Dibasic anhydrous calcium phosphate

In addition to the hydrate form, anhydrous dibasic calcium phosphate is also a directly compressible filler-binder. This form is also nonhygroscopic and stable at room temperature. 

Fujicalin is an anhydrous dibasic calcium phosphate designed as a direct compression excipient. It has improved flowability and compaction characteristics compared with the conventional product, and maintains the ability to rapidly disintegrate.50 Fujicalin s patented manufacturing process yields porous spheres with a... 

Anhydrous dibasic calcium phosphate and calcium triphosphate can also be used for direct compression. The latter is actually a mixture of calcium phosphates including tricalcium orthophosphate [Ca3(P04)2] and hydroxyapatite [Ca5(0H)(P04)3]. The preparation and properties of calcium phosphates have been reviewed by Carstensen and Ertell, and their tabletting properties have been studied by Bryan and McAllister. 

BP Anhydrous calcium hydrogen phosphate JP Anhydrous dibasic calcium phosphate PhEur Calcii hydrogenophosphas anhydricus USP Dibasic calcium phosphate... 

Anhydrous dibasic calcium phosphate is used both as an excipient and as a source of calcium in nutritional supplements. It is used particularly in the nutritional/health food sectors. It is also used in pharmaceutical products because of its compaction properties, and the good flow properties of the coarse-grade material.The predominant deformation mechanism of anhydrous dibasic calcium phosphate coarse-grade is brittle fracture and this reduces the strain-rate sensitivity of the material, thus allowing easier transition from the laboratory to production scale. However, unlike the dihydrate, anhydrous dibasic calcium phosphate when compacted at higher pressures can exhibit lamination and capping. This phenomenon can be observed when the material represents a substantial proportion of the formulation and is exacerbated by the use of deep concave tooling. This phenomenon also appears to be independent of rate of compaction. 

Anhydrous dibasic calcium phosphate is abrasive and a lubricant is required for tableting, for example 1% w/w magnesium stearate or 1 % w/w sodium stearyl fumarate. 

Two particle-size grades of anhydrous dibasic calcium phosphate are used in the pharmaceutical industry. Milled material is typically used in wet-granulated or roller-compacted formulations. The unmilled or coarse-grade material is typically used in direct-compression formulations. 

Anhydrous dibasic calcium phosphate is used in toothpaste and dentifrice formulations for its abrasive properties. 

Anhydrous dibasic calcium phosphate is a white, odorless, tasteless powder or crystalline solid. It occurs as triclinic crystals. 

The surface of milled anhydrous dibasic calcium phosphate is alkaline and consequently it should not be used with drugs that are sensitive to alkaline pH. However, reports suggest there are differences in the surface alkalinity/acidity between the milled and unmilled grades of anhydrous dibasic calcium phosphate the unmilled form has an acidic surface environment. This difference has important implications for drug stability, particularly when reformulating from, e.g. roller compaction to direct compression, when the particle size of the anhydrous dibasic calcium phosphate might be expected to change. 

Grades of anhydrous dibasic calcium phosphate available for direct compression include A-TAB (Rhodia), Di-Cafos AN (Chemische Fabrik Budenheim), Emcompress Anhydrous (JRS Pharma LP), and Fujicalin (Fuji Chemical Industry Co. Ltd.). The EINECS number for calcium phosphate is 231-837-1. 

Schlack H, Bauer-Brandl A, Schubert R, Becker D. Properties of Fujicalin, a new modified anhydrous dibasic calcium phosphate for direct compression comparison with dicalcium phosphate dihydrate. Drug Dev Ind Pharm 2001 27(8) 789-801. 

The stability of excipients is almost always taken for granted. Obviously, there is the potential for a phase change with certain lower melting excipients, e.g., semisolid materials, however, this is not a chemical phenomenon although it may enhance the potential for interaction by increasing the effective interface available at which the interaction can take place. However, some materials are not stable under conditions encountered in excipient compatibility screening or accelerated stability testing. A notable example is dibasic calcium phosphate dihydrate. At temperatures as low as 37°C, under certain conditions, the dihydrate can dehydrate to form the anhydrous material with the concomitant loss of water of crystallization (25), and at 25°C, it is a stable solid with a shelf life, when stored correctly, of more than two years. 

Property Fujicalin SG (Dibasic Calcium Phosphate, Dehydrate) Dibasic Calcium Phosphate, Dehydrate Dibasic Calcium Phosphate, Anhydrous... 

