doiSerbia

Influence of the structure of ceftazidime on obtaining biologically active cellulosic bandage

Rodić-Grabovac Branka B. (University of Banja Luka, Faculty of Technology, Banja Luka, Republic of Srpska, Bosnia and Hercegovina)
Đuđić Radana M. (University of Banja Luka, Faculty of Technology, Banja Luka, Republic of Srpska, Bosnia and Hercegovina)
Sailović Pero S. (University of Banja Luka, Faculty of Technology, Banja Luka, Republic of Srpska, Bosnia and Hercegovina)

Biologically active fibers as drug carriers have improved characteristics in comparison with conventional medical therapies. Cellulosic fibers as hydrophilic and biocompatible, nontoxic and eco-friendly make a good polymer matrix for obtaining biologically active fibers. Current investigations in this area show that the features of these fibers depend on the type of carrier as well as the drug structure. Loading drugs on the fiber carrier is accomplished by ionic bonding between ionized drugs and the groups fixed on the fiber (by ion exchange) or loosely adsorption on the fiber through hydrophobic interactions. These interactions can be achieved between hydrophobic parts of the drug and the fiber carrier or among the hydrophobic drugs bonded on the fiber. Prevailing mechanism of ionized drug bonding on the carrier is ionic, although different hydrophobic interactions can contribute the drug loading to varying degrees. In this paper oxidized cellulose (OC) with different carboxylic group content is obtained by selective oxidation and used for chemical bonding of antibiotic ceftazidime. In its structure this antibiotic has aminothiazole ring and pyridine ring in the side chains of cephem nucleus. Ceftazidime has two carboxylic groups and also great number of electron donors and acceptors. Due to these groups and structures ceftazidime is able to form multiple chemical bonds i. e. interactions with oxidized cellulosic bandage. The bonding was performed in antibiotic water solution concentration of c=3,4∙10-3 mol/L at room temperature (22 ± 1°C), while desorption was performed in physiological solution. The amounts of bonded and released antibiotic were determined spectrophotometrically in UV range. Maximum amount of bound drug (0,0243 mg/g) was obtained during the sorption on the oxidized bandage with 2,276 mmol/g COOH and the maximum amount of released drug was 0,0238 mmol/g. Antimicrobial activity of the samples with bonded ceftazidime was tested in vitro against Staphylococcus aureus, Bacillus subtilis i Escherichia coli by agar diffusion test. The bigest zone of inhibition was obtained for Escherichia. The paper studies the influence of ceftazidime chemical structure, pH of solution in which sorption is performed and sorption duration, on the amount of bonded drug. It was established that the drug bonding was achieved by ionic bonds and the hydrogen bonds of the drug functional groups with oxidised cellulose bandage. Also it was found that buffering of the drug solution, in which bonding is performed, can increase the amount of ceftazidime bonded on the fiber.

Keywords: oxidized cellulose, ceftazidime, biologically active materials