PHOSPHOCALCIC CEMENT COMPOSITION COMPRISING BLOOD

Abstract

A bone cement paste containing a powder component comprising α-tricalcium phosphate (α-TCP) particles having an average size greater than or equal to 9 μm, and a liquid component comprising blood is disclosed. A method for preparation of the phosphocalcic cement composition is also disclosed.

Claims

1. A bone cement paste comprising a powder component and a liquid component comprising blood; wherein the powder component comprises, in relation to the total weight of the powder component: at least 70% by weight of α-tricalcium phosphate (α-TCP) particles having an average size greater than or equal to 9 μm, wherein said average size is the mean equivalent diameter of said particles measured by LASER diffraction analysis; and at least 5% by weight of calcium-deficient apatite (CDA); wherein the liquid component (L)/powder component (P) ratio is between 0.3 and 0.7 mL/g; and wherein the bone cement paste has a setting time ranging from 10 minutes to 72 hours.

2. The bone cement paste according to claim 1, wherein the liquid component is blood.

3. The bone cement paste according to claim 1, wherein the α-tricalcium phosphate (α-TCP) particles have an average size greater than or equal to 10 μm.

4. The bone cement paste according to claim 1, wherein the powder component further comprises at least one calcium phosphate compound selected from the group consisting of hydroxyapatite (HA), amorphous calcium phosphate (ACP), monocalcium phosphate anhydrous (MCPA), monocalcium phosphate monohydrate (MCPM), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate anhydrous (DCPA), β-tricalcium phosphate (β-TCP), tetracalcium phosphate (TTCP), and mixtures thereof.

5. The bone cement paste according to claim 4, wherein the calcium phosphate compound is dicalcium phosphate anhydrous (DCPA).

6. The bone cement paste according to claim 5, wherein the powder component comprises at least 1% by weight of DCPA, in relation to the total weight of the powder component.

7. The bone cement paste according to claim 1, wherein the powder component further comprises at least one cellulose ester.

8. The bone cement paste according to claim 7, wherein the cellulose ester is selected from the group consisting of hydroxypropylmethylcellulose (HPMC) and carboxymethylcellulose (CMC).

9. The bone cement paste according to claim 7, wherein the powder component comprises between 0.1% and 5% by weight of the cellulose ester, in relation to the total weight of the powder component.

10. The bone cement paste according to claim 1, wherein the liquid component (L)/powder component (P) ratio is between 0.4 and 0.6 mug.

11. The bone cement paste according to claim 10, wherein the liquid component (L)/powder component (P) ratio is 0.45 or 0.55 mL/g.

12. An apatitic calcium phosphate cement resulting from the setting of the bone cement paste according to claim 1, wherein the apatitic calcium phosphate cement has a compressive strength between 2 MPa and 15 MPa.

13. The apatitic calcium phosphate cement of claim 12, further including a contrasting agent for X-ray imaging or MRI, and/or further including a therapeutic agent or a compound that will present a therapeutic effect.

14. The apatitic calcium phosphate cement of claim 12, wherein the α-tricalcium phosphate (α-TCP) particles have an average size greater than or equal to 10 μm.

15. An apatitic calcium phosphate cement obtainable by a process comprising the following steps: the preparation of a bone cement paste by mixing a powder component and a liquid component comprising blood, and wherein the powder component comprises, in relation to the total weight of the powder component: at least 70% by weight of α-tricalcium phosphate (α-TCP) particles having an average size greater than or equal to 9 μm, wherein said average size is the mean equivalent diameter of said particles measured by LASER diffraction analysis; and at least 5% by weight of calcium-deficient apatite (CDA); wherein the liquid component (L)/powder component (P) ratio is between 0.3 and 0.7 mL/g; and wherein the bone cement paste has a setting time ranging from 10 minutes to 72 hours; and the setting of said bone cement paste; wherein the apatitic calcium phosphate cement has a compressive strength between 2 MPa and 15 MPa.

