Bone Substitute

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Shahram Ghanaati - One of the best experts on this subject based on the ideXlab platform.

  • addition of blood to a phycogenic Bone Substitute leads to increased in vivo vascularization
    Biomedical Materials, 2015
    Co-Authors: Mike Barbeck, Stevo Najman, Sanja Stojanovic, žarko Mitic, Jelena živkovic, Joseph Choukroun, P Kovacevic, Robert Sader, C J Kirkpatrick, Shahram Ghanaati
    Abstract:

    The present study aimed to analyze the effects of the addition of blood to the phycogenic Bone Substitute Algipore® on the severity of in vivo tissue reaction. Initially, Fourier-transform infrared spectroscopy (FTIR) of the Bone Substitute was conducted to analyze its chemical composition. The subcutaneous implantation model in Balb/c mice was then applied for up to 30 d to analyze the tissue reactions on the basis of specialized histochemical, immunohistochemical, and histomorphometrical methods. The data of the FTIR analysis showed that the phycogenic Bone Substitute material is mainly composed of hydroxyapatite with some carbonate content. The in vivo analyses revealed that the addition of blood to Algipore® had a major impact on both angiogenesis and vessel maturation. The higher vascularization seemed to be based on significantly higher numbers of multinucleated TRAP-positive cells. However, mostly macrophages and a relatively low number of multinucleated giant cells were involved in the tissue reaction to Algipore®. The presented data show that the addition of blood to a Bone Substitute impacts the tissue reaction to it. In particular, the immune response and the vascularization were influenced, and these are believed to have a major impact on the regenerative potential of the process of Bone tissue regeneration.

  • nanocrystalline hydroxyapatite Bone Substitute leads to sufficient Bone tissue formation already after 3 months histological and histomorphometrical analysis 3 and 6 months following human sinus cavity augmentation
    Clinical Implant Dentistry and Related Research, 2013
    Co-Authors: Mike Barbeck, Shahram Ghanaati, Ines Willershausen, Benjamin W Thimm, Stefan Stuebinger, Tadas Korzinskas, Karina Obreja, Constantin A Landes, C J Kirkpatrick
    Abstract:

    Purpose: In this study the de novo Bone formation capacity of a nanocrystalline hydroxyapatite Bone Substitute was assessed 3 and 6 months after its insertion into the human sinus cavity. Materials and Methods: Sinus cavity augmentation was performed in a total of 14 patients (n = 7 implantation after 3 months; n = 7 implantation after 6 months) with severely atrophic maxillary Bone. The specimens obtained after 3 and 6 months were analyzed histologically and histomorphometrically with special focus on Bone metabolism within the residual Bone and the augmented region. Results: This study revealed that Bone tissue formation started from the Bone-biomaterial-interface and was directed into the most cranial parts of the augmented region. There was no statistically significant difference in new Bone formation after 3 and 6 months (24.89 1 10.22% vs 31.29 1 2.29%), respectively. Conclusions: Within the limits of the present study and according to previously published data, implant insertion in regions augmented with this Bone Substitute material could be considered already after 3 months. Further clinical studies with Bone Substitute materials are necessary to validate these findings.

  • implantation of silicon dioxide based nanocrystalline hydroxyapatite and pure phase beta tricalciumphosphate Bone Substitute granules in caprine muscle tissue does not induce new Bone formation
    Head & Face Medicine, 2013
    Co-Authors: Mike Barbeck, Robert Sader, Shahram Ghanaati, Ines Willershausen, S E Udeabor, Oliver Kuenzel, James C Kirkpatrick
    Abstract:

    Background Osteoinductive Bone Substitutes are defined by their ability to induce new Bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different Bone Substitute materials in caprine muscle tissue.

