Abstract: Controlled release silica sol-gels are room temperature processed, porous, resorbable, and
biocompatible materials. Many molecules including drugs, proteins, and growth factors can be
released from sol-gels, and the quantity and duration of the release can vary widely. Processing
parameters render these release properties exquisitely versatile . The synthesis of controlled
release sol-gels involves several steps: an acid-catalyzed hydrolysis to form a sol with the molecules
included, followed by casting, aging, and drying. Additional steps such as grinding and sieving are
required to produce sol-gel granules of a desirable size. In this study, we focus on the synthesis of
controlled release sol-gel microspheres by using a novel process, which involves only two steps:sol
formation followed by emulsification. Sol-gel microspheres containing either vancomycin
(antibiotic) or bupivacaine (analgesic) were successfully synthesized via this synthesis route. Both
drugs showed controlled, load-dependent and time-dependent release from the microspheres. The in
vitro release properties of sol-gel microspheres were different from those of sol-gel granules
produced by grinding and sieving. In comparison to a fast, short-term release from the granules, the
release from the microspheres was slower and of longer duration. In addition, the degradation rate of
microspheres was significantly slower than that of the granules. These data enable the use of sol-gel
powders for controlled long-term release.
Abstract: Apatite nuclei were synthesized by raising pH of simulated body fluid (SBF). Poly (lactic
acid) (PLA) microspheres were soaked in apatite nuclei suspension, and then apatite nuclei were
attached to surfaces of the PLA microspheres. When these PLA microspheres were soaked in SBF,
apatite nuclei on the PLA microspheres induced HAp. As a result, PLA microspheres coated with
HAp were fabricated. The HAp-coated PLA microspheres were soaked in acetone. The PLA core was
dissolved out, and then consequently hollow microcapsules constructed of HAp were fabricated. As
HAp microcapsules have properties of bioaffinity and non-toxicity, they were expected to be
applicable to an excellent carrier of drug delivery system.
Abstract: Calcium phosphate (CaP) biomaterials containing Chinese medicine, Danshen (Salvia
Miltiorrhiza Bunge, SMB), have been synthesized in our previous study via the wet chemical
method. However, CaP biomaterials were generally synthesized in the alkaline solution. The
purpose of the present study was to investigate the effect of pH on SMB and the influence of SMB
on the synthesis of CaP biomaterials. The SMB solutions of different pH from 5.0 to 10.0, were
scanned with the UV-VIS spectrophotometer (UV-VIS) in the wavelength ranged from 200.00 to
400.00 nm. CaP biomaterials containing SMB were synthesized from (NH4)2HPO4, Ca(NO3)2,
NH4OH and SMB. The filtrates of the wet synthesis of CaP biomaterials containing SMB were
measured by UV-VIS. The synthesized CaP biomaterials containing SMB were characterized by the
X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The results showed
that the maximum absorption peak appeared at 281.00 nm for solutions of pH 5.0, 6.0 and 7.0.
Although there were a new absorption peaks as the pH were 8.0 and 9.0, the absorption curves of
SMB became similar to that of SMB as pH at 7.0 after the pH were readjusted to 7.0. The
absorption peak appeared an Einstein shift to 347.00 nm at pH 10.0, which did not return to 281.00
nm when the pH of SMB solution was readjusted to 7.0. The absorption peak of filtrates containing
SMB of CaP biomaterials reaction system was still at 281.00 nm when their pH was 7.0 and 8.0.
Moreover, SMB had no obvious effect on the phase component and functional groups of products.
Hence, it could be predicted that calcium phosphate biomaterials containing SMB, such as DCPD
and TCP containing SMB, which could be prepared at the pH ranged from 5.0 to 9.0.
Abstract: The time-dependent variation of the protein release from protein incorporated apatite
cake in PBS solution was studied. When protein incorporated apatite cakes were immersed in PBS,
the volume of cakes dropped for 1 day of soaking period and the shrinkage of specimen seems to be
stabilized after 2 or 3 days soaking in PBS. The quantity of released protein from protein
incorporated apatite cake was increased with an increase of soaking period. Around several % of
protein came from the protein incorporated apatite cake in PBS for 2 weeks. The time-dependent
protein release was relatively high for 1 day of soaking period, after that it slowly decreased.
Compared to the decrease in volume of cake, the quantity ratio of released protein and total
incorporated protein was less, which may be associated with recrystallization of the apatite hydrogel.
FE-SEM observation revealed both crystals formed in air or under N2 atmosphere had similar rod
like shape, and seems to be almost same in size. The change of surface appearance between 1 day
and 4 days or longer soaking may be due to the dissolution of the surface layer and its
recrystallization. The aggregate of apatite crystals formed in air is found to be compact, but some
small cavities are observed in the specimens soaked in PBS for 4 – 11 days. The particle size of
protein incorporated apatite were almost similar, independent on the soaking period. But the shape
of apatite in aqueous solution is changing from square and angular shape to round shape.
