Calcium phosphate precipitated

Synonyms calcium orthophosphate calcium phosphate tricalcium phosphate tertiary calcium phosphate precipitated calcium phosphate bone ash (technical product). 

Common suspending agents are poly(vinyl alcohols) of various molecular weights and degrees of hydrolysis, starches, gelatin, calcium phosphate (especially freshly precipitated calcium phosphate dispersed in water to be used in the preparation), salts of poly(acrylic acid), gum arabic, gum tragacanth, etc. 

Salvo, J. D., Schubert, M. Specific interaction of some cartilage proteinpolysaccharides with freshly precipitating calcium phosphate. J. Bio. Chem. 242, 705 (1967)... 

The primary purpose of phosphate addition is to precipitate the hardness constituents. The calcium reacts with phosphate under the proper pH conditions to precipitate calcium phosphate as calcium hydroxyapatite, Cain(P04)fi(0H)2. This is a flocculent precipitate that tends to be less adherent to boiler surfaces than simple tricalcium phosphate, which is... 

SS) West, V. C. Observations on phase transformation of a precipitated calcium phosphate. Calc. Tiss. Res. 7, 212-219 (1971). 

Tribasic calcium phosphate, Ca3P208, may be made by washing precipitated calcium phosphate with ammonia, which dissolves any excess of phosphoric acid above that required to form this compound. It is a white earthy powder which retains water tenaciously, and also adsorbs halides, bicarbonates and hydroxides.1 It has also been prepared from CaH4(P04)a by dissolving this in a large excess of water... 

Tricalcium Phosphate Precipitated Calcium Phosphate Calcium Hydroxyapatite... 

At pH values below about 6.0 the influence of HEDP and fluoride, an important environmental constituent is particularly interesting. It has been shown that the nature of the precipitating calcium phosphate phase can be controlled not only by the concentration of inoculating HAP seed ( )but also by the presence of additives. Thus fluoride ion accelerates the crystallization of calcium phosphate probably through the formation of fluorapatite (Ca5(P04)3 F, FAP) (, 60). Under... 

Phosphate i.v. is quickly effective but lowers calcium by precipitating calcium phosphate in bone and soft tissues and inhibiting osteoclastic activity it should be used only when other methods have failed. 

Precipitates Drugs prepared by separating particles from a previously clear liquid by physical or chemical means. Precipitation usually occurs when a hot saturated solution of an amorphous substance is allowed to cool or when a liquid in which the dissolved substance is insoluble is added to its solution. Pharmacists formerly used the process of precipitation as a convenient method of obtaining solid substances in fine particles (precipitated calcium carbonate), to purify solids (precipitated calcium phosphate), or to prepare mercury salts. White precipitate (ammoniated mercury) was first described by Beguin in 1632, a soluble double chloride of mercury and ammonium known to the alchemists as sal alembroth and sal sapientiae, respectively. Red precipitate (red mercuric oxide) was known to alchemists as hydragyrum preci-pitatum per se or precipitate per se yellow precipitate is a synonym for yellow mercuric oxide. " Preserves See Conserves. 

Calcium orthophosphate E341 hydroxylapatite phosphoric acid calcium salt (2 3) precipitated calcium phosphate tertiary calcium phosphate Tri-Cafos tricalcium diorthophosphate tricalcium orthophosphate tricalcium phosphate TRI-CAL WG-, TRI-TAB. 

PHEMA into an SBF solution. At the higher released citric acid concentrations, the formation of calcium citrate crystals can bring about a depletion of the calcium ion concentration in the SBF solution, so less calcium phosphate will precipitate onto the polymer. At lower citric acid concentrations, the inhibition effect of citrate anions on formation of calcium phosphates has been attributed to the complex equilibria between calcium, citrate and phosphate ions (27-29). Precipitated calcium phosphates may undergo dissolution via surface exchange between phosphate and citrate ions (calcium citrate is much more soluble than calcium phosphate). 