  • Implantation of silicon dioxide-based nanocrystalline hydroxyapatite and pure phase beta-tricalciumphosphate Bone Substitute granules in caprine muscle tissue does not induce new Bone formation
    Head & Face Medicine, 2013
    Co-Authors: Shahram Ghanaati, Mike Barbeck, Ines Willershausen, S E Udeabor, Oliver Kuenzel, Robert A. Sader, C. James Kirkpatrick
    Abstract:

    Background Osteoinductive Bone Substitutes are defined by their ability to induce new Bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different Bone Substitute materials in caprine muscle tissue. Materials and methods One gram each of either a porous beta-tricalcium phosphate (β-TCP) or an hydroxyapatite/silicon dioxide (HA/SiO_2)-based nanocrystalline Bone Substitute material was implanted in several muscle pouches of goats. The biomaterials were explanted at 29, 91 and 181 days after implantation. Conventional histology and special histochemical stains were performed to detect osteoblast precursor cells as well as mineralized and unmineralized Bone matrix. Results Both materials underwent cellular degradation in which tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and TRAP-negative multinucleated giant cells were involved. The ß-TCP was completely resorbed within the observation period, whereas some granules of the HA-groups were still detectable after 180 days. Neither osteoblasts, osteoblast precursor cells nor extracellular Bone matrix were found within the implantation bed of any of the analyzed biomaterials at any of the observed time points. Conclusions This study showed that ß-TCP underwent a faster degradation than the HA-based material. The lack of osteoinductivity for both materials might be due to their granular shape, as osteoinductivity in goat muscle has been mainly attributed to cylindrical or disc-shaped Bone Substitute materials. This hypothesis however requires further investigation to systematically analyze various materials with comparable characteristics in the same experimental setting.

Guy Daculsi - One of the best experts on this subject based on the ideXlab platform.

  • The safety and efficacy of an injectable Bone Substitute in dental sockets demonstrated in a human clinical trial.
    Biomaterials, 2007
    Co-Authors: Pierre Weiss, Guy Daculsi, Paul Pilet, Pierre Layrolle, Léon Philippe Clergeau, Bénédicte Enckel, Yves Amouriq, Bernard Giumelli
    Abstract:

    This study is the first report of a clinical evaluation of an injectable Bone Substitute (IBS). This IBS was prepared by suspending biphasic calcium phosphate (BCP) particles with diameters ranging between 80 and 200 microm in a water-soluble cellulose polymer carrier phase. It was used for filling Bone defects after tooth extractions in 11 patients. The first objective of the study was to investigate the safety of the filler material. The second objective was to investigate the efficacy of the material for filling human tooth sockets and preventing alveolar Bone loss. Radiographic density measurements of the surgical sites gradually increased to those of the surrounding host Bone. Three years after surgery, small biopsies of the implanted areas were harvested and analyzed by using micro-computed tomography, non-decalcified histology and histomorphometry. The BCP granules appeared in direct contact with mineralized Bone tissue, thereby supporting Bone growth. A gradual substitution of the filler by Bone tissue was observed thus preserving the height of the alveolar Bone crest.

  • Bone repair using a new injectable self-crosslinkable Bone Substitute.
    Journal of Orthopaedic Research, 2006
    Co-Authors: Borhane Fellah, Guy Daculsi, Pierre Weiss, Olivier Gauthier, Thierry Rouillon, Paul Pilet, Pierre Layrolle
    Abstract:

    A new injectable and self-crosslinkable Bone Substitute (IBS2) was developed for filling Bone defects. The IBS2 consisted of a chemically modified polymer solution mixed with biphasic calcium phosphate (BCP) ceramic particles. The polymer hydroxypropylmethyl cellulose was functionalized with silanol groups (Si-HPMC) and formed a viscous solution (3 wt %) in alkaline medium. With a decrease in pH, self-hardening occurred due to the formation of intermolecular -Si-O- bonds. During setting, BCP particles, 40 to 80 microm in diameter, were added to the polymer solution at a weight ratio of 50/50. The resulting injectable material was bilaterally implanted into critically sized Bone defects at the distal femoral epiphyses of nine New Zealand White rabbits. The IBS2 filled the Bone defects entirely and remained in place. After 8 weeks, Bone had grown centripetally and progressed towards the center of the defects. Newly formed Bone, ceramic, and nonmineralized tissue ratios were 24.6% +/- 5.6%, 21.6% +/- 5.8%, and 53.7% +/- 0.1%, respectively. Mineralized and mature Bone was observed between and in contact with the BCP particles. The Bone/ceramic apposition was 73.4% +/- 10.6%. The yield strength for the IBS2-filled defects was 16.4 +/- 7.2 MPa, significantly higher than for the host trabecular Bone tissue (2.7 +/- 0.4 MPa). This study showed that BCP particles supported the Bone healing process by osteoconduction while the Si-HPMC hydrogel created intergranular space for Bone ingrowth. This new injectable and self-crosslinkable Bone Substitute could be used conveniently in orthopedic surgery for filling critical-size Bone defects.

