Diluents calcium phosphate

Diluents calcium phosphate, calcium hydrogen phosphate, calcium sulphate, glucose, kaolin, lactose, mannitol, colloidal silica, sodium chloride sodium sulphate, sorbitol. 

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. 

Native starches are used as disintegrants, diluents, and wet binders. However, their poor flow and high lubricant sensitivity make them less favorable in direct compression. Different chemical, mechanical, and physical modifications of native starches have been used to improve both their direct compression and controlled-release properties (Sanghvi, 1993 van Aerde and Remon, 1988). Schinzinger and Schmidt (2005) used potato starch as an excipient and compared its granulating behavior with a-lactose-monohydrate and di-calcium phosphate anhydrous in a laboratory fluidized bed granulator using statistical methods. 

MCC, lactose, calcium phosphate dibasic, and mannitol were selected as common tableting diluents and were evaluated as received from their vendors. These materials are summarized in Table 2. Each material is available from several vendors with multiple grades. Three grades within each excipient were selected for their diverse range of physical and mechanical properties (3). These materials typically comprise 5% to 70% of a formulation. The samples were stored at environmentally controlled laboratory conditions of 20 2°C and 40% 10% relative humidity. 

Calcium phosphate dibasic dihydrate (diluent) 21% w/w as di hydrate water Decomposes below 100°C with loss of water 7.4 Practically insoluble in water 19%w/w... 

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. 

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]. 

Tablet diluent Inert substance used as filler to create desired bulk, flow properties, and compression characteristics in preparation of tablets Dibasic calcium phosphate, kaolin, lactose, mannitol, microcrystalline cellulose, powdered cellulose, precipitated calcim carbonate, sorbitol, starch...

Probably the second most commonly used diluent in the wet granulation process is dibasic calcium phosphate. This substance is virtually insoluble in water and hence is always used in conjunction with a disintegrating agent. Its properties have been reviewed by Carstensen and Ertell. ... 

The most widely used inorganic direct compression diluent is calcium phosphate. It is available in several forms, but the immilled (i.e., coarse) dibasic dihydrate (CaHP04 2H2O) is the most frequently used. It has good flow and binding properties. Consolidation is... 

Bryan J W, McCallister JD. Matrix forming capabilities of three calcium diluents. Drug Dev Ind Pharm 1992 18(19) 2029—2047. Carstensen JT, Ertell C. Physical and chemical properties of calcium phosphates for solid state pharmaceutical formulations. Drug Dev Ind Pharm 1990 16(7) 1121-1133. 

Tribasic calcium phosphate is widely used as a capsule diluent and tablet filler/binder in either direct-compression or wet-granulation processes. The primary bonding mechanism in compaction is plastic deformation. As with dibasic calcium phosphate, a lubricant and a disintegrant should usually be incorporated in capsule or tablet formulations that include tribasic calcium phosphate. In some cases tribasic calcium phosphate has been used as a disintegrant. It is most widely used in vitamin and mineral preparations as a filler and as a binder. It is a source of both calcium and phosphorus, the two main osteogenic minerals for bone health. The bioavailability of the calcium is well known to be improved by the presence of cholecalciferol. Recent research reports that combinations of tribasic calcium phosphate and vitamin D3 are a cost-effective advance in bone fracture prevention. ... 

Therefore, if when carrying out a preformulation study we wished to compare the effects of 4 diluents (e.g. lactose, calcium phosphate, microcrystalline cellulose, and mannitol), 3 disintegrants, 2 binders, 2 lubricants, and a glidant (e.g. presence or absence of colloidal silica), it is easy to verify that the model contains 14 coefficients (including the constant term), but only 9 of these are independent. 

Experimental designs to establish the effect of the composition of a mixture on its properties differ from other designs in that the initial parameters are not usually independent of one another. The properties of a mixture of three diluents, lactose, calcium phosphate and microcrystalline cellulose, for example, may be defined in terms of the percentage of each component. If we know the concentration of the first two components we can automatically find the concentration of the third. This non-independence of the variables means that designs of the type outlined above are unsuitable for many problems involving mixtures. However the classical designs may be used in two circumstances - for the choice of excipients, where the factors are purely qualitative, and also in problems where the proportions of all but one of the excipients are constrained to be relatively small. 

Diluent lactose microcrystalline cellulose (M.C.C.) corn starch calcium phosphate dihydrate mannitol (see experimental design, table 9.10) 91%... 