16. The apatitic calcium phosphate cement of claim 15, wherein the α-tricalcium phosphate (α-TCP) particles have an average size greater than or equal to 10 μm.

17. A method for filling a dental or bony defect, comprising injecting the apatitic calcium phosphate cement according to claim 12 into said defect.

18. An implant comprising the apatitic calcium phosphate cement according to claim 12.

19. A method for promoting spine fusion inside intersomatic cages, comprising: placing a fusion cage between two vertebral bodies, and injecting the bone cement paste according to claim 1 inside the fusion cage.

20. A kit for spinal fusion, comprising: a fusion cage, and a bone cement paste according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0134] FIG. 1: Variation of dielectric permittivity, ε′ (left), and dielectric losses, ε″ (right) versus reaction time for (A) QS cement alone (a) and its blood-containing analogue (b); (B) HBS cement alone (c) and its blood-containing analogue (d). Frequency: 10 MHz, temperature: 37° C. FIG. 1A contains comparative data and FIG. 1B compares the composition according to the invention (with blood) with a composition without blood.

[0135] FIG. 2: Force necessary for extrusion of the cement paste as a function of time at 20° C. for QS (Δ)(comparative composition) and its blood-containing analogue (comparative composition)(.box-tangle-solidup.), HBS (□)(comparative composition) and its blood-containing analogue (.square-solid.)(composition according to the invention).

[0136] FIG. 3: Compressive strength of the cement formulations after a setting time of 72 hours: (right) QS (straight line) and its blood-containing analogue (dotted line), (left) HBS (straight line) and its blood-containing analogue (dotted line).

[0137] FIG. 4: Comparative quantitative analysis of newly formed bone and remaining implanted materials from SEM measurements.

[0138] FIG. 5: SEM micrographs of comparative composition (a), composition according to the invention (b), and autograft (c).

[0139] FIG. 6: 3D quantifications inside cage volumes (500 mm.sup.3—μCT analysis—resolution 12 μm).

EXAMPLES

[0140] Materials

[0141] The apatitic calcium phosphate cements (CPC) used in this study were obtained from Graftys SA (Aix-en-Provence, France).

[0142] Graftys® HBS

[0143] Graftys® HBS is a mixture of 78 wt. % α-tricalcium phosphate (α-TCP) (Ca.sub.3(PO.sub.4).sub.2)(average equivalent diameter: 12 μm), 5 wt. % dicalcium phosphate dihydrate (DCPD) (CaHPO.sub.4, 2H.sub.2O), 5 wt. % monocalcium phosphate monohydrate (MCPM) (Ca(H.sub.2PO.sub.4).sub.2, H.sub.2O), 10 wt. % CDA (Ca.sub.10-x[ ].sub.x(HPO.sub.4)y(PO.sub.4).sub.6-y(OH).sub.2-z[ ].sub.z), 2 wt. % hydroxypropyl methyl cellulose (HPMC) (E4 M®, Colorcon-Dow Chemical, Bougival, France).

[0144] The liquid phase consists of a 5 wt. % Na.sub.2HPO.sub.4 aqueous solution (liquid/powder ratio=0.5 mL.Math.g.sup.−1).

[0145] Graftys® Quickset

[0146] Graftys® Quickset is a mixture of 78 wt. % α-TCP (average equivalent diameter: 5 μm), 10 wt. % anhydrous dicalcium phosphate (DCPA) (CaHPO.sub.4), 10 wt. % CDA, 2 wt. % HPMC.

[0147] The liquid phase consists of a 0.5 wt. % Na.sub.2HPO.sub.4 aqueous solution (liquid/powder ratio=0.45 mL.Math.g.sup.−1).

[0148] Graftys® HBS and Graftys® Quickset cement paste samples were prepared by mixing 8 g of the powdered preparation with their respective liquid phase for 2 min to ensure the homogeneity of the obtained paste before analysis.

[0149] The same conditions were applied for the preparation of the corresponding blood/CPC composites, except that the liquid phase was fully replaced by ovine freshly harvested blood.

