THE HYDROXAMIC REACTION IN THE ANALYSIS OF 2-ACETOXYBENZOIC ACID AND OF N-(4-HYDROXYPHENYL) ACETAMIDE

The study of the conditions of hydroxamate reaction depending on the pH for the acid 2 –acetoxybenzoic and N-(4-hydroxyphenyl) acetamide, simultaneously included in the composition of the tablets «Askofen-P» and «Citramon-P». Materials and methods. We used pharmaceutical substances of acetylsalicylic acid and paracetamol, which meet the requirements of the corre-sponding pharmacopoeial articles. When performing the experiments, solvents and reagents with the “pure for analysis” qualification were used. A proce-dure for analyzing acetylsalicylic acid and three variants of the method for analyzing paracetamol (at different pH) are presented. Results and discussion. As a result of the study was found that for 2-acetoxybenzoic acid we observed copper hydroxamate in the form of green solution, later a green sediment fell out, iron hydroxamate - in the form of red solution. In the case of decreasing of pH range till 4 the visible effect wasn't distinguished from the previous colours. For N-(4-hydroxyphenyl) acetamide (paracetamol) we observed the copper hydroxamate in the form of green sediment moving to a bright blue solution, with the solution of iron (III) chloride - an orange-red solution. Conclusions. The hydroxamic reaction for 2-acetoxybenzoic acid with copper and iron (III) salts passes in slightly basic, neutral and slightly acidic medium. The forming of copper hydroxamate in the case of N-4-hydroxyphenyl acetamide passes in the range of рН from 7 to рН=5. The forming of iron (III) hydroxamate passes in the range of рН from 5 to рН=2.