Study of controlled tetracycline release from porous calcium phosphate/polyhydroxybutyrate composites

2007 ◽  
Vol 61 (6) ◽  
Author(s):  
L’ Medvecký ◽  
R. Štulajterová ◽  
J. Briančin
Keyword(s):  
Calcium Phosphate ◽  
Release Rate ◽  
Saline Solution ◽  
Preparation Method ◽  
Porous Ceramics ◽  
Phosphate Buffer Saline Solution ◽  
Calcium Phosphate Ceramic ◽  
Burst Effect ◽  
Ceramic Samples ◽  
Oriented Texture

AbstractPorous calcium phosphate ceramics were prepared by sintering of mixtures of nanocrystalline apatitic calcium phosphate and fibrous natural cotton cellulose after pressing at temperatures of 1150 °C and 1250 °C. Micro-and macropores were present in microstructures of ceramic samples. The microstructures of porous ceramics were similar to those observed in bone tissues and fiber-like randomly oriented texture was observed in ceramics. Polyhydroxybutyrate (PHB) biopolymer layers are distributed homogeneously in the samples after evaporation of the diluent (chloroform) from the PHB vacuum impregnated porous samples. The tetracycline (TTC) release rate decreases with the content of polyhydroxybutyrate in the ceramic samples, which corresponds to the rise in amount of biopolymer displaced in the pores of ceramics. The concentration of TTC in the phosphate buffer saline solution varies almost linearly with time after the first seven hours from the start of the release of the calcium phosphate ceramic samples with 2.4 mass % of polyhydroxybutyrate. The initial burst effect was significantly depressed by the preparation method used.

Comparison of Osteoinduction by Autologous Bone and Biphasic Calcium Phosphate Ceramic in Goats

2007 ◽  
Vol 330-332 ◽  
pp. 1063-1066 ◽  
Author(s):  
Borhane H. Fellah ◽  
Olivier Gauthier ◽  
Pierre Weiss ◽  
Daniel Chappard ◽  
Pierre Layrolle
Keyword(s):  
Calcium Phosphate ◽  
Low Temperature ◽  
Bone Tissue ◽  
Orthopedic Surgery ◽  
Biphasic Calcium Phosphate ◽  
Porous Ceramics ◽  
Calcium Phosphate Ceramic ◽  
Autologous Bone ◽  
Osteoinductive Property

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.

Osteoconduction on, and Bonding to, Calcium Phosphate Ceramic Implants

1995 ◽  
Vol 414 ◽  
Author(s):  
D. M. Dziedzic ◽  
I. H. Savva ◽  
D. S. Wilkinson ◽  
J. E. Davies
Keyword(s):  
Extracellular Matrix ◽  
Calcium Phosphate ◽  
Bone Growth ◽  
De Novo ◽  
Porous Ceramics ◽  
Ceramic Surface ◽  
Scattered Electron ◽  
Calcium Phosphate Ceramic ◽  
Implant Surface ◽  
Bone Contact

AbstractCalcium phosphate ceramic blocks of three different densities, porous, intermediate and dense, were prepared by tape casting (total = 18), and implanted in the femora of 9 Wistar rats for 1 to 3 weeks. Following fixation, the tissue was prepared for examination by scanning electron microscopy (SEM) of freeze fractured specimens, or back-scattered electron imaging (BSEI) of polymethylmethacrylate (PMMA) embedded, undecalcified, sections. The results demonstrated that while all ceramics were osteoconductive, the 93 % dense implants showed no evidence of bone bonding as judged by the plane at which specimens separated or cracked during preparation for microscopy. The porous ceramics, on whose surfaces both multinucleated cells and osteoid tissue were observed at all implantation times, exhibited less bone contact than the other two groups. Both SEM and BSEI showed that there was bone growth into the microporosity of both intermediate and porous ceramics, pore size range 1−2μ m, to a depth of about 6μm. The latter corresponds to the thickness of natural bone lamellae. In all implants examined, de novo bone formed on the ceramic surface by the initial production of a biological cement-line like interfacial extracellular matrix. The results clearly show that osteoconduction and bone-bonding are distinct mechanistic phenomena. While we assume the former to be a consequence of protein adsorption events culminating in anchorage of osteoblasts to the implant surface, the latter is the result of mechanical interdigitation of the extracellular matrix, produced by osteoblasts, with the microtopography of the implant surface.

Microorganism-based monodisperse microcapsules: encapsulation of the fungicide tebuconazole and its controlled release properties

RSC Advances ◽  
2015 ◽  
Vol 5 (32) ◽  
pp. 25164-25170 ◽  
Author(s):  
Bo Zhang ◽  
Teng Zhang ◽  
Quanxi Wang ◽  
Tianrui Ren
Keyword(s):  
Controlled Release ◽  
Powdery Mildew ◽  
Drug Release ◽  
Release Rate ◽  
Drug Release Rate ◽  
Burst Effect ◽  
Initial Burst ◽  
Release System ◽  
Controlled Release System ◽  
Monodisperse Microcapsules

A controlled release system was prepared, it based on UF modified PCC cells in which TEB are loaded into cells. It can control the drug release rate, depress the initial “burst effect”, and was efficacious in controlling wheat powdery mildew.

Aging Studies of Pu-238 and -239 Containing Calcium Phosphate Ceramic Waste-forms

2013 ◽  
Vol 1518 ◽  
pp. 73-78 ◽  
Author(s):  
Shirley K. Fong ◽  
Brian L. Metcalfe ◽  
Randall D. Scheele ◽  
Denis M. Strachan
Keyword(s):  
Calcium Phosphate ◽  
Accelerated Aging ◽  
Waste Form ◽  
Calcium Phosphate Ceramic ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Aging Studies ◽  
Flow Through ◽  
Pyrochemical Reprocessing

ABSTRACTA calcium phosphate ceramic waste-form has been developed at AWE for the immobilisation of chloride containing wastes arising from the pyrochemical reprocessing of plutonium. In order to determine the long term durability of the waste-form, aging trials have been carried out at PNNL. Ceramics were prepared using Pu-239 and -238, these were characterised by PXRD at regular intervals and Single Pass Flow Through (SPFT) tests after approximately 5 yrs.While XRD indicated some loss of crystallinity in the Pu-238 samples after exposure to 2.8 x 1018 α decays, SPFT tests indicated that accelerated aging had not had a detrimental effect on the durability of Pu-238 samples compared to Pu-239 waste-forms.

Macroporous calcium phosphate ceramic for long bone surgery in humans and dogs. Clinical and histological study

1990 ◽  
Vol 24 (3) ◽  
pp. 379-396 ◽  
Author(s):  
G. Daculsi ◽  
N. Passuti ◽  
S. Martin ◽  
C. Deudon ◽  
R. Z. Legeros ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Histological Study ◽  
Long Bone ◽  
Calcium Phosphate Ceramic ◽  
Bone Surgery
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