Time (min)
Calibration equation
Correlation coefficient (r)
Betahistine dihydrochloride
10
A = 0.119 + 0.085 C
0.9947
20
A = 0.155 + 0.101 C
0.9950
30
A = 0.189 + 0.107 C
0.9999
40
A = 0.089 + 0.114 C
0.9983
Etilefrine hydrochloride
10
A = -0.045 + 0.055 C
0.9928
20
A = -0.050 + 0.068 C
0.9981
30
A = -9.05 x 10
^{-5}
+ 0.069 C
0.9998
40
A = -0.053 + 0.062 C
0.9975
Table 3:
Calibration equations for betahistine dihydrochloride and etilefrine hydrochloride at different fixed times over the linearity range for both drugs, in presence of constant concentration of NBD-Cl.