Characterization of Various Apatites Powders Prepared by Ultrasonic Spray-Pyrolysis Technique

Aizawa, Mamoru; Hanazawa, Takashi; Itatani, Kiyoshi; Howell, F. Scott; Kishioka, Akira

doi:10.3363/prb1992.6.0_217

Cited by 10 publications

(8 citation statements)

References 2 publications

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“…Preparation of calcium-phosphate microspheres. As previously reported [8], the apparatus for the ultrasonic spray-pyrolysis was comprised of an atomizer, a heating part (mullite tube: 2.5 cm in I.D. and 1 m in height; electric furnace: 3 cm in I.D.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Calcium-Phosphate Microspheres by Salt-Assisted Ultrasonic Spray-Pyrolysis Technique and their Drug Release Behavior Using Anti-Angiogenic Agent, TNP-470

Matsueda

Emoto

Aizawa

2011

KEM

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Synthetic clcium phosphate based materials, such as hydroxyapatite (Ca10(PO4)6(OH)2; HAp) and tricalcium phosphate (Ca3(PO4)2; TCP), are compounds with high potential for clinical applications to orthopedic and dental region. In previous study, we have reported that the hollow and porous apatite microsphere could be prepared by salt-assisted ultrasonic spray-pyrolysis (SAUSP) technique using sodium chloride (NaCl). In this case, these microspheres have some problems of (i) decrease of dissolubility of microspheres and (ii) cytotoxicity arising from chloride ions elution. To overcome these disadvantages, we prepared novel microspheres by SAUSP technique using potassium nitrate (KNO3) instead of NaCl. The resulting microsphere was washed with pure water to remove the KNO3 phase. The particle shapes of the powders were observed by scanning electron microscopy (SEM); the diameters of the microspheres were of 0.5 - 3.0 m, and the fine pores with the sizes of ~50 nm were present on the surface of the microspheres. The TNP-470 agent as a model of drug were loaded on these microspheres with nano-pores in the surface. In the KNO3 concentration of 1.00 mol·dm-3, 70 % of the total TNP-470 from the microspheres was rapidly released within 1 h. The remaining 30 % was slowly released up to 24 h following immersion, and total amount of TNP-470 released from the microspheres was 42 g·mg-1.

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Section: Methodsmentioning

confidence: 99%

Preparation of Calcium-Phosphate Microspheres by Salt-Assisted Ultrasonic Spray-Pyrolysis Technique and their Drug Release Behavior Using Anti-Angiogenic Agent, TNP-470

Matsueda

Emoto

Aizawa

2011

KEM

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“…The calcium-phosphate ceramic microspheres were synthesized in our laboratory at Meiji University, as previously reported. (29,30) Briefly, the starting solution with a Ca ⁄ P ratio of 1:50 was prepared by mixing Ca(NO 3 ) 2 , (NH 4 ) 2 HPO 4 , and HNO 3 so that their concentrations were 0.60 mol ⁄ dm, 0.40 mol ⁄ dm 3 , and 0.10 mol ⁄ dm 3 , respectively. The upper-and lower-furnace temperatures were fixed at 850 and 300°C, respectively.…”

Section: Methodsmentioning

confidence: 99%

Novel chemoembolization using calcium‐phosphate ceramic microsphere incorporating TNP‐470, an anti‐angiogenic agent

