The filtrate was diluted suitably with methanol to get a final solution of 5 ��g/ml concentration. This was third subsequently analyzed for OLM using a double beam UV-VIS spectrophotometer and methanol as the blank. The drug content of the sample was calculated using the standard calibration curve. Method validation Validation is a process of establishing documented evidence, which provides a high degree of assurance that a specific activity will consistently produce a desired result, or a product meeting its predetermined specifications and quality characteristics. The method was validated for different parameters like Linearity, Accuracy, Precision, Specificity, Robustness, Ruggedness, Limit of Detection (LOD), and Limit of Quantification (LOQ).

Linearity Various aliquots were prepared from the stock solution (100 ��g/ml) ranging from 2 �C 20 ��g/ml. The samples were analyzed with the help of a UV-VIS Spectrophotometer, using methanol as the blank. The linearity of the above-mentioned sample can be observed in Table 2. Table 2 Linearity in working standards Accuracy The accuracy of the method was determined by preparing solutions of different concentrations, that is, 80, 100, and 120%, in which the amount of marketed formulation (Benicar?) was kept constant (5 mg) and the amount of pure drug was varied, that is, 4 mg, 5 mg, and 6 mg for 80, 100, and 120%, respectively. The solutions were prepared in triplicate and the accuracy was indicated by % recovery [Table 3]. Table 3 Determination of accuracy by the percentage recovery method Precision The precision of the method was demonstrated by intra-day and inter-day variation studies.

In the inter-day variation study, the solutions of same concentration (12 ��g/ml) were prepared and analyzed thrice, for three consecutive days, and the absorbances were recorded [Tables [Tables44 and and5].5]. In the intra-day variation study, nine different solutions of the same concentration (12 ��g/ml) were prepared and analyzed thrice a day (morning, afternoon, and evening). The result was indicated by % RSD [Table 6]. Table 4 Precision results showing repeatability of Olmesartan medoxomil Table 5 Intra-assay study Table 6 Inter-assay study Specificity Olmesartan medoxomil of 5 mg was spiked with 50% (5 mg), 100% (10 mg), and 150% (15 mg) of excipient mix (Magnesium Stearate) and the sample was analyzed for % recovery of OLM [Table 7].

Table 7 Test for specificity Ruggedness The ruggedness of the method was determined by carrying out the analysis using two different analysts and the respective absorbances were noted. The results are indicated in Table 8. Table 8 Ruggedness study Limit of detection The limit of detection (LOD) was determined by preparing solutions of different concentrations ranging from AV-951 0.1 �C 0.5 ��g/ml. The detection limit of an individual analytical procedure is the lowest amount of analyte in a sample, which can be detected, but not necessarily quantitated as an exact value.