0 min, 2.5 min, and 2.6 min, respectively [Figure 5]. As it is evident from Figure 5, the peak area values of all main degradation products were growing in time. Besides the peaks of these degradation products, other small peaks were also found in the exposed samples, but none of them had the area value greater than 1% of concentration of SRT. Furthermore, the amount of these degradation products did not grow markedly during the time of the experiment. Figure 5 Chromatogram of SRT decomposition at 360 min in alkali hydrolysis condition The degradation of SRT in the solution of 3% H2O2 resulted in the formation of two major peaks [Figure 6]. The retention times indicated the agreement of oxidative degradation products with acid ones, but however, the decline of concentration of SRT was much higher than concentration fall in acid hydrolysis. As it is evident, acid, neutral, and oxidative hydrolysis led to the formation of the same degradation products. Figure 6 Chromatogram of SRT decomposition at 360 min in oxidative hydrolysis condition Degradation behavior The susceptibility of SRT to hydrolytic decomposition was determined as a fall of concentration of drug during the time of the experiment. The kinetic slopes are shown in Figure 7. The straight-line behavior was obtained for neutral, alkaline, and oxidative conditions with correlation coefficients R = 0.999, R = 0.998 and R = 0.996, respectively. This fact implies that the hydrolytic degradation followed pseudo-first-order kinetic behaviour. The correlation coefficient for acid hydrolysis was calculated to be R = 0.942. The rate constants were determined from the slope of kinetic curves and their values are: 4.85 �� 10�C2/min (acid condition), 3.40 �� 10�C2/min (neutral condition), 4.32 �� 10�C2/min (alkaline condition), and 8.35 �� 10�C2/min (oxidative condition). The values of rate constants determined that the susceptibility of SRT to hydrolytic decomposition increased in the following manner: Neutral condition < alkaline condition < acidic condition < oxidative condition. Figure 7 Kinetic curves of SRT decomposition CONCLUSION HPLC methods were developed and validated for the estimation of SRT in the presence of its degradation products. LOD and LOQ reported by this method are comparable to the reported one in previous literatures. The most striking feature of the developed method is its simplicity, accuracy, and rapidity. The behavior of SRT under the hydrolytic stress conditions in acid, neutral, alkaline, and oxidative media was studied. The information presented herein could be very useful for quality monitoring of bulk substance as well as the pharmaceutical preparation. ACKNOWLEDGMENT One of the authors, Md. A. Rahman, is highly grateful to the University Grant Commission (UGC), Government of India, for providing financial assistance in the form of Maulana Azad National Fellowship (MANF).