1.171
0.384
0.999
7
60
10
30
0.151
0.960
6.222
0.880
0.023
1.299
0.988
β1.54
0.323
0.984
8
60
20
20
0.187
0.994
4.447
0.955
0.12
1.076
0.998
β0.86
0.372
0.997
9
60
30
10
0.226
0.981
4.082
0.905
0.032
1.33
0.998
β2.501
0.556
0.993
12
70
10
20
0.286
0.997
6.070
0.977
0.156
1.108
0.999
β1.175
0.527
0.999
13
70
20
10
0.337
0.931
6.735
0.857
0.004
1.811
0.995
β3.88
0.775
0.975
16
80
10
10
0.340
0.978
7.023
0.942
0.085
1.247
0.994
β2.01
0.628
0.992
(%minβ1): zero-order constant; b (%minβ1/2): Higuchiβs slope; (%minβn ): kinetics constant of the Korsmeyer model, : diffusional exponent, : diffusional constant of Peppas and Sahlin model, : relaxation constant of Peppas and Sahlin model, m: exponent that depends on the geometric shape of the releasing device through its aspect ratio].