Studies on Quality of Pharmaceutical Preparations. III. : Determination of Naphazoline and Other Components in Drugs by Gas Chromatography

Abstract

Naphazoline contained in mixed eye-lotion was converted into N-acetyl and N-butyryl derivatives and determined by gas chromatography supported on 1.5% OV-17 along with chlorpheniramine maleate and T-caine, the consituents commonly present. The amount of sample corresponding to about 10 mg of naphazoline was taken, made alkaline with ammonia, and extracted with chloroform or carbon tetrachloride. The extract was dehydrated over anhydrous sodium sulfate and evaporated to dryness under reduced pressure below 40°. The residue was dissolved in 4.0 ml of 0.2% dioctyl phthalate solution, when T-caine was not present. To this solution was added 10 μl of acetic anhydride and shaken for 15 min. Excess reagent was decomposed by adding 2 ml of 10% sodium hydrogen carbonate solution. The chloroform layer was separated and dehydrated over anhydrous sodium sulfate, 1.0-2.0 μl of this chloroform solution was injected into gas chromatography. When T-caine was present, the residue was dissolved in 4.0 ml of chloroform solution of 0.2% dicyclohexyl phthalate, added with 20 μl of butyric anhydride, and shaken for 30 min. The excess reagent was decomposed with 2 ml of 10% sodium hydrogen carbonate solution. The chloroform solution was treated and applied to gas chromatography in the same manner as N-acetyl derivative. The decomposed products of naphazoline such as ethylenediamine, 1-naphthylacetic acid, and 1-naphtylacetylethylenediamine did not interfere in this method.