A 1⁄4 298:38C2 þ 5131:6C þ 581:66 r 1⁄4 0:9999 for ISO at 215 nm
A1⁄46248:2Cþ298:87 r1⁄41 for DIF at 237nm
where, ‘‘A” is the peak area. ‘‘C” is the concentration in
lg spot 1 and ‘‘r” is the regression coefficient. 4. Methods validation
Method validation was performed according to ICH guideline9 for the proposed methods as follows:
4.1. Range and linearity
The linearity of the proposed methods was evaluated by pro- cessing the different calibration curves on three different days. The calibration curves were constructed within concentration ranges that were selected on the basis of the anticipated drug concentration during the assay of the dosage form. Each con- centration was repeated three times. The linear regression equations are summarized in Table 2. The corresponding con- centration ranges, calibration equations and other statistical parameters for all methods are listed in Table 2.
4.2. Accuracy
To study the accuracy of the proposed methods, procedures under linearity for the drugs were repeated three times for the determination of six different concentrations of pure MIC, MF, and GEN. The accuracy expressed as percentage recoveries is shown in Table 2. The standard addition tech- nique presented in Table 3 showed no interference o