Influence of Peroxide Impurities in Povidone on the Stability of Selected β-Blockers with the Help of HPLC.

A present study was conducted to investigate compatibility of β-blocker drugs( like atenolol, labetalol hydrochloride, bisoprolol fumarate, metoprolol succinate, carvedilol and propranolol hydrochloride) with the pharmaceutical excipient povidone. To check the influence of peroxide impurity present in povidone on the stability of β-blockers, a binary mixture technique has been adopted. The binary mixtures (1:1) of β-blockers with povidone excipient were stored for the duration of 6 months at accelerated conditions (40°C and 75% RH) and analyzed with the technique of high-performance liquid chromatography (HPLC). On analysis, HPLC results shows that, the percentage of total impurity for atenolol-2.15%, bisoprolol fumarate-3.55%, carvedilol-2.19%, and labetalol hydrochloride-1.89%, with respect to povidone. To verify the interaction of H2 O2 present in povidone as an impurity, oxidative degradation of selected active pharmaceutical ingredients were performed and degradation profile were compared with that of degradation impurities generated in drug-excipient mixture at accelerated conditions. The relative retention time (RRT) of impurities generated in accelerated stability study samples resembles the RRT of degradation products generated by oxidative degradation of pure drugs. Thus, it confirms that degradation of β-blockers with povidone was mediated by organic peroxides present as an impurity in povidone.