[0150] Methods

[0151] The high frequency impedance measurements were recorded, between 0.4 and 100 MHz, with a HP 4194 A impedance/gain-phase analyser (Hewlett-Packard), using an experimental setup allowing to concomitantly perform complex impedance and Gillmore needles measurements at 37° C., as reported previously (Despas, C.; Schnitzler, V.; Janvier, P.; Fayon, F.; Massiot, D.; Bouler, J. M.; Bujoli, B.; Walcarius, A. High-frequency impedance measurement as a relevant tool for monitoring the apatitic cement setting reaction Acta Biomater 2014, 10, 940).

[0152] The experimental device was completed by a computer allowing automatic data acquisition and real-time calculation of the complex impedance, Z* from which the dielectric permittivity, ε′ (related to dipole variation), and dielectric losses, ε″ (related to the motion of free charges), were computed (Thiebaut, J. M.; Roussy, G.; Chlihi, K.; Bessiere, J. Dielectric study of the activation of blende with cupric ions Journal Of Electroanalytical Chemistry 1989, 262, 131).

[0153] The initial setting time (t.sub.i) is defined as the time elapsed until the small Gillmore needle (diameter 2.12 mm, weight 113.4 g) fails to indent the surface of the sample, while the final setting time (t.sub.f) is the corresponding value when using the large Gillmore needle (diameter 1.06 mm, weight 453.6 g)

[0154] Compressive strength measurements and texture analyses versus time were performed using a AMETEK LS5 texture analyzer. The compression force necessary to extrude the cement paste samples from a syringe (inner diameter of the cartridge 8.2 mm, inner diameter of the exit hole 1.7 mm) was measured versus time at regular intervals (ca. every 3 min), while keeping the extrusion rate constant (0.1 mm s.sup.−1).

[0155] In Vivo Implantation of Graftys® HBS and Graftys® Quickset CPC Versus their Respective Blood Composites

[0156] Animals and Surgical Procedures

[0157] All animal handling and surgical procedures were conducted according to European Community guidelines for the care and use of laboratory animals (DE 86/609/CEE) and approved by the local Veterinary School ethical committee.

[0158] The tested biomaterials have been implanted bilaterally for 4 weeks and 8 weeks respectively at the distal end of 24 mature female New Zealand White rabbit (3-3.5 kg) femurs. A lateral arthrotomy of the knee joint was performed and a cylindrical 6×10 mm osseous critical-sized defect was created at the distal femoral end. After saline irrigation, the osseous cavity was carefully dried and filled with the tested calcium phosphate cements. Twelve rabbits were implanted with Graftys®HBS versus its blood composite, and the same number with Graftys® Quickset versus its blood composite.

[0159] Two-Dimensional Histomorphometric SEM Analysis and Histological Studies

[0160] Implanted and control samples were classically prepared for SEM-based histomorphometry and qualitative histological examination on light microscopy [For details see Gauthier et al. 2005, Biomaterials). Undecalcified serial 7 mm sections of each sample were stained using Movat's pentachrome staining. This bone specific staining is perfectly adapted to distinguish mineral (yellow-green), osteoid tissue (red line) and cement (blue)(Verron, E.; Gauthier, O.; Janvier. P.; Pilet. P.; Lesoeur, J.; Bujoli, B.; Guicheux, J.; Bouler, J. M. In vivo bone augmentation in an osteoporotic environment using bisphosphonate-loaded calcium deficient apatite Biomaterials 2010, 31, 7776). To analyze more specific tissue components, hematoxylin-eosin was performed. Samples were observed with a polarized light microscope (Axioplan2®, Zeiss, Germany).

[0161] Statistical Analysis

[0162] SEM-Based Histomorphometry for the Rabbit Study

[0163] The means for each of the 8 experimental groups (N=6) were calculated and statistical difference between different groups and between different treatments were evaluated by analysis of variance (ANOVA). The threshold for significance was set at 95% (p=0.05).

