Determination of Spiramycin and Oxytetracycline in binary mixtures by novel spectrophotometric methods with and without regression equation

Abstract

Spiramycin (SPI) and oxytetracycline (OTC) are widely used antibacterial drugs. Thus, a great attention has been focusing on the development of a simple and selective analytical procedure for fast analysis of these compounds in a binary pharmaceutical mixture. Herein, we report four simple and reproducible spectrophotometric methods for determination of SPI and OTC in a binary mixture and in veterinary pharmaceutical formulations. A ratio difference (RD) based on the difference in the amplitude of the ratio spectra and dual wavelength methods were proposed for sensitive and selective determination of SPI in presence of OTC. Furthermore, Constant Value and Concentration Value based spectrophotometric methods were suggested for simultaneous determination of SPI and OTC in a binary mixture. The methods were successfully applied for the determination of SPI and OTC over the concentration range from 4.0 to 36.0 µg mL -1 and from 2.0 to 32.0 µg mL -1 , respectively. The proposed methods were validated according to the International Conference on Harmonization (ICH) guidelines. The methods are accurate (100±1%), precise (%RSD ≤1.5) and cost-effective for determination of SPI and OTC in binary mixtures.