et al. 2009

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The purpose of the present study was to develop a new method of chemoembolization to improve the therapeutic effectiveness and safety profile of cancer treatment. A chemoembolization approach was designed for human solid tumors using resorbable calcium-phosphate ceramic microspheres loaded with an agent anti-angiogenic to tumor vasculature in vivo. The human uterine sarcoma cell line FU-MMT-3 was used in this study because this tumor is aggressive and also exhibits a poor response to radiotherapy or any chemotherapy currently used. The calciumphosphate ceramic microspheres loaded with TNP-470, an antiangiogenic agent, were injected into FU-MMT-3 xenografts in nude mice three times per week for 8 weeks. The treatment using TNP-470-loaded microspheres suppressed tumor growth, compared to treatment with TNP-470 alone, microspheres alone, and the control. The mean tumor weight after treatment using TNP-470-loaded microspheres was significantly lower than that after treatment with microspheres alone. These ceramic microspheres were remarkably embolized in tumor microvessels as well as in the feeding arteries and a significant reduction of intratumoral vascularity was also demonstrated following treatment with TNP-470-loaded microspheres. Severe loss of body weight was not observed in any mice treated with the TNP-470-loaded microspheres, compared to treatment with TNP-470 alone. These results suggest that targeting tumor vasculature in human uterine sarcoma using calcium-phosphate microspheres might be more effective and safer than the treatment that employs anti-angiogenic agent alone. This new chemoembolization method incorporating an anti-angiogenic agent may contribute to the effective treatment of locally advanced or recurrent solid tumors. (Cancer Sci 2010; 101: 984-990) S arcomas, including carcinosarcomas, are uncommon, but are the most aggressive neoplasms among the known uterine malignancies.(1,2) It is well known that these tumors have poor responses to radiotherapy or any of the chemotherapeutic agents with substantial toxic effects that are currently in use.(1-4)The overall 5-year survival rate in all stages of uterine sarcomas is under 40%, which is significantly lower than that in other uterine cancers.(3) The standard treatments for these tumors, except for the early stages, have not yet been determined; thus, new therapeutic strategies must be immediately investigated. Recent studies, including that of the authors, have shown that rapid growth and early metastasis in these tumors might be associated with high angiogenic properties, in comparison to other uterine malignancies. (4)(5)(6) Radiotherapy is one of the most effective treatments for cancers. For deep-seated cancer, however, external irradiation provides only small doses and often causes damage to healthy tissue. Thus, chemoembolization approaches that use various biomaterials might be effective for treating these solid tumors, including cases that have already received radiotherapy.(7) Many biomaterials are used as substitutes for human ...

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“…The sample powders were prepared by spray-pyrolyzing the starting solution using the ultrasonic vibrator with a frequency of 2.4 MHz in the hot zone. The hot zone in the present USSP apparatus was composed of two electric furnaces: the lower furnace was used for the drying of the droplets (300 °C) and the upper furnace was used for the spray-pyrolysis (850 °C) [15].…”

Section: Preparation Of Naap Powders Using Ussp Technique and Ceramic...mentioning

confidence: 99%

Fabrication of Sodium-Substituted Hydroxyapatite Ceramics via Ultrasonic Spray-Pyrolysis Route and their Material Properties

Yokota

Ito

Shimizu

et al. 2017

KEM

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Biological apatite presented in bone and teeth of mammals contains various ions in trace levels. Substitution of the ions into hydroxyapatite (HAp) can ensure higher bioactivity compared with stoichiometric HAp. It is known that sodium (Na) has been detected as an abundant trace element next to the presence of calcium and phosphorous in natural bone. The aim of this study is to examine the effect of substitution of Na on material properties of the HAp ceramics. Therefore, we have synthesized the sodium-substituted hydroxyapatite (NaAp) ceramics without carbonate ions by an ultrasonic spray-pyrolysis (USSP) technique. The USSP technique can obtain the desired powder by directly heating droplets of a sample solution with the target composition. Both NaAp powders with (Ca+Na)/P ratios of 1.67, 1.72 and 1.77 and their ceramics did not contain carbonate ions, and HAp single phase was maintained even after sintering. It was revealed that the substitution of Na enhanced the sinterability of HAp ceramics and improved the apatite-forming ability.

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Characterization of Various Apatites Powders Prepared by Ultrasonic Spray-Pyrolysis Technique

Abstract: Various apatites powders with the formula of Mio(PO4)6(OH)2 (M=Mg,

Cited by 10 publications

References 2 publications

Preparation of Calcium-Phosphate Microspheres by Salt-Assisted Ultrasonic Spray-Pyrolysis Technique and their Drug Release Behavior Using Anti-Angiogenic Agent, TNP-470

Preparation of Calcium-Phosphate Microspheres by Salt-Assisted Ultrasonic Spray-Pyrolysis Technique and their Drug Release Behavior Using Anti-Angiogenic Agent, TNP-470

Novel chemoembolization using calcium‐phosphate ceramic microsphere incorporating TNP‐470, an anti‐angiogenic agent

Fabrication of Sodium-Substituted Hydroxyapatite Ceramics via Ultrasonic Spray-Pyrolysis Route and their Material Properties

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