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.