Physicochemical and microbiological properties of eye drops containing cefuroxime.

The purpose of the studies was to examine the influence of the additives and storage temperature on physicochemical properties and on the antimicrobial activity of cefuroxime in the eye drops. The eye drops were 1% sterile aqueous solutions of cefuroxime in citrate buffer of pH 6.15-6.20, preserved with 0.002% thiomersal or 0.001% phenylmercuric borate with 0.4% beta-phenylethyl alcohol. Viscosity of the eye drops was increased using polyvinyl alcohol. The drops, protected from light, were stored at the temperature of 4 degrees C and 20 degrees C. As the criteria of the qualitative assessment of freshly prepared eye drops and during their storage, the following properties were considered: organoleptic analysis (color, clarity, and smell), sterility, pH, osmotic pressure, density, and viscosity, antimicrobial activity of cefuroxime and preservation efficiency of thiomersal and phenylmercuric borate in the eye drops. The storage temperature had a significant influence on the antimicrobial activity of the antibiotic in the eye drops. The antimicrobial activity of cefuroxime in the drops stored for 30 days at the temperature of 4 degrees C did not decrease. Thiomersal at the concentration over 0.003%, 0.005% benzalkonium chloride and 0.01% chlorhexidine diacetate were not compatible with cefuroxime in the drops.