Abstract: Bisphosphonates (BP) are drugs currently administered orally to treat diseases
characterised by an excessive bone resorption. Alternative and more efficient delivery routes and
more potent compounds are being investigated. Three implantable delivery systems, which allow
the controlled release of therapeutic agents from the device core, are examined in this paper. (4-
(aminomethyl) benzene) bisphosphonic acid (ABBP) was incorporated on
Ca8.8Na0.8(PO4)4.8(CO3)1.2(OH)0.4F1.6 particles by refluxing the powder in a 60 mmol suspension in
acetone at 60°C for 5 hours. 4-aminophenyl acetic bisphosphonate monosodium salt (APBP) and 1-
H-indole-3-acetic bisphosphonate monosodium (IBP) were loaded on Ca10(PO4)6(OH)1F1 ceramic
bodies by stirring the ceramic bodies in 0.04M BP solutions. Injectable acrylic cements based on
self-curing formulations of methyl methacrylate (MMA) and vitamin E were loaded with APBP and
IBP. The incorporation of ABBP was confirmed by MAS-NMR spectroscopy. Modified powder
shows two different phosphorous environments, the first one at 2.91 ppm can be assigned to the
apatite base and the second one at 18.0 ppm has to be attributed to the phosphonic group of the
ABBP. The IBP addition on ceramic surfaces did not decrease the number of osteoclast colonies
and appeared to improve the performance of the HA as a surface for osteoblast culture. A
therapeutic dosage of APBP and IBP can be achieved from acrylic cements that showed lack of
toxicity and an increased cellular activity and proliferation.
Abstract: Hydroxyapatite(HA) nanoparticles with hydrophobic surface have been synthesized
using mono-alkyl phosphate (MAP) as modifier by hydrothermal synthesis method. The
drug-loaded nano-HA/ Poly(ε-caprolactone)（PCL）composite microspheres and drug-load PCL
microspheres were fabricated by an S/O/W emulsion solvent evaporation method. The microspheres
morphology was investigated by scanning electron microscopy (SEM). Drug distribution in
microsphere matrix was studied by confocal laser scanning microscope (CLSM). The results
showed that the drug distributed evenly in the drug-HA-PCL microspheres, but only around the
surface of the drug-PCL microspheres. The drug release profile showed that the nano-HA/PCL
hybrid microspheres had low initial burst and could release continually for 90 days. This kind of
hybrid microspheres can be used as a promising long-term drug delivery system in the bone.
Abstract: Hydroxyapatite (HAp)-alginate gels were developed as drug delivery carriers of the
anti-cancer drug, water-insoluble paclitaxel (Taxol). The spray-drying technique was employed for
loading the paclitaxel into spherical HAp microparticles with 1 to 20 μm in diameter. The
microparticles loaded with 2.4 or 7.3wt% of paclitaxel were then mixed with sodium alginate,
which was followed by Ca2+-mediated gelation. The compressive strength of the HAp-alginate gels
and the release of paclitaxel from the gels in a medium were investigated in vitro. The alginate
matrix was effective for the achievement of controlled release of anti-cancer drugs.
Abstract: Nanocomposites consisting of biologically active ions, which can enhance cell viability
and activate gene expression, are regarded as promising bone regenerative materials. We report a
new method for the layer-by-layer (LbL) assembly of biologically active strontium ions in the
core-shell Silica@OCP system for an efficient controlled-release. The strontium ions were
assembled by using a pH-responsive electrostatic interaction to generate three-dimensional
gradients within the silica nanospheres, and then a porous OCP (octacalcium phosphate) shells was
coated on the microunits tailored by polyelectrolyte molecules. This core-shell-like microstructure
can achieve the multicomponents administration and controlled release of essential trace silicon and
zinc ions based on the barrier effect of OCP shell and pH-dependent manner, respectively.
Abstract: Autologous bone chips are widely used in orthopedic surgery to fill large defects due to
osteoinductive property but are limited in quantity. Several groups have reported the formation of
mineralized bone after implantation of bioceramics in ectopic sites of different animals. However,
osteoinduction by bioceramics has not yet proved to be equivalent to those of autologous bone. In
this study, we compare the bone inducing capability of autologous bone chips and synthetic
biphasic calcium phosphate (BCP) ceramics granules sintered at various temperatures. Both
materials were implanted in muscles and femurs of goats inside hollow containers for 6, 12 and 24
weeks and analyzed by histology. This study showed that bone tissue formed in contact with micro
porous ceramics sintered at low temperature as well as autologous bone chips both in ectopic and
intrafemoral sites of goats.