A STABILITY-INDICATING HPLC METHOD FOR THE DETERMINATION OF BENZALKONIUM CHLORIDE IN 0.5-PERCENT TRAMADOL OPHTHALMIC SOLUTION

A high-performance liquid chromatographic procedure employing ultravio let detection for the analysis of benzalkonium chloride in 0.5 % Trama dol ophthalmic solution is reported. The method requires minimal sampl e pretreatment and is sensitive, accurate, and reproducible. The peak area versus BAK concentration is linear over the range of 50-150 % of its label claim of 0.05 mg/mL. The mean absolute recovery of BAK using the described method is 100.2 +/- 1.2 %, (mean +/- SD, n = 10). A str ess study with heat, acid, base and UV radiation indicates that the me thod is stability-indicating with no interference from drug or degrada tion products.