The results of the degradation studies indicate the specificity of the method since there was no interference from the sample, placebo and degrading peaks and also reveal that the method was selective and stability-indicating. The % assay of the drug was calculated after exposure of Erythromycin estolate solutions to various stress conditions. The drug undergoes degradation of oxidative and thermal/humidity stress conditions. The degrading peaks were well resolved from the drug peak. The drug was stable in thermal and photolytic conditions.
The validation of analytical method verifies that the characteristics of the method if they satisfy the requirements of the method. The proposed method was validated according to ICH guidelines for specificity, linearity, accuracy, and precision, and robustness. Specificity was carried out in which no interference of the excipients was observed at retention time of the analytical peak. Calibration curve was constructed by plotting concentration Vs plot area. It showed that there was a good linear relationship in the concentration range of 40% to 160% with > 0.999 as the value of correlation co-efficient. The accuracy of the method was studied by analyzing the drug solutions at 80%, 100% and120% concentration level. The mean percentage recovery was found to be 101.7% For precision the sample solution at working concentration was analyzed in replicate as per the method. The percentage relative standard deviation was found to be less than 1%. Robustness of the method shows no significant change in system suitability parameters and mean % assay at modifying chromatographic conditions from the original method