Investigation of tropicamide and benzalkonium chloride stability using liquid chromatography

Abstract

In this study, a development of stability indicating method (SIM) that could be used to detect a decrease in the amount of tropicamide and benzalkonium chloride due to their degradation is described. In the method development, stress samples should be used. Benzalkanium chloride proved to be very stable under all stress conditions. Acid stress with 0.1 M HCl C led to 10% degradation of tropicamide alter >= 30 min. The alkaline stress with 1 M NaOH at 70 degrees C induced faster degradation and more than 20% of tropicamide degraded after 30 mm. On the other hand, tropicamide proved to be exceptionally stable to oxidative stress and no degradation was observed with 30% H2O2 even alter heating at 70 degrees C for 90 min. The mobile phase consisted of acetonitrile and water phase 70:30v/v (water phase: 5 mM sodium heptan sulphonate and 1% triethylamine MA) with phi of the mobile phase adjusted to 3.5 with ortophosphoric acid. The flaw rate was 2 mL min(-1). In order to confirm the method adequacy for intended purpose, the proposed method was validated. Finally, the proper validation of developed SIM performed according to the official guidelines proved that the method accomplishes its intended purpose.