scholarly journals Fabrication of Carbonate Apatite Block through a Dissolution–Precipitation Reaction Using Calcium Hydrogen Phosphate Dihydrate Block as a Precursor

Materials ◽  
2017 ◽  
Vol 10 (4) ◽  
pp. 374 ◽  
Author(s):  
Kanji Tsuru ◽  
Ayami Yoshimoto ◽  
Masayuki Kanazawa ◽  
Yuki Sugiura ◽  
Yasuharu Nakashima ◽  
...  
Keyword(s):  
Precipitation Reaction ◽  
Carbonate Apatite ◽  
Hydrogen Phosphate ◽  
Phosphate Dihydrate

Effects of pH on the Transformation of Gypsum to Carbonate Apatite in the Presence of Ammonium Hydrogen Phosphate

2006 ◽  
Vol 309-311 ◽  
pp. 199-202 ◽  
Author(s):  
Ishikawa Kunio ◽  
Yumiko Suzuki ◽  
Shigeki Matsuya ◽  
Masaharu Nakagawa ◽  
Kiyoshi Koyano
Keyword(s):  
The Other ◽  
Dicalcium Phosphate ◽  
Carbonate Apatite ◽  
Compositional Change ◽  
Hydrogen Phosphate ◽  
Detailed Mechanism ◽  
Effects Of Ph ◽  
Ammonium Hydrogen ◽  
Ammonium Hydrogen Phosphate ◽  
Ph Dependent

Effects of pH on the transformation of gypsum to apatite in the presence of ammonium hydrogen phosphate was studied using NH4H2PO4, (NH4)2HPO4 and (NH4)3PO4. When set gypsum was immersed to ammonium hydrogen phosphate, pH of the solution decreased regardless of the solution. Although pH of the solution decreased, no significant compositional change was observed when gypsum was immersed in NH4H2PO4. On the other hand, apatite and small amount of dicalcium phosphate anhydrous (CaHPO4) was formed when gypsum was immersed in (NH4)2HPO4 solution. Only apatite was formed when gypsum was immersed in (NH4)3PO4 solution. Although the detailed mechanism for the pH dependent products has not been clarified, one of the causes may be the different thermodynamical difference between gypsum and apatite. We would like to recommend the use of (NH4)3PO4 solution since this provides higher pH and thus larger thermodynamical difference between apatite and gypsum and resulting pure apatite block.

scholarly journals Preparation and evaluation of an ispaghula based directly compressible matrixing agent for controlled release

2008 ◽  
Vol 58 (3) ◽  
pp. 309-316 ◽  
Author(s):  
Anita Lalwani ◽  
Jolly Parikh
Keyword(s):  
Controlled Release ◽  
Hydroxypropyl Methylcellulose ◽  
Hydrogen Phosphate ◽  
Lattice Design ◽  
Phosphate Dihydrate ◽  
Simplex Lattice Design ◽  
Dependent Variables ◽  
Simplex Lattice ◽  
Preparation And Evaluation

Preparation and evaluation of an ispaghula based directly compressible matrixing agent for controlled releaseThe objective of the present investigation was to prepare and evaluate an ispaghula husk based directly compressible (DC) adjuvant that can be used as matrixing agent using an agglomeration technique. Addition of hydroxypropyl methylcellulose was found necessary to improve cohesion. Lactose (X1), calcium hydrogen phosphate dihydrate (X2) and Avicel PH101 (X3), used along with ispaghula in preparation of agglomerates, were selected as three independent variables in a simplex lattice design affecting compressional and dissolution characteristics of the drug from the DC adjuvant. The agglomerates were evaluated for their flow properties. Tablets were prepared using 70% agglomerates and 30% acetaminophen, a poorly compressible drug, and were subjected toin vitrodrug release study. Amounts of the drug released at the end of 60 min (Y60), 300 min (Y300) and 480 min (Y480) were selected as dependent variables in a simplex lattice design. Batch IH05 that contained lactose and calcium hydrogen phosphate dihydrate in a 1:2 ratio could control the release for 12 hours and thus form the basis for twice a-day-dosing.

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