Kostiv O. Azo coupling reaction in the analysis of β-lactam and tetracycline antibiotics

The thesis is devoted to the research of spectrophotometric and voltammetric properties of azo compounds obtained from β-lactam and tetracycline antibiotics. To develop the methods of investigated antibiotics determination two different ways of azo coupling reaction were used: between amoxicillin, oxytetracycline and diazotized reagents containing in their structure a primary aromatic amino group, as well as between diazotized cephalosporins and phenolic reagents. The possibilities of using the obtained azo compounds for quantitation of amoxicillin, ceftazidime, ceftriaxone and oxytetracycline were studied. Relies on the research of chemical and analytical properties of antibiotics such azo coupling reactions were used for the first time: amoxicillin with diazotized sulphathiazole or with sulphanilamide; oxytetracycline with 1-diazo-2-naphthol-4-sulfonic acid or with diazotized fuchsine; diazotized ceftazidime with resorcinol, or with 8-oxyquinoline, or with 2-methylphenol; diazotized ceftriaxone with 8-oxyquinoline, or with 2-methylphenol. All reactions were used for the development of methods for spectrophotometric determination of antibiotics in single- and multicomponent drugs. For the first time, the optimal conditions for diazotization of reagents for further azo coupling with amoxicillin and oxytetracycline, and for diazotization of cephalosporin antibiotics for further interaction with with resorcinol, 8-oxyquinoline, 2-methylphenol were investigated. Among them were acid nature and concentration (as diazotizing medium), excess of the diazotizing reagent (sodium nitrite) and duration of diazotizing. For the first time, the optimal conditions for azo coupling of 1-diazo-2-naphthol-4-sulfonic acid, fuchsine, sulphathiazole and sulphanilamide diazo salts with antibiotic, and cephalosporin antibiotic diazo salts with phenolic reagents were studied, in particular, acidity of the interaction medium, reagent excess, influence of foreign electrolytes to obtain the maximum analytical signal. That allowed to obtain effective color analytical forms of antibiotics with reagents and develop methods for quantitation of these antibiotic.