ECO-FRIENDLY GREEN LIQUID CHROMATOGRAPHIC FOR DETERMINATION OF DOXYCYCLINE IN TABLETS AND IN THE PRESENCE OF ITS DEGRADATION PRODUCTS

Doxycycline, an oral antimicrobial, does not present a sustainable analytical method described in the literature using liquid chromatography. A new and efficient method was developed and validated for the quantification of doxycycline tablets by HPLC-UV. Its aim is the contribution to the green analytical chemistry since it has low use of organic solvent and low production of toxic waste. The HPLC-UV method used a mixture of purified water + 0.5 % acetic acid and ethanol (40:60, v/v). The flow rate was 0.8 mL min-1, C18 Luna column, 20 μL of injected volumes at 275 nm. The samples were prepared in purified water and the method was linear over the concentration range of 20–200 μg mL-1 (r = 0.9997) with limits of detection and quantification of 1.08 and 3.27 μg mL-1, respectively. The precision of the method showed RSD 0.50 % (intra-assay), 2.35 % (inter-assay) and 1.13 % (between analysts). The accuracy of the method was determined by standard recovery and it was 99.85 %. The DOX tablets were subjected to oxidative, acid, basic, neutral and photolytic degradation and it showed be stability indicative. Statistical analysis provided reliable, safety and reproducible results. The method is considered linear, selective, precise, accurate, robust, indicative of stability and safe to be used in routine quality control analyzes for determination and quantification of doxycycline in tablets. The proposed method is an ecologically correct alternative for the evaluation of doxycycline tablets.