  • Bone repair using a new injectable self crosslinkable Bone Substitute
    Journal of Orthopaedic Research, 2006
    Co-Authors: Borhane Fellah, Guy Daculsi, Pierre Weiss, Olivier Gauthier, Thierry Rouillon, Paul Pilet, Pierre Layrolle
    Abstract:

    A new injectable and self-crosslinkable Bone Substitute (IBS2) was developed for filling Bone defects. The IBS2 consisted of a chemically modified polymer solution mixed with biphasic calcium phosphate (BCP) ceramic particles. The polymer hydroxypropylmethyl cellulose was functionalized with silanol groups (Si-HPMC) and formed a viscous solution (3 wt %) in alkaline medium. With a decrease in pH, self-hardening occurred due to the formation of intermolecular SiO bonds. During setting, BCP particles, 40 to 80 µm in diameter, were added to the polymer solution at a weight ratio of 50/50. The resulting injectable material was bilaterally implanted into critically sized Bone defects at the distal femoral epiphyses of nine New Zealand White rabbits. The IBS2 filled the Bone defects entirely and remained in place. After 8 weeks, Bone had grown centripetally and progressed towards the center of the defects. Newly formed Bone, ceramic, and nonmineralized tissue ratios were 24.6% ± 5.6%, 21.6% ± 5.8%, and 53.7% ± 0.1%, respectively. Mineralized and mature Bone was observed between and in contact with the BCP particles. The Bone/ceramic apposition was 73.4% ± 10.6%. The yield strength for the IBS2-filled defects was 16.4 ± 7.2 MPa, significantly higher than for the host trabecular Bone tissue (2.7 ± 0.4 MPa). This study showed that BCP particles supported the Bone healing process by osteoconduction while the Si-HPMC hydrogel created intergranular space for Bone ingrowth. This new injectable and self-crosslinkable Bone Substitute could be used conveniently in orthopedic surgery for filling critical-size Bone defects. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

  • a new injectable Bone Substitute combining poly e caprolactone microparticles with biphasic calcium phosphate granules
    Biomaterials, 2001
    Co-Authors: P. Iooss, Gaël Grimandi, Guy Daculsi, Corinne Merle
    Abstract:

    Previous studies have shown the e!ectiveness of an injectable Bone Substitute (IBS) composed of biphasic calcium phosphate in 2% hydroxypropyl methylcellulose gel (50/50 w/w). A therapeutic agent in the form of a drug can be added to the biomaterial by encapsulation into microparticles to protect the active agent, control its release and preserve the material rheological properties. Poly(-caprolactone) was used in this study because of its biocompatibility and resorbability, as tested in orthopaedic implants and surgical sutures. Particles (80}200m) were manufactured by a solvent evaporation}extraction process (1g of polymer, 11 } 15m l methylene chloride, with a stirring speed of 400}600 rpm) and introduced into the IBS in a 5}50% (V/V) range. Injectability was evaluated by texture analysis. With less than 45% of particles, the material had rheological properties similar to those of the reference IBS, whereas injectability decreased markedly with more than 45% of particles. A preliminary in vitro release study showed that this type of triphasic IBS could be e$cient for drug delivery systems with osteoconduction properties. 2001Published by Elsevier Science Ltd.

  • A new injectable Bone Substitute combining poly(ε-caprolactone) microparticles with biphasic calcium phosphate granules
    Biomaterials, 2001
    Co-Authors: P. Iooss, A. M. Le Ray, Gaël Grimandi, Guy Daculsi, Corinne Merle
    Abstract:

    Previous studies have shown the effectiveness of an injectable Bone Substitute (IBS) composed of biphasic calcium phosphate in 2% hydroxypropyl methylcellulose gel (50/50 w/w). A therapeutic agent in the form of a drug can be added to the biomaterial by encapsulation into microparticles to protect the active agent, control its release and preserve the material rheological properties. Poly(ε-caprolactone) was used in this study because of its biocompatibility and resorbability, as tested in orthopaedic implants and surgical sutures. Particles (80-200 μm) were manufactured by a solvent evaporation-extraction process (1 g of polymer, 11-15 ml methylene chloride, with a stirring speed of 400-600 rpm) and introduced into the IBS in a 5-50% (V/V) range. Injectability was evaluated by texture analysis. With less than 45% of particles, the material had rheological properties similar to those of the reference IBS, whereas injectability decreased markedly with more than 45% of particles. A preliminary in vitro release study showed that this type of triphasic IBS could be efficient for drug delivery systems with osteoconduction properties. © 2001 Published by Elsevier Science Ltd.