Oral sodium phosphate lowers plasma Ca concentrations and may offer short-term calcemic control of some patients with primary hyperparathyroidism who are awaiting surgery. However, the risk of precipitating calcium phosphate salts in soft tissues throughout the body is of concern. In light of satisfactory responses to other agents, administration of intravenous sodium phosphate is not recommended as a treatment for hypercalcemia. 

As blood calcium levels fall, PTH is released from the parathyroid gland and acts directly upon the kidney and bone as well as indirectly on the intestines. The renal actions of PTH, mostly mediated by cAHP, are summarized in Table I. These direct renal PTH actions, therefore, elevate blood calcium levels by enhancing calcium reabsorption and by lowering blood phosphate concentrations and pH. The latter two actions of PTH allow calcium levels to rise to a greater extent without precipitating calcium phosphate. 

Synonyms Calcium phosphate tribasic Precipitated calcium phosphate Tricalcium phosphate... 

Synonyms Calcium orthophosphate Calcium phosphate tertiary Phosphoric acid, calcium salt (2 3) Precipitated calcium phosphate TCP Tertiary calcium phosphate Tribasic calcium phosphate Tricalcium bis (orthophosphate) Tricalcium orthophosphate Tricalcium phosphate... 

Precipitated calcium phosphate. See Calcium hydroxide phosphate Calcium phosphate tri basic... 

Phosphoric acid is used in sugar processing where it is added to raw sugar solutions. Addition of lime precipitates calcium phosphate which carries with it other impurities. 

There have been attempts to develop aquasomes as an alternative to liposomes for drug delivery. They consist of porous nanoparticles, specially prepared by sonication of precipitated calcium phosphates such as hydroxyapatite or dicalcium phosphate. These particles are then coated with oligomeric molecules containing -OH groups which can anchor an outer layer of drug molecules or other bioactive species. The outer layer of molecules becomes immobilised or stabilised during transportation to the required site for action. Aquasomes may serve to construct anti-viral decoys which act as vaccines. 

Calcification involves the seeding of the calcium apatite crystal and the growth of the crystals. It would be more convenient to review the second of these mechanisms first. This can best be done by assuming for the moment that the bone matrix, connective or cartilaginous, is bathed in a medium supersaturated in calcium phosphate. Intrinsic to the matrix, there is a mechanism that precipitates calcium phosphate in the form of tiny apatite crystals. If there is no interference with the process of calcification, either by deficient absorption of calcium (vitamin D deficiency) or by active dissolution of the calcium crystals (parathormone), most of the process of mineralization can probably be explained by the physicochemical properties of the apatite crystals. Thus, the divalent cations and anions, PO4 and calcium, penetrate the hydration shell reaching the surface of the crystals where they are crystallized, thereby increasing the size of the crystals. As mineralization proceeds, the amount of bound... 

The seeding of the apatite crystals triggers the entire mineralization process. All tissues are irrigated with a plasma supersaturated by calcium and phosphate. Yet crystallization occurs only in five different structures. Does the cartilage or the connective tissue of the bone contain specific molecules that precipitate calcium phosphate, or does the osteoblast secrete an enzyme that triggers crystallization In 1923, Robinson incubated slices of rachitic rat tibial epiphysis. 

Immersion or soaking is one of the simplest methods to incorporate calcium phosphate compounds into organic carriers (Figure 13.1(a)). The basic interaction between such precipitated calcium phosphate species and the organic compound is based on adhesion, in other words on ion-dipole interactions or van der Waals forces (dispersion forces) between the two major components. Hence, many studies include this simple processing step in their protocols [20,45,49]. 

Trade Names Hetoxol TDEP-15 PPS. See Pyridinium propyl sulfobetaine Precipitated barium sulfate. See Barium sulfate Precipitated calcium carbonate. See Calcium carbonate Precipitated calcium phosphate. See Calcium phosphate tribasic Precipitated chalk. See Calcium carbonate... 

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