All critical parameters tested met the acceptance criteria. Imatinib Mesylate side effects Specificity Specificity is the ability of the method to measure the analyte response in the presence of its potential impurities and degradation products. Placebo interference was evaluated by analyzing the placebo prepared as per the test method. No peak due to placebo detected at the retention time of guaifenesin and its impurities. The specificity of the developed LC method for guaifenesin was carried out in the presence of its impurities and degradation products. Stress studies were performed at 2.4 mg/mL concentration of guaifenesin on tablet to provide an indication of the stability-indicating property and specificity of proposed method.

The stress conditions employed for degradation study included acid hydrolysis (1 N HCl at 60��C for 12 h), base hydrolysis (1 N NaOH at 60��C for 12 h), oxidation (1% H2O2 at room temperature for 12 h), hydrolytic (water at 60��C for 12 h), thermal (105��C for 24 h), and photolytic degradation (drug product exposed to visible light for 240 h resulting an overall illustration 1.2 million lux hours and UV light for 250 h resulting an overall illustration 200 watt h/m2 at 25��C). Sight degradation was observed under acid and base stress conditions [Figures [Figures22 and and3].3]. Guaifenesin found stable under oxidative, hydrolytic, thermal, and photolytic stress conditions. The peak purity test was carried out for the guaifenesin peak by using the PDA detector in stress samples. The mass balance (% assay + % sum of all degradants + % sum of all impurities) results were calculated and found to be more than 95% [Table 1].

The purity of guaifenesin was unaffected by the presence of its impurities and degradation products, and thus confirms the stability-indicating power of the developed method. Figure 2 Typical chromatogram of the acid degradation sample Figure 3 Typical chromatogram of the base degradation sample Table 1 Summary of forced degradation results Precision The precision of method was verified by repeatability and intermediate precision. Repeatability was checked by injecting six individual preparations of guaifenesin tablets spiked with its two impurities, ��-isomer and guaiacol at 1.0% and 0.05% level, respectively (1.0% and 0.05% of impurities with respect to 2.4mg/ mL guaifenesin). The intermediate precision of the method was also evaluated using different analyst, different instrument, and performing the analysis on different days. The % RSD for the area of ��-isomer and guaiacol in repeatability study was within 2.7% and in intermediate precision Carfilzomib study was within 0.5%, which confirms the good precision of the method. The % RSD values are presented in Table 2.