The Specificity of the method was established by injecting a Blank, (diluent) Placebo and Sample preparation into the chromatograph. The chromatograms of blank, standard and sample (prepared from formulation) solutions were compared. No interference was observed. This indicates that the solvent and excipients from capsule formulation do not interfere at the retention time of drug peak and shows a good resolution.
LinearityThe peak area responses of all solutions over concentration levels ranging from 40% to 160% of target concentration were measured in triplicate. A linear correlation was observed between peak areas and the concentrations. The linearity of the calibration curve was validated by the value of correlation coefficients of the regression (r= 0.9999) and good correlation was obtained between the peak area and concentration as shown in figure 3The accuracy of the method was determined by recovery experiments and was performed in triplicate by the standard addition method at 80%, 100% and 120% of test concentration and analysis precision was expressed as % RSD. A known amount of measuring analyte was added to placebo preparations and was subjected to the proposed UPLC method. Results of recovery studies are shown in Table 3.
The mean percentage recovery was 101.7% and % RSD was found to be less than 1.0%.
The slope of Erythromycin estolate was 1.02 from 10% to 150% of Accuracy levels and the confidence level, 95% of the accuracy of the method was 0.32. The results are shown in table 3