David Knaack - One of the best experts on this subject based on the ideXlab platform.

  • alpha-BSM: a biomimetic Bone Substitute and drug delivery vehicle.
    Clinical orthopaedics and related research, 1999
    Co-Authors: D.d. Lee, A Tofighi, A Majahad, Maria Aiolova, P Chakravarthy, Andrew Catalano, David Knaack
    Abstract:

    alpha-BSM is a biomimetic endothermically setting apatitic calcium phosphate Bone Substitute material. Its injectability and ability to harden at body temperature in the presence of physiologic saline, and other buffering agents, makes it an attractive clinical Bone Substitute and delivery vehicle for therapeutic agents in orthopaedic and dental applications. In osseous tissue, alpha-BSM alone remodels into Bone and promotes Bone healing. alpha-BSM treatment has been shown in several animal models to be effective in promoting healing of surgically created critical size defects and restoring Bone biomechanical strength to values equal to or greater than values achieved with autograft controls. In vitro studies with alpha-BSM containing gentamicin show that antibiotics can be incorporated stably into alpha-BSM and that the release kinetics can be controlled with the appropriate formulation and preparative procedures. Growth factors and enzymes also are compatible with the alpha-BSM setting reaction. The incorporation of recombinant human Bone morphogenetic protein-2 with alpha-BSM was shown to be effective in stimulating Bone formation and accelerating restoration of the differentiated phenotype in an osteotomy model. Clinical trial investigators in Europe currently are using alpha-BSM implantations for treatment of fractures and other indications.

  • α-BSM®: A biomimetic Bone Substitute and drug delivery vehicle
    Clinical Orthopaedics and Related Research, 1999
    Co-Authors: D.d. Lee, A Tofighi, A Majahad, Maria Aiolova, P Chakravarthy, Andrew Catalano, David Knaack
    Abstract:

    α-BSM® is a biomimetic endothermically setting apatitic calcium phosphate Bone Substitute material. Its injectability and ability to harden at body temperature in the presence of physiologic saline, and other buffering agents, makes it an attractive clinical Bone Substitute and delivery vehicle for therapeutic agents in orthopaedic and dental applications. In osseous tissue, α-BSM® alone remodels into Bone and promotes Bone healing, α-BSM® treatment has been shown in several animal models to be effective in promoting healing of surgically created critical size defects and restoring Bone biomechanical strength to values equal to or greater than values achieved with autograft controls. In vitro studies with α-BSM® containing gentamicin show that antibiotics can be incorporated stably into α-BSM® and that the release kinetics can be controlled with the appropriate formulation and preparative procedures. Growth factors and enzymes also are compatible with the α-BSM® setting reaction. The incorporation of recombinant human Bone morphogenetic protein-2 with α-BSM® was shown to be effective in stimulating Bone formation and accelerating restoration of the differentiated phenotype in an osteotomy model. Clinical trial investigators in Europe currently are using α-BSM® implantations for treatment of fractures and other indications.

  • resorbable calcium phosphate Bone Substitute
    Journal of Biomedical Materials Research, 1998
    Co-Authors: David Knaack, A Tofighi, Maria Aiolova, M E P Goad, P Chakravarthy
    Abstract:

    The in vitro and in vivo properties of a novel, fully resorbable, apatitic calcium phosphate Bone Substitute (ABS) are described. The ABS was prepared from calcium phosphate precursors that were hydrated to form an injectable paste that hardens endothermically at 37 °C to form a poorly crystalline apatitic calcium phosphate (PCA). The PCA reaction product is stable in vivo as determined by FTIR and XRD analysis of rabbit intramuscular implants of ABS retrieved 4, 7, and 14 days postimplantation. Bone formation and resorption charactcristics of the ABS material were characterized in a canine femoral slot defect model. Femoral slot defects in dogs were filled with either autologous Bone implants or the ABS material. Sections of femoral Bone defect site from animals sacrificed at 3. 4, 12, 26, and 52 weeks demonstrated that new Bone formation proceeded similarly in both autograft and ABS filled slots. Defects receiving either material were filled with trabecular Bone in the first 3 to 4 weeks after implantation: lamellar or cortical Bone formation was well established by week 12. New Bone formation in ABS filled defects followed a time course comparable to autologous Bone graft filled defects. Histomorphometric evaluation of ABS resorption and new Bone formation indicated that the ABS material was greater than 99% resorbed within 26 weeks; residual ABS occupied 0.36 ± 0.36% (SEM, n = 4) of the original defect area at 26 weeks. Quantitatively and qualitatively, the autograft and ABS were associated with similar new Bone growth and defect filling characteristics.