Example 1: Setting Times of the Compositions

[0164] The setting time of a composition according to the invention was compared with prior art compositions without blood and with a composition with blood and a CPC wherein the α-TCP particles have an average size particle of less than 10 μm.

[0165] Blood was introduced into the composition of two commercially available injectable apatitic cements (Graftys® Quickset [abbreviated as QS] and Graftys® HBS [abbreviated as HBS]) showing marked differences in their setting time (see Table 1). For that purpose, the liquid phase (0.5 wt. % Na.sub.2HPO.sub.4 and 5 wt. % Na.sub.2HPO.sub.4, respectively) was fully replaced by ovine blood stabilized by addition of sodium citrate (3.2 wt. %), while keeping all other parameters fixed.

[0166] The potential influence of blood on the CPC setting reaction at body temperature was first investigated using the Gillmore needles standard test method, which allows determining the initial (t.sub.i) and final (t.sub.f) setting times by measuring the change in the material's penetration resistance. While a 4 minutes increase in the initial setting time was observed upon addition of blood in the fast setting formulation (QS), the Gillmore method failed to determine the t.sub.i value when blood was used as the liquid phase in HBS, since no ‘visible indentation’ could be observed, due to the elastic texture of the resulting composite.

TABLE-US-00001 TABLE 1 Characteristic parameters resuiting from the monitoring of the setting reaction of the studied cements at 37° C., using Gillmore needles (first line) or high frequency impedance (four next lines), as a function of the liquid phase (phosphate buffer versus blood). HBS QS (comparative) 5 wt. % Liquid 0.5 wt. % Na.sub.2HPO.sub.4 Blood phase Na.sub.2HPO.sub.4 blood (comparative) (invention) Gillmore t.sub.1 (min) 7 ± 1 12 ± 2 15 ± 2 not determination measurable HF t.sub.1(e′) (min) <6.sup.a <4.sup.a <4.sup.a 900 impedance t.sub.1(e″) (min) <6.sup.a <4.sup.a <4.sup.a 900 determination t.sub.2(e″) (min)  5 270   40  1100 t.sub.2(e″) (min) 10  550   37  1200 .sup.aCement hardening began before the first measurable dielectric values (see Materials and methods)

[0167] The article of Despas, C.; Schnitzler, V.; Janvier, P.; Fayon, F.; Massiot, D.; Bouler, J. M.; Bujoli, B.; Walcarius. A. High-frequency impedance measurement as a relevant tool for monitoring the apatitic cement setting reaction Acta Biomater 2014, 10, 940 reports the development of a relevant and general method based on high frequency impedance measurements, for the in situ monitoring of the alpha-tricalcium phosphate (α-TCP) to calcium-deficient hydroxyapatite (CDA) transformation which is the driving force of the hardening process of apatitic CPCs.

[0168] From the complex impedance data, the dielectric permittivity (ε′, related to dipole variation) and dielectric losses (ε″, related to the motion of free charges) can be computed. The variation of both of these parameters turned out to be strongly correlated to the chemical reactions taking place during the setting process, in contrast to the Gillmore conventional standard method which shows significant limitations in some cases, especially when additives are present in the cement paste.

[0169] Therefore, the impedance response of QS and HBS, compared to their analogues combined to blood, was recorded and the evolution of the ε′ and ε″ experimental values during the setting reaction are presented in FIG. 1. As shown previously, the sharp variations of the ε′ and ε″ curves (↑ε′ and ↓ε″ values) can be assigned to the conversion of α-TCP into CDA on the particles surface.

[0170] In the case of the fast setting formulation (comparative data with QS), substitution of the liquid phase by blood did not result in a significant change in the evolution of the dielectric permittivity and dielectric losses versus reaction time, although the initiation of CDA precipitation was slightly shifted towards longer times for the blood-containing composition. This is in sharp contrast with the case of HBS for which the setting reaction was drastically retarded (ca. 13 hours) in the presence of blood as the liquid phase (corresponding to a composition according to the invention).