Diluents, although commonly presumed inert, do have the ability to influence the stability or bioavailability of the dosage form. For example, dibasic calcium phosphate (both anhydrous and dihydrate forms) is the most common inorganic salt used as a filler-binder for direct compression. It is particularly useful in vitamin products as a source of both calcium and phosphorous. Milled material is typically used in wet-granulated or roller-compacted formulations. The coarse-grade material is typically used in direct compression formulations. It is insoluble in water, but its surface is alkaline and it is therefore incompatible with drugs sensitive to alkaline pFI. Additionally, it may interfere with the absorption of tetracyclines [7]. 

Dibasic calcium phosphate dihydrate has been reported to be incompatible with a number of drugs and excipients and many of these incompatibilities are expected to occur with dibasic calcium phosphate, anhydrous see Calcium phosphate, dibasic dihydrate. 

Calcium phosphates are usually prepared by reacting very pure phosphoric acid with calcium hydroxide, Ca(OH)2 obtained from limestone, in stoichiometric ratio in aqueous suspension followed by drying at a temperature that will allow the correct hydration state to be achieved. After drying, the coarse-grade material is obtained by means of a classification unit the fine particle-size material is obtained by milling. Dibasic calcium phosphate, anhydrous, may also be prepared by spray-drying. " ... 

Dibasic calcium phosphate anhydrous is widely used in oral pharmaceutical products, food products, and toothpastes and is generally regarded as a relatively nontoxic and nonirritant material. 

Dibasic calcium phosphate anhydrous is a nonhygroscopic, relatively stable material. Under conditions of high humidity it does not hydrate to form the dihydrate. 

Takami K, Machimura H, Takado K, Inagaki M, Kawashima Y. Novel preparation of free-flowing spherically granulated dibasic calcium phosphate anhydrous for direct tabletting. Chem Pharm Bull 1996 44(4) 868-870. 

Accelerated stability studies carried out at elevated temperatures on formulations containing significant proportions of dibasic calcium phosphate dihydrate can give erroneous results owing to irreversible dehydration of the dihydrate to the anhydrous form. Depending on the type of packaging and whether or not the tablet is coated, the phenomenon can be observed at temperatures as low as 40°G after 6 weeks of storage. As the amount of dibasic calcium phosphate dihydrate in the tablet is reduced, the effect is less easy to observe. 

Calcium hydrogen orthophosphate Calcium hydrogen phosphate Calcium hydrogen phosphate anhydrous. See Calcium phosphate dibasic... 

Calcium cyanamide Calcium phosphate dibasic Calcium phosphate monobasic anhydrous Calcium phosphate monobasic monohydrate Calcium phosphate tribasic Calcium phosphite Cottonseed meal Dicyandiamide Dolomite Feldspar Ferric phosphate Ferrous sulfate anhydrous Ferrous sulfate heptahydrate Formaldehyde Kelp... 

Bis (4-(1,1-dimethylethyl) benzoato-o) hydroxy aluminum Cadmium stearate Calcium glycerophosphate Calcium phosphate dibasic Calcium phosphate monobasic anhydrous... 

Syntmyms (a) MCP Monocalcium Phosphate, Monohydrate Acid Calcium Phosphate, Calcium Superphosphate Calcium Biphosphate Primary Calcium Phosphate (b) DCP Dicalcium Phosphate (Anhydrous or Dihydrate) Dibasic Calcium Phosphate Calcium Monohydragen Phosphate Secondary Calcium Phosphate (c) TCP Calcium Phosphate Tribasic (d) Calcium Pyrophosphate Chemical Formula (a) CaH4(P04)2Hj0 (b) CaHP04 or... 

Dibasic Calcium Phosphate is a white odorless, tasteless powder or crystalline solid prepared from a phosphate mineral such as apatite. The apatite is dissolved in sulfuric acid and then filtered. The addition of calcium hydroxide precipitates dibasic calcium phosphate. The USP lists two types of calcium phosphate dibasic calcium phosphate, anhydrous, which has the empirical formula of CaHP04, and dibasic calcium phosphate dihydrate which has the empirical formula CaHP04 2H20. Synonyms for dibasic calcium phosphate include calcium hydrogen orthophosphate, dicalcium orthophosphate, and secondary calcium phosphate. 

---