In this stability-indicating, reversed-phase high-performance liquid chromatographic method for flupiritine maleate, forced degradation has been employed and the formed degradants were separated on a C18 column with a 80:20% v/v mixture of methanol-water containing 0. interday precision were below 1.5%. The specificity of the method is suitable for the stability-indicating assay. TEA (pH-adjusted to 3.0 with OPA) and methanol in the ratio of 20:80% was optimized. The circulation rate was 1.0 mLmin?1. The injection volume was 20 L and 874286-84-7 the PDA detection wavelength was at 254 nm. The chromatogram obtained in the optimized condition is usually shown in Fig. 2. It was observed that eight degradation products were created with retention occasions 3.9 0.2 min (D1), 4.8 0.2 min (D2), 6.4 Mmp10 0.1 min (D3), 6.8 0.2 min (D4), 8.2 0.2 min(D5), 12.0 0.2 min (D6), 14.1 0.1 min (D7), and 15.0 0.1 min (D8), respectively. The chromatographic resolution among all of the peaks was more than 2. The % degradation was about 5C30% depending on stress conditions. Fig. 2 Optimized chromatogram of flupirtine maleate (10.3 min) on a C18 column Validation Parameters The method was validated as per ICH (Q2) guidelines with respect to linearity, accuracy, precision, specificity, robustness, limit of detection, and limit of quantification . Answer State Stability The solution state stability of FLU was performed in both water and mobile phases. FLU was estimated every day and carried out for a period of one week. It was concluded that FLU was stable in water for up to 7 days and stable for a period of 3 days in mobile phase. Specificity Forced degradation studies were performed on FLU to support the specificity of the stability-indicating method. The study was employed around the degradation of FLU by acidic hydrolysis (1 M HCl, 24 h), basic hydrolysis (0.01 M NaOH, 3 h), water hydrolysis (7 days), oxidation (0.3% H2O2, 24 h), UV light exposure (48 h), and warmth (105C, 24 h). The method was proven to be specific by separating the degradation products formed under the stress conditions. Linearity and Range The linearity of the detector response to different concentrations of FLU was analyzed in the range to 20C120 gmL?1 at six different concentrations. Samples were analyzed in triplicate at six different concentrations, such as 20, 40, 60, 80, 100, and 120 gmL?1. The correlation coefficient (value) obtained was 0.9998, indicating a linear response of flupiritine maleate. Accuracy Accuracy was determined by recovery studies using standard addition. Standard drugs in the range of 80, 100, and 120% of the sample concentration were added to the sample solution. Each concentration was analyzed in triplicate. Results of the recovery studies were between 99.8 to 101.83% and results are shown in Table 1. Tab. 1 Accuracy of the method (n = 6) Precision Results from the study of intraday and interday precision were obtained by analysis of multiples of the same concentration (50 gmL?1) in the linearity range. The peak area response of each injection was used to calculate the amount of FLU, and the % RSD values for intraday and interday precision were based on the mean and standard deviations. The result was less than 2%, indicating 874286-84-7 that the method was sufficiently precise; results are shown in Table 2. Tab. 2 Intraday and Interday precision of the method Robustness The robustness of the method was determined by the analysis of samples under a variety of changed method conditions, such as flow rate ( 0.1 mL), organic solvent in the mobile phase ( 2%), and pH ( 0.2). The method was strong for all of the conditions for any robust run. The % RSD value for the assay was less than 2% for all of the robust tests. But it was noted that this retention time of FLU was significantly affected ( 1 874286-84-7 min) during the change in % organic phase, however the % RSD value was within the limit. Limit of.