[0171] The results concerning QS are shown in FIG. 1A and the results concerning HBS are shown in FIG. 1B.

Example 2: Injectability of the Compositions

[0172] Texture analyses are relevant to probe the injectability of calcium phosphate pastes and assess their behavior under pressure (Ginebra, M. P.; Rilliard, A.; Fernandez, E.; Elvira, C.; San Roman, J.; Planell, J. A. Mechanical and rheological improvement of a calcium phosphate cement by the addition of a polymeric drug J Biomed Mater Res 2001, 57, 113).

[0173] For both cements without blood, extrusion forces rapidly reach a plateau, followed by a very sharp increase (FIG. 2), which corresponds to the beginning of the hardening process.

[0174] Substitution of the liquid phase by blood led to more injectable materials, especially for the HBS-based composition according to the invention, in full agreement with the variation of setting properties evidenced by impedance measurements (as mentioned in example 1).

[0175] In all cases, the increase in the force necessary for extrusion of the cement paste was not due to phase separation, since the full content of the syringe could be injected.

Example 3: Mechanical Properties of the Compositions

[0176] The introduction of blood into the CPC compositions did not result in significant changes in the mechanical properties of the QS formulation. Indeed, for these comparative compositions, the compressive strength after a setting time of 72 hours was in the similar range in the presence (21±2 MPa) or absence (25±5 MPa) of blood, with a fragile behaviour (see FIG. 3 right). This observation is consistent with the very limited effect of blood on the complex impedance response.

[0177] On the contrary, a dramatic change was observed for the composition according to the invention (HBS formulation), since when combined to blood the compressive strength after a setting time of 72 hours considerably dropped (6.4±0.1 MPa for the composition of the invention versus for the 14±2 MPa for the comparative composition without blood).

[0178] Interestingly, the stiffness was less than HBS, accounting for a more plastic behaviour of the sample (see FIG. 3 left) from 72 hours to 336 hours post mixture.

Example 4: Resorption Properties of the Compositions

[0179] Quantitative SEM Histomorphometry

[0180] Four weeks after implantation (as explained above), all groups showed an equivalent new bone formation and only the compositions according to the invention (HBS/blood) presented a significantly higher material degradation compared to the other groups (p<0.0001) (FIG. 4A). After 12 weeks, the compositions according to the invention (HBS/blood composition) underwent significantly higher material degradation (p<0.0001) and led to higher new bone formation (p<0.01), when compared to the other groups (FIG. 4B).

Example 5: In Vivo Response Comparisons in Ovine Spine Fusion of CPC, CPC Blood Composite and Autograft

[0181] An in vivo study was conducted in sheep to evaluate the capacity of the compositions according to the invention (in comparison with a composition without blood) in promoting spine fusion inside intersomatic cages 3 months after implantation. Autograft was used as positive control.

[0182] Compositions [0183] The comparative CPC is a mixture of 78 wt. % α-TCP, 10 wt. % anhydrous dicalcium phosphate (DCPA) (CaHPO.sub.4), 10 wt. % CDA, 2 wt. % HPMC. Average size of inorganic powder particles was 6 μm. The liquid phase consists of a 0.5 wt. % Na.sub.2HPO.sub.4 aqueous solution (liquid/powder ratio=0.45 mL.Math.g.sup.−1). [0184] The composition of the invention is a mixture of 78 wt. % α-tricalcium phosphate (α-TCP) (Ca.sub.3(PO.sub.4).sub.2), 5 wt. % dicalcium phosphate dihydrate (DCPD) (CaHPO.sub.4, 2H.sub.2O), 5 wt. % monocalcium monohydrate (MCPM) (Ca(H.sub.2PO.sub.4).sub.2, H.sub.2O), 10 wt. % CDA (Ca.sub.10-x[ ].sub.x(HPO.sub.4)y(PO.sub.4).sub.6-y(OH).sub.2-z[ ].sub.z), 2 wt. % hydroxypropyl methyl cellulose (HPMC)(E4 M®, Colorcon-Dow Chemical, Bougival, France). Average size of α-TCP was 12 μm. The liquid phase consists of fresh ovine blood stabilized by addition of sodium citrate (3.2 wt. %) (liquid/powder ratio=0.5 mL.Math.g.sup.−1). [0185] An autologous corticocancellous bone graft was harvested from the distal femoral epiphysis site.

