The aim of this work is the synthesis of calcium carbonate (CaCO3) nano and microparticles and their application as biomaterials (vehicles) for the sustained release of doxycycline. CaCO3 micro particles were synthesized by water-in oil (W/O) emulsion method using emulsion liquid membranes with bis (2-ethylhexyl) phosphate (D2EHPA) as carrier, Span 80 as surfactant, and toluene and kerosene as organic solvents. The aqueous phases contained 1 M CaCl2, and 1 M Na2CO3, respectively. The Dynamic Light Scattering (DLS) data showed CaCO3 particles with sizes ranging from around 100 nm to 3500 nm. The CaCO3 particles with the average diameters around 600 nm attained an adsorbtion of doxycycline of maximum 97.9%, and a slow and steady release with a cumulative value of approximative 50% after ten days.

Polystyrene latex particles were prepared by using an emulsifier-free emulsion polymerization with two ionic initiators: potassium persulfate (KPS) and 2,2’-azobis(2-amidinopropane)dihydrochloride (AIBA). The purpose of this study was to obtain polystyrene latex with a good stability in time, a high surface charge density and a small particle size (between 100 and 1000 nm). We used two distinctive molar concentrations for both initiators: 5.5 mM and 55 mM based on aqueous phase. The analysis showed that in the case of KPS initiator the latexes stability was better. With AIBA as initiator smaller latex particles can be achieved. A high surface charge density was measured for large initiator concentration. We achieved satisfying results with both initiators, the optimal condition of polymerization depending on the subsequent utilization of the latex. The SEM images showed that latexes containing bentonite and latexes with no clay have similar size.

The hydroxyapatite (HA) nano and microparticles were synthesized by wet-chemical precipitation in order to use them as drug carriers for biomedical applications. Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS) and Fourier Transform Infrared Spectroscopy (FTIR) were performed to assess their size, external morphology and chemical composition. The properties of HA particles as drug carriers for antibiotics delivery were evaluated with doxycycline and chloramphenicol. The amount of drug loading and release was determined by UV-Visible spectrophotometry. The antibacterial properties of loaded HA particles were evaluated using gram-positive Bacillus subtilis bacteria and gram-negative Pseudomonas aeruginosa bacteria. The synthesized particles of HA exhibit a high adsorption capacity (around 99%) and good controlled release properties for doxycycline. The adsorption of chloramphenicol on HA was extremely low (about 2%). According to the results, the compatibility between the drug and substrate is an important factor in the absorption process, and the hydroxyapatite is a very promising carrier for controlled release of antibiotics.