We call the class of component (e.g. diluent) the mqjor, or M-component. Each member of that class (lactose, cellulose, calcium phosphate) is a minor component (m-component). Instead of there being individual restrictions on each excipient, L, < x, < t/ let there be an overall restriction on the class. So if there are three polymers in a sustained release formulation, X, Xj, Xj j 3, we may, in optimizing the composition, fix the total amount of polymer between 10 and 25%, but allow the individual polymers to vary freely within that range. Therefore ... 

Dicalcium phosphate (anhydrous or sometimes as the dihydrate) has many uses. These include glass manufacture, plastics stabilisation, fertilisers and animal feeds. In addition, it is used as a dough additive, a nutrient and a dietary supplement. In pharmacy, it is used as a tablet diluent and dispersant calcium phosphates have other medical applications [32]. Other uses include paint and pigments and in toothpaste as a secondary abrasive. 

The primary use for dibasic calcium phosphate in pharmaceutical applications is as a tablet or capsule diluent. It is also used as an excipient for direct compression formulations of hard tablets requiring a good disintegrant and an effective lubricant. It has limited use as a mineral supplement for calcium replenishment. Diluents often comprise the bulk of the tablet formulation, with use levels between 40 to 90 % of the tablet weight. It has also foimd use as an adsorbent and as a thickening agent in creams and ointments. The pharmacopeial specifications for Dibasic Calcimn Phosphate USP are as follows ... 

Tribasic calcium phosphate is soluble in dilute mineral aeids, very slightly soluble in water, and insoluble in aleohol. It is used in the pharmaceutical industry primarily as a tablet and eapsule diluent and as a flow and non-caking agent. Tribasic calcium phosphate provides a higher calcium load than dibasic calcium phosphate. It should not be used with strong acidie salts of weak organic bases or in the presenee of acetate salts. It influences the adsorption of vitamin D, and should not be used with water soluble B vitamins or with certain esters sueh as vitamin E or vitamin A acetate or palmitate. It forms a ealeium eomplex with tetracycline. A tablet formulation utilizing triealeium phosphate as a filler is shown below. 

Miscellaneous. Both whiting and hydrated lime are used as diluents and carriers of pesticides, such as lime—sulfur sprays, Bordeaux, calcium arsenate, etc. The most widely used bleach and sterilizer, high test calcium hypochlorite, is made by interacting lime and chlorine (see Bleaching AGENTS). Calcium and magnesium salts, such as dicalcium phosphate, magnesium chloride, lithium salts, etc, are made directly from calcific and dolomitic lime and limestone. 

Calcium hypochlorite is the principal commercial soHd hypochlorite it is produced on a large scale and marketed as a 65—70% product containing sodium chloride and water as the main diluents. A product with a significantly higher available chlorine, av CI2, (75—80%) has been introduced by Olin. Calcium hypochlorite is also manufactured to a smaller extent as a hemibasic compound (- 60% av Cl ) and to a lesser extent in the form of bleaching powder (- 35% av CI2). Lithium hypochlorite is produced on a small scale and is sold as a 35% assay product for specialty appHcations. Small amounts of NaOCl ate employed in the manufacture of crystalline chlorinated ttisodium phosphate [56802-99-4]. 

The polysulfide base material contains 50—80% of the polyfunctional mercaptan, which is a clear, amber, sympy Hquid polymer with a viscosity at 25°C of 35, 000 Pa-s(= cP), an average mol wt of 4000, a pH range of 6—8, and a ntild, characteristic mercaptan odor. Fillers are added to extend, reinforce, harden, and color the base. They may iaclude siUca, calcium sulfate, ziac oxide, ziac sulfide [1314-98-3] alumina, titanium dioxide [13463-67-7] and calcium carbonate. The high shear strength of the Hquid polymer makes the compositions difficult to mix. The addition of limited amounts of diluents improves the mix without reduciag the set-mbber characteristics unduly, eg, dibutyl phthalate [84-74-2], tricresyl phosphate [1330-78-5], and tributyl citrate [77-94-1]. 

The straight-chain 1- and 2-butenes are preheated to 600°C in a furnace, mixed with steam as a diluent to minimize carbon formation, and passed through a 5-m-diameter reactor with a bed of iron oxide pellets (or calcium nickel phosphate) 90 to 120 cm deep (contact time 0.2 second) at 620 to 750°C. The material is cooled and purified by fractional distillation and extraction with solvents such as furfural, acetonitrile, dimethylformamide (DMF), and N-mcthyIpyro11idonc (NMP) (Fig. 2). 

Another option to contribute phosphate to a fertilizer formulation is to use phosphoric instead of sulfuric acid for initial acidulation of phosphate rock. In this way the only solid product of acidulation is the soluble calcium dihydrogen phosphate free of gypsum diluent product with about three times the available P2O5 of superphosphate (Eq. 11.64). 

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