Effect of water matrices on removal of veterinary pharmaceuticals by nanofiltration and reverse osmosis membranes

This study explored the removal of five veterinary pharmaceuticals （VPs） （sulfamethoxazole （SMETOX）, trimethoprim （TMP）, ciprofloxacin （CIPRO）, dexamethasone （DEXA） and febantel （FEBA）） from different water matrices （Milli-Q water, model water, tap water and real pharmaceutical wastewater using four types of nanofiltration （NF） membranes （NF90, NF270, NF and HL） and two reverse osmosis （RO） membranes （LFC-1 and XLE）. All VPs were added to different water matrices at a concentration of 10 mg/L. Rejections of VPs and water flux were measured. The rejection increased with increase of molecular weight. The highest rejections were obtained with RO membranes （LFC-1, XLE） and tight NF （NF90） membrane. In general, the rejection of VPs was higher in model water and tap water than in Milli-Q water, but the water flux was lower. This was mainly explained by ion adsorption inside the membranes pores. Narrower pore size counteracted the effect of presence of low concentration of natural organic matter （NOM） in tap water. The NOM was assumed to enhance the adsorption of VPs onto membrane surface, increased the size exclusion and electrostatic repulsion also appeared during the transport. Investigated water matrices had influence on water flux decline due to their complexity.

Evaluation of physicochemical properties as supporting information on quality control of raw materials and veterinary pharmaceutical formulations

This study aimed to show that the physicochemical proprieties obtained by Fourier transform infrared spectroscopy （FTIR）, thermogravimetry （TG）, and scanning electronic microscopy （SEM） can be useful tools for evaluating the quality of active pharmaceutical ingredients （APIs） and pharmaceutical products. In addition, a simple, sensitive, and efficient method employing HPLC-DAD was developed for simulta- neous determination of lidocaine （LID）, ciprofloxacin （CFX） and enrofloxacin （EFX） in raw materials and in veterinary pharmaceutical formulations. Compounds were separated using a Gemini Cm （250 mm×4.6 mm, 5μm） Phenomenex column, at a temperature of 25℃, with a mobile phase containing 10 mM of phosphoric acid （pH 3.29）： acetonitrile （85.7：14.3, v/v） and a flow rate of 1.5 mL/min. Physicochemical characterization by TG, FTIR, and SEM of raw materials of LID, CFX, and EFX provided information useful for the evaluation, differentiation, and qualification of raw materials. Finally, the HPLC method was proved to be useful for evaluation of raw material and finished products, besides satisfying the need for an analytical method that allows simultaneous determination of EFX, CFX, and LID, which can also be extended to other matrices and applications.