Daina Vempere

Controlled release of local anesthetic from calcium phosphate bone cements.

Novel lidocaine containing calcium phosphate bone cements have been developed. Lidocaine release kinetics of these cements have been evaluated. Calcium phosphate cements have a great potential for local drug delivery. Release of local anesthetic, such as lidocaine, at the implant site can be useful for reducing pain immediately after implantation. In this work a local anesthetic - lidocaine hydrochloride - was incorporated into α-tricalcium phosphate cement. Lidocaine release profile was dependent on cement components used. All cements were characterized by an initial burst release, which can be correlated with cement pH values, followed by gradual drug release. Drug release continued for up to 6 days and was slower, if cement pH was higher. Addition of lidocaine hydrochloride accelerated setting and changed microstructure of the set cement.

The Effect of Pore Forming Agent Particle Size on the Porosity, Microstructure and In Vitro Studies of Hydroxyapatite Ceramics

In situ viscous mass foaming with ammonium bicarbonate (NH4HCO3)as foaming agent was used for the preparation of porous hydroxyapatite ceramics. Three different particle fractions (100-300 μm, 300-500 μm, 500-1000 μm) of NH4HCO3 were used in order to evaluate the particle size effect on the ceramic microstructure. Foamed and dried green bodies were sintered at 1150°C. The porosity and microstructure of ceramics were determined with Archimedes method and scanning electron microscopy. As the NH4HCO3 particle fraction was decrease from 100-300 μm to 500-1000 μm, the open porosity increased from 42 to 54 %. In situ viscous mass foaming leads to the interconnected pore channels with wide pore size range (10-600 μm). In the present work cytotoxicity of obtained porous HA ceramics and fibroblast cell viability was investigated.