Antibiotic and anesthetic drug release from double-setting α-TCP cements

The alpha phase of tricalcium phosphate (α-TCP) can form calcium-deficient hydroxyapatite (CDHA), similar to bone hydroxyapatite. α-TCP can be employed as a biocompatible cement and used as a drug vehicle. Double-setting α-TCP cement composed of acrylamide (α-TCP DS) has better mechanical properties than traditional α-TCP cement. However, no studies on the use of α-TCP DS-based systems for drug release have been reported. In this study, we prepared α-TCP- and α-TCP DS-based samples containing gentamicin sulfate, lidocaine hydrochloride, bupivacaine hydrochloride and levobupivacaine hydrochloride. The properties of the samples were characterized, and the use of the samples as vehicles for these drugs was evaluated. The cements were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, mechanical property tests and apparent porosity evaluation. The drug release in vitro was determined using ultraviolet–visible absorption spectroscopy. For statistical analysis, a confidence interval of 95% with a significance level < 5% was used. Neither the hydrogel nor the drugs interfered with the formation of CDHA, but they increased the mechanical strength of the studied cement. The Peppas–Sahlin model described the mechanisms involved in the drug-release kinetics process, revealing that Fickian diffusion was the main drug-release mechanism with a small influence from the Case II mechanism.