Polymeric-Calcium Phosphate Cement Composites-Material Properties:In VitroandIn VivoInvestigations

Abstract

New polymeric calcium phosphate cement composites (CPCs) were developed. Cement powder consisting of 60 wt% tetracalcium phosphate, 30 wt% dicalcium phosphate dihydrate, and 10 wt% tricalcium phosphate was combined with either 35% w/w poly methyl vinyl ether maleic acid or polyacrylic acid to obtain CPC-1 and CPC-2. The setting time and compressive and diametral tensile strength of the CPCs were evaluated and compared with that of a commercial hydroxyapatite cement. In vitro cytotoxicity and in vivo biocompatibility of the two CPCs and hydroxyapatite cement were assessed. The setting time of the cements was 5–15 min. CPC-1 and CPC-2 showed significantly higher compressive and diametral strength values compared to hydroxyapatite cement. CPC-1 and CPC-2 were equivalent to Teflon controls after 1 week. CPC-1, CPC-2, and hydroxyapatite cement elicited a moderate to intense inflammatory reaction at 7 days which decreased over time. CPC-1 and CPC-2 show promise for orthopedic applications.

Polymeric additives to enhance the functional properties of calcium phosphate cements

“…94 In general, lower cytotoxicity is achieved when CPCs are combined with PAA and derivatives compared to the acrylic bone cements. 140 Composite CPCs have proven in vivo tissue compatibility, suggesting possible clinical applications.…”

Influence of polymer addition on the mechanical properties of a premixed calcium phosphate cement

“…19 Similarly, other systems have shown optimums, both for systems containing polymeric additives as well as for systems reinforced with fibers. 9,22 Although these cements were not as strong as the previously mentioned cements prepared with water and PAA, [8][9][10] there are two big advantages with this type of cement. First, the polymer is both nontoxic and degradable, and second, by utilizing the premixed system, the drawbacks of water-mixed cements, as earlier described, can be avoided.…”

“…Most research has been performed on the incorporation of poly(acrylic acid) (PAA) into the CPC, [8][9][10] giving CPCs with compressive strengths (CS) of up to 90 MPa and diametral tensile strengths (DTS) of up to 21 MPa, which is about a 10-fold increase compared with the plain cements. Although these cements show high mechanical properties they are not optimal due to the poor resorption properties of PAA, and these CPC's can thus mostly be used as models for other composite combinations.…”

Calcium phosphate ceramics in drug delivery

“…CPC composites with polymers, chitosan and gelatin have also been studied. [41][42][43][44] The deleterious effects of organic additives, delayed setting time and decreased mechanical strength, are reported by Ginebra et al 30 It has also been shown that incorporation of alendronate into CPC delays the transformation rate of α-TCP to CDHA, and a decrease in mechanical strength of the CPC due to increase in the drug concentration. 45 Incorporation of stem cells (SC), such as human bone marrow-derived mesenchymal stem cells (hBMMSC) into CPC has also been investigated.…”