Mike Barbeck - One of the best experts on this subject based on the ideXlab platform.

  • addition of blood to a phycogenic Bone Substitute leads to increased in vivo vascularization
    Biomedical Materials, 2015
    Co-Authors: Mike Barbeck, Stevo Najman, Sanja Stojanovic, žarko Mitic, Jelena živkovic, Joseph Choukroun, P Kovacevic, Robert Sader, C J Kirkpatrick, Shahram Ghanaati
    Abstract:

    The present study aimed to analyze the effects of the addition of blood to the phycogenic Bone Substitute Algipore® on the severity of in vivo tissue reaction. Initially, Fourier-transform infrared spectroscopy (FTIR) of the Bone Substitute was conducted to analyze its chemical composition. The subcutaneous implantation model in Balb/c mice was then applied for up to 30 d to analyze the tissue reactions on the basis of specialized histochemical, immunohistochemical, and histomorphometrical methods. The data of the FTIR analysis showed that the phycogenic Bone Substitute material is mainly composed of hydroxyapatite with some carbonate content. The in vivo analyses revealed that the addition of blood to Algipore® had a major impact on both angiogenesis and vessel maturation. The higher vascularization seemed to be based on significantly higher numbers of multinucleated TRAP-positive cells. However, mostly macrophages and a relatively low number of multinucleated giant cells were involved in the tissue reaction to Algipore®. The presented data show that the addition of blood to a Bone Substitute impacts the tissue reaction to it. In particular, the immune response and the vascularization were influenced, and these are believed to have a major impact on the regenerative potential of the process of Bone tissue regeneration.

  • nanocrystalline hydroxyapatite Bone Substitute leads to sufficient Bone tissue formation already after 3 months histological and histomorphometrical analysis 3 and 6 months following human sinus cavity augmentation
    Clinical Implant Dentistry and Related Research, 2013
    Co-Authors: Mike Barbeck, Shahram Ghanaati, Ines Willershausen, Benjamin W Thimm, Stefan Stuebinger, Tadas Korzinskas, Karina Obreja, Constantin A Landes, C J Kirkpatrick
    Abstract:

    Purpose: In this study the de novo Bone formation capacity of a nanocrystalline hydroxyapatite Bone Substitute was assessed 3 and 6 months after its insertion into the human sinus cavity. Materials and Methods: Sinus cavity augmentation was performed in a total of 14 patients (n = 7 implantation after 3 months; n = 7 implantation after 6 months) with severely atrophic maxillary Bone. The specimens obtained after 3 and 6 months were analyzed histologically and histomorphometrically with special focus on Bone metabolism within the residual Bone and the augmented region. Results: This study revealed that Bone tissue formation started from the Bone-biomaterial-interface and was directed into the most cranial parts of the augmented region. There was no statistically significant difference in new Bone formation after 3 and 6 months (24.89 1 10.22% vs 31.29 1 2.29%), respectively. Conclusions: Within the limits of the present study and according to previously published data, implant insertion in regions augmented with this Bone Substitute material could be considered already after 3 months. Further clinical studies with Bone Substitute materials are necessary to validate these findings.

  • implantation of silicon dioxide based nanocrystalline hydroxyapatite and pure phase beta tricalciumphosphate Bone Substitute granules in caprine muscle tissue does not induce new Bone formation
    Head & Face Medicine, 2013
    Co-Authors: Mike Barbeck, Robert Sader, Shahram Ghanaati, Ines Willershausen, S E Udeabor, Oliver Kuenzel, James C Kirkpatrick
    Abstract:

    Background Osteoinductive Bone Substitutes are defined by their ability to induce new Bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different Bone Substitute materials in caprine muscle tissue.

