Spectrophotometric determination of chloramphenicol-sulphacetamide in eye drops

A rapid method for the determination of chloramphenicol in chloramphenicol-sulphacetamide drops is discussed. The method depends upon precipitating sulphacetamide as its silver salt by a solution of silver nitrate. Chloramphenicol is determined in the filtrate using the modified Vierordt's method. Sulphacetamide was determined by suitably diluting the drops with 0.01 N H2SO4 and then applying the modified Vierordt's method. The presence of macrogols proved not to interfere with the determination. Mean percentage recoveries +/- s.d. for chloramphenicol and sulphacetamide were found to be 100.8 +/- 0.95 and 100.2 +/- 1.0, respectively.