[0186] Intersomatic Cages

[0187] Polyether-ether-ketone cages LDR-ROI-C® (14×14×6 mm) were placed after dissectomy between L2/L3 and L4/L5 ovine intervertebral levels. Autograft was crushed with a rongeur and then packed into the fusion cage before its impaction. The compositions according to the invention and the comparative compositions were injected inside cages after impaction. Three months after implantation, animals were euthanatized by intravenous injection of 20 ml of pentobarbital (Doléthal®, Vétoquinol S.A., France) through a catheter placed into the jugular vein. Lumbar segments from L1 to L5 were then harvested after dissection from the surrounding soft tissues, submitted to XRay imaging and immediately placed in a 10% neutral formol solution. L2/L3 and L4/L5 intervertebral specimen were fixed at 4° C. for 24 h in neutral formol solution, pH 7.2, and then dehydrated in increasing ethanol baths from 70% to 100% for 3 days each. Resin impregnation was then performed by using methylmethacrylate.

[0188] Results

[0189] SEM observation (FIG. 5) and 3D-μCT quantitative analysis (FIG. 6) show that: [0190] Comparison of the composition of the invention with the comparative composition: a strong increased resorption rate and consequently an increased new bone formation at 3 months postoperatively; and [0191] Comparison of the composition of the invention with the autograft: a comparative fusion rate at 3 month postoperatively.

[0192] After 12 weeks of implantation the blood composite cement showed a better resorption rate (+22%) compared to control. Quality of newly formed bone is very similar for both tested CPCs with an excellent bone/implant osteocoalescent interface.

Example 6: Setting Times and Compressive Strength of a Composition According to the Invention

[0193] The setting time of a composition according to the invention was compared with prior art compositions without blood and with a composition with blood.

[0194] The apatitic calcium phosphate cements (CPC) used in this study were obtained from Graftys SA (Aix-en-Provence, France).

[0195] Graftys® GQSb10h is a mixture of 78 wt. % α-TCP (average equivalent diameter of particles: 9.1 μm), 10 wt. % anhydrous dicalcium phosphate (DCPA) (CaHPO.sub.4), 10 wt. % CDA, and 2 wt. % HPMC.

[0196] The liquid phase (liquid/powder ratio=0.45 mL.Math.g.sup.−1) consists of: [0197] either 0.5 wt. % Na.sub.2HPO.sub.4 aqueous solution. [0198] or 5 wt. % Na.sub.2HPO.sub.4 aqueous solution, [0199] or ovine freshly harvested blood.

[0200] Graftys® GQSb10h cement paste samples were prepared by mixing 8 g of the powdered preparation with their respective liquid phase for 2 min to ensure the homogeneity of the obtained paste before analysis.

[0201] The measured properties are the following:

TABLE-US-00002 Na.sub.2HPO.sub.4 Na.sub.2HPO.sub.4 Fresh ovine Liquid component 0.5% 5% blood Initial setting time (min) 29 ± 2 14 ± 1 26 ± 1 Compressive strength  1 ± 0  3 ± 1 0.5 ± 0  at 6 h (MPa) Compressive strength 21 ± 3  7 ± 0 11 ± 1 at 24 h (Mpa) Compressive strength 26 ± 1 17 ± 2 15 ± 2 at 72 h (MPa) Compressive strength 32 ± 2 24 ± 2 21 ± 1 at 336 h (MPa)

[0202] Blood addition effect as observed in examples 1, 2 and 3 observed with HBS composition is here observed on a QS composition presenting a powder average size >9 μm.