  • Implantation of silicon dioxide-based nanocrystalline hydroxyapatite and pure phase beta-tricalciumphosphate Bone Substitute granules in caprine muscle tissue does not induce new Bone formation
    Head & Face Medicine, 2013
    Co-Authors: Shahram Ghanaati, Mike Barbeck, Ines Willershausen, S E Udeabor, Oliver Kuenzel, Robert A. Sader, C. James Kirkpatrick
    Abstract:

    Background Osteoinductive Bone Substitutes are defined by their ability to induce new Bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different Bone Substitute materials in caprine muscle tissue. Materials and methods One gram each of either a porous beta-tricalcium phosphate (β-TCP) or an hydroxyapatite/silicon dioxide (HA/SiO_2)-based nanocrystalline Bone Substitute material was implanted in several muscle pouches of goats. The biomaterials were explanted at 29, 91 and 181 days after implantation. Conventional histology and special histochemical stains were performed to detect osteoblast precursor cells as well as mineralized and unmineralized Bone matrix. Results Both materials underwent cellular degradation in which tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and TRAP-negative multinucleated giant cells were involved. The ß-TCP was completely resorbed within the observation period, whereas some granules of the HA-groups were still detectable after 180 days. Neither osteoblasts, osteoblast precursor cells nor extracellular Bone matrix were found within the implantation bed of any of the analyzed biomaterials at any of the observed time points. Conclusions This study showed that ß-TCP underwent a faster degradation than the HA-based material. The lack of osteoinductivity for both materials might be due to their granular shape, as osteoinductivity in goat muscle has been mainly attributed to cylindrical or disc-shaped Bone Substitute materials. This hypothesis however requires further investigation to systematically analyze various materials with comparable characteristics in the same experimental setting.

Corinne Merle - One of the best experts on this subject based on the ideXlab platform.

  • a new injectable Bone Substitute combining poly e caprolactone microparticles with biphasic calcium phosphate granules
    Biomaterials, 2001
    Co-Authors: P. Iooss, Gaël Grimandi, Guy Daculsi, Corinne Merle
    Abstract:

    Previous studies have shown the e!ectiveness of an injectable Bone Substitute (IBS) composed of biphasic calcium phosphate in 2% hydroxypropyl methylcellulose gel (50/50 w/w). A therapeutic agent in the form of a drug can be added to the biomaterial by encapsulation into microparticles to protect the active agent, control its release and preserve the material rheological properties. Poly(-caprolactone) was used in this study because of its biocompatibility and resorbability, as tested in orthopaedic implants and surgical sutures. Particles (80}200m) were manufactured by a solvent evaporation}extraction process (1g of polymer, 11 } 15m l methylene chloride, with a stirring speed of 400}600 rpm) and introduced into the IBS in a 5}50% (V/V) range. Injectability was evaluated by texture analysis. With less than 45% of particles, the material had rheological properties similar to those of the reference IBS, whereas injectability decreased markedly with more than 45% of particles. A preliminary in vitro release study showed that this type of triphasic IBS could be e$cient for drug delivery systems with osteoconduction properties. 2001Published by Elsevier Science Ltd.

  • A new injectable Bone Substitute combining poly(ε-caprolactone) microparticles with biphasic calcium phosphate granules
    Biomaterials, 2001
    Co-Authors: P. Iooss, A. M. Le Ray, Gaël Grimandi, Guy Daculsi, Corinne Merle
    Abstract:

    Previous studies have shown the effectiveness of an injectable Bone Substitute (IBS) composed of biphasic calcium phosphate in 2% hydroxypropyl methylcellulose gel (50/50 w/w). A therapeutic agent in the form of a drug can be added to the biomaterial by encapsulation into microparticles to protect the active agent, control its release and preserve the material rheological properties. Poly(ε-caprolactone) was used in this study because of its biocompatibility and resorbability, as tested in orthopaedic implants and surgical sutures. Particles (80-200 μm) were manufactured by a solvent evaporation-extraction process (1 g of polymer, 11-15 ml methylene chloride, with a stirring speed of 400-600 rpm) and introduced into the IBS in a 5-50% (V/V) range. Injectability was evaluated by texture analysis. With less than 45% of particles, the material had rheological properties similar to those of the reference IBS, whereas injectability decreased markedly with more than 45% of particles. A preliminary in vitro release study showed that this type of triphasic IBS could be efficient for drug delivery systems with osteoconduction properties. © 2001 Published by Elsevier Science Ltd.