Biphasic Resorbable Calcium Phosphate Ceramic for Bone Implants and Local Alendronate Delivery

Abstract

A novel biphasic calcium phosphate ceramic composed of tricalcium phosphate (TCP) and calcium pyrophosphate (CP) is synthesized in order to tailor the biodegradation behavior of the ceramic. The results show that biphasic TCP/CP ceramic has a strength of 62.2 ± 2.1 MPa, which is superior to single‐phase TCP and CP ceramics, which show strengths of 44.3 ± 3.0 and 53.0 ± 4.8 MPa, respectively. In addition, biphasic TCP/CP ceramic displays a controlled strength degradation from 62.2 ± 2.1 to 40.5 ± 1.0 MPa in stimulated body fluid over a period of 28 d. An in vitro cell materials interaction study using human fetal osteoblast cells indicates that TCP/CP ceramic is cytocompatible. TCP/CP ceramic also show a good loading capacity for alendronate. Adsorption of alendronate (AD) on the TCP/CP surface is found to proceed via ligand exchange mechanism and the in vitro release profile of AD from TCP/CP surface is characterized by an initial fast release followed by a slow and sustained release. Strong electrostatic interactions between AD groups and surface Ca2+ ions enable the slow and sustained release of AD. These results demonstrate that the newly developed biphasic ceramic, with its controlled strength degradation and drug release, shows promise for use in orthopedic and tissue engineering applications.

ZnO, SiO2, and SrO doping in resorbable tricalcium phosphates: Influence on strength degradation, mechanical properties, and in vitro bone–cell material interactions

“…β‐TCP has been shown to have excellent biocompatibility, osteoconductivity, and time‐dependent biodegradation characteristics 1, 3. In many applications, the time‐dependent biodegradation properties makes β‐TCP an ideal scaffold material for bone tissue engineering, where the ceramic temporarily supports bone in‐growth, while eventually being replaced by natural tissue 4–6. The use of such bone substitute reduces the need for a possible second site surgery that is often needed for autograft harvesting 1.…”

“…1,3 In many applications, the time-dependent biodegradation properties makes b-TCP an ideal scaffold material for bone tissue engineering, where the ceramic temporarily supports bone in-growth, while eventually being replaced by natural tissue. [4][5][6] The use of such bone substitute reduces the need for a possible second site surgery that is often needed for autograft harvesting. 1 However, the in vivo strength degradation profile of pure b-TCP is not ideal for many applications in which controlled strength loss is necessary over a specific period.…”

Effect of electrical polarization and composition of biphasic calcium phosphates on early stage osteoblast interactions

“…Calcium phosphates (CaPs) are widely used in bone‐tissue engineering due to their excellent bioactivity and compositional similarities to bone 1–3. Among various calcium phosphates, hydroxyapatite [HAp, Ca 10 (PO 4 ) 6 (OH) 2 ] and β‐tricalcium phosphate [β‐TCP, Ca 3 (PO 4 ) 2 ] are most commonly used because of their osteogenic property and the ability to form strong bonds with host bone tissues.…”

Characterization and dissolution–reprecipitation behavior of biphasic tricalcium phosphate powders

“…Recently, it has been found that biphasic Ca phosphate is a good way to make full use of the advantages from each monophasic Ca phosphate for enhancing performances in applications [15][16][17][18].…”