Example 7 (Comparative): Comparison of the Properties of a Composition According to the Invention (with Blood as Liquid Component) with the Properties of a Composition with Plasma as Liquid Component (Graftys® HBS Vs Graftys® HBS+Plasma)

[0203] Graftys® HBS is a mixture of 78 wt. % α-tricalcium phosphate (α-TCP) (Ca.sub.3(PO.sub.4).sub.2)(average equivalent diameter of particles: 12 μm), 5 wt. % dicalcium phosphate dihydrate (DCPD) (CaHPO.sub.4, 2H.sub.2O), 5 wt. % monocalcium phosphate monohydrate (MCPM) (Ca(H.sub.2PO.sub.4).sub.2, H.sub.2O), 10 wt. % CDA (Ca.sub.10-x[ ].sub.x(HPO.sub.4).sub.y(PO.sub.4).sub.6-y(OH).sub.2-z[ ].sub.z), 2 wt. % hydroxypropyl methyl cellulose (HPMC) (E4 M®, Colorcon-Dow Chemical, Bougival, France).

[0204] The liquid phase (liquid/powder ratio=0.5 mL.Math.g.sup.−1) consists of: [0205] either 5 wt. % Na.sub.2HPO.sub.4 aqueous solution, [0206] or plasma obtained from ovine freshly harvested blood.

[0207] Plasma was obtained after blood centrifugation for 15 min at 1,800 g at room temperature (RT).

[0208] Graftys® HBS cement paste samples were prepared by mixing 8 g of the powdered preparation with their respective liquid phase for 2 min to ensure the homogeneity of the obtained paste before analysis.

[0209] The measured properties are as shown in the below table:

TABLE-US-00003 Na.sub.2HPO.sub.4 Fresh ovine Liquid component 5% plasma Initial setting time (min) 15 ± 2 Not measurable Compressive strength 14 + 2 Not measurable at 72 h (MPa)

[0210] Replacing HBS liquid component by plasma does not provide suitable cement for bone grafting surgery in term of both setting time and compressive strength.

Example 8: Compositions Comprising a Therapeutic Agent, and Optionally a Contrast Agent

[0211] Graftys® MIA is a mixture of 78 wt. % α-tricalcium phosphate (α-TCP) (Ca.sub.3(PO.sub.4).sub.2)(average equivalent diameter of particles: 12 μM), 5 wt. % dicalcium phosphate dihydrate (DCPD) (CaHPO.sub.4, 2H.sub.2O), 5 wt. % monocalcium phosphate monohydrate (MCPM) (Ca(H.sub.2PO.sub.4).sub.2, H.sub.2O), 10 wt. % CDA (Ca.sub.10-x[ ].sub.x(HPO.sub.4).sub.y (PO.sub.4).sub.6-y(OH).sub.2-z[ ].sub.z), partially loaded with Alendronate; 2 wt. % hydroxypropyl methyl cellulose (HPMC) (E4 M®, Colorcon-Dow Chemical, Bougival, France). The solid phase contains 0.56 mg of Alendronate per g of cement.

[0212] The liquid phase (liquid/powder ratio=0.5 mL.Math.g.sup.−1) consists of: [0213] either 5 wt. % Na.sub.2HPO.sub.4 aqueous solution, [0214] or ovine freshly harvested blood, [0215] or ovine freshly harvested blood+Xenetix (168 mG of Iodine/mL of blood).

[0216] Graftys® HBS cement paste samples were prepared by mixing 8 g of the powdered preparation with their respective liquid phase for 2 min to ensure the homogeneity of the obtained paste before analysis.

[0217] The measured properties are as shown in the below table:

TABLE-US-00004 Na.sub.2HPO.sub.4 Fresh ovine Fresh ovine Liquid component 5% blood blood + Xenetix ® Initial setting time (min) <15 22 ± 2 39 ± 5 Compressive strength 18 ± 2 15 ± 2 10 ± 2 at 72 h (MPa)

[0218] Adding Xenetix® in blood increases cement setting time and decreases its compressive strength. However those two handling properties look still compatible with bone grafting surgery.