Calcium phosphate, dibasic

Figure 3. Interaction among pH, calcium, and phosphate in hyperalimentation solutions. The pH, calcium values to the right of phosphate isoconcentration curves are associated with precipitation of dibasic calcium phosphate, while pH, calcium values to the left of phosphate isoconcentration curves are associated with solubility of calcium and phosphates in hyperalimentation solution.

Dibasic Calcium Phosphate Dissolve 0.1 g in DW by the addition of 1 ml HC1. Perform the test with the solution. -do-... 

Dibasic calcium phosphate 0.2 g Hydroxy naphthol blue Each ml of 0.05 M disodium edetate = 0.002004 g of Ca... 

Patel et al. [40] found that moismre and the pH of the micro-environment influenced degradation the most. They identified the best diluent for tablet manufacture as being dibasic calcium phosphate, with a basic modifier (sodium carbonate, sodium bicarbonate or magnesium oxide). The authors indicated that the degradation pathways observed were deiodination, deamination and decarboxylation. The data are shown in Table 2.4. 

Dibasic calcium phosphate is found in nature as the mineral monetite. It is used as a food supplement and source of calcium, both in human food and ani-... 

Dibasic sodium phosphate also is prepared by reacting dibasic calcium phosphate with sodium carbonate. The product calcium carbonate precipitates leaving dibasic sodium salt in the solution. The solution on cooling yields... 

Z.T. Chowhan, The effect of low- and high-humidity ageing on the hardness, disintegration time and dissolution rate of dibasic calcium phosphate-based tablets. J. Pharm. Pharmacol., 32 (1980) 10. 

For methylcellulose, increased matrix material concentration did not affect the release profile (Table 4). The sustained action can be directly attributed to the formation of a hydration layer by this polymer. This hydration layer, however, did not resist attrition and remain intact. Consequently, attrition becomes more important than diffusion the hydrated layer dissolves away almost as rapidly as it is formed. On the contrary, the dibasic calcium phosphate dihydrate did not diffuse outward, but rather became entrapped within the matrix and effected an increase in release of drug because its presence necessarily decreased the polymer concentration. 

Dibasic Calcium Phosphate Dibenzo (B,E) Pyridine Dibenzoyl Peroxide DIBK... 

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. 

Excipients both typically contain water and are required to interact with it. The water associated with excipients can exist in various forms. Studies with different materials have shown that water can exist in association with excipients in at least four forms that may be termed free water, bound water, structural water, and water of crystallization. Water associated with a particular excipient may exist in more than one form (26). The type of water will govern how it is implicated in interactions between the excipient and the API or another excipient. The so-called free water is the form that is most frequently implicated in excipient interactions. Bound water is less easily available for interaction, and structural water is usually the least available one. Water of crystallization can be very tightly bound into the crystal structure however, there are some comparatively labile hydrates, e.g., dibasic calcium phosphate dihydrate (see above). If water of crystallization remains tightly bound within the crystal structure, it is unlikely to participate in an excipient interaction. However, any material that is in equilibrium with air above 0% RH will have some free moisture associated with it. In reality, below about 20% RH, the amount of moisture will probably be insufficient to cause problems. However, if sufficient moisture is present (e.g., at a higher RH), it can facilitate the interaction between components of the formulation. 

The dibasic calcium phosphate dihydrate example discussed above is probably an extreme example of the instability of an excipient relating to the release of water. But many excipients exist in a hydrated state, and heating them for the purposes of compatibility studies, or accelerated stability testing, can cause any free water, and sometimes other types of water, to be released, which can then influence any potential interaction, or even interact itself with the drug. 

Calcium Phosphate Dibasic (Dibasic Calcium Phosphate)... 

Figure 5 Scans of commonly used excipients for tablet manufacture. Key-MCC (Avicel PH101),—MCC (Avicel Ph200), Lactose (Foremost 325),—dibasic calcium phosphate (di-tab) and—Mg Stearate.

Dibasic calcium phosphate Tablet binder Sodium hydroxide Alkaline agent... 

Calcium supplements Calcium carbonate (BioCal, Os-Cal 500, Turns, others) Calcium citrate (Citracal) Calcium glubionate (Calcionate, Neo-Calglucon) Calcium gluconate Calcium lactate Dibasic calcium phosphate Tribasic calcium phosphate (Posture) Provide an additional source of calcium to prevent calcium depletion and encourage bone formation in conditions such as osteoporosis, osteomalacia, rickets, and hypoparathyroidism... 

Dibasic calcium phosphate (CaHP04) is manufactured from phosphoric acid and lime ... 

Catapres Clonidine HC1 USP 0.1, 0.2, 0.3 mg Tablet Hypertension Alpha-adrenoreceptor agonist Colloidal silicon dioxide, corn starch, dibasic calcium phosphate, gelatin, glycerin, lactose, magnesium stearate, methylparaben, propylparaben Boehriner Ingelheim (Mylan)... 

Diluents. In general, diluents make up most of the dosage form. The selection of diluents is very important, especially for low-dose formulations, since they may make up 85-95% of the granulation. These diluents may be soluble or insoluble. The most commonly used soluble fillers include lactose, mannitol and sucrose. Commonly used insoluble fillers include microcrystalline cellulose, starch, calcium sulfate, and dibasic calcium phosphate. 

There are many commercially available direct compression filler-binders. The most commonly used filler-binders include spray-dried lactose, mannitol, microcrystalline cellulose, pregelatinized starch, and dibasic calcium phosphate. Many factors affect the selection of a filler-binder for a direct compression tablet formulation. The most important requirements for a directly compressible filler-binder used in a low-dose formulation are listed below ... 

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... 

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

Modification of density Dibasic calcium phosphate Avicel PH101 Fujicalin Avicel PH301, Avicel PH302 Better blending behavior... 

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