Calcium Hydrogen Phosphate Dihydrate Research Articles

Evaluation of carbonate apatite blocks fabricated from dicalcium phosphate dihydrate blocks for reconstruction of rabbit femoral and tibial defects.

This study aimed to evaluate in vivo behavior of a carbonate apatite (CO3Ap) block fabricated by compositional transformation via a dissolution-precipitation reaction using a calcium hydrogen phosphate dihydrate [DCPD: CaHPO4·2H2O] block as a precursor. These blocks were used to reconstruct defects in the femur and tibia of rabbits, using sintered dense hydroxyapatite (HAp) blocks as the control. Both the CO3Ap and HAp blocks showed excellent tissue response and good osteoconductivity. HAp block maintained its structure even after 24 weeks of implantation, so no bone replacement of the implant was observed throughout the post-implantation period in either femoral or tibial bone defects. In contrast, CO3Ap was resorbed with increasing time after implantation and replaced with new bone. The CO3Ap block was resorbed approximately twice as fast at the metaphysis of the proximal tibia than at the epiphysis of the distal femur. The CO3Ap block was resorbed at an approximately linear change over time, with complete resorption was estimated by extrapolation of data at approximately 1-1.5 years. Hence, the CO3Ap block fabricated in this study has potential value as an ideal artificial bone substitute because of its resorption and subsequent replacement by bone.

Application of synthetic and semisynthetic polymers (Kollidon K30 and hydroxypropylmethylcellulose) as carriers of ketoprofen in solid oral prolonged-release dosage forms

One of the most important challenges of the modern technology of solid oral dosage forms is to increase the effectiveness of the drug, reduce side effects and improve the comfort of use. One way to obtain such effects are prolonged release dosage forms. The aim of the study was to investigate the suitability of polymers (synthetic - Kollidon K30 and semisynthetic - hydroxypropyl methylcellulose), and calcium hydrogen phosphate dihydrate - as an inorganic insoluble filler - in the construction of the matrices of the solid oral dosage forms containing non-steroidal anti-inflammatory drugs (NSAIDs). We used ketoprofen as a model active ingredient. Ketoprofenum, hydroxypropylmethylcellulose, calcium hydrogen phosphate, kollidon K30, magnesium stearate. Incorporation. Studies of the tablet mass. Direct tabletting. Studies of the pharmacopoeial parameters and pharmaceutical availability. Measurements of the viscosity of 1% solution of HPMC and Kollidon K30. Approximation of the results. We obtained three versions (formulations) of the matrices. The results of the granulometric research on tablet formulations were consistent with the standards. The results of morphological studies and pharmacopoeial tablets were consistent with the standards. The best results were obtained for the release formulations containing HPMC and calcium hydrogenphoshate. Kollidon K30 accelerated the release of ketoprofen from tablets of formulation I. The model system of preformulation studies showed the usefulness of HPMC and Kollidon K30 in the technology of hydrophilic matrices with ketoprofen.

Fabrication of Carbonate Apatite Block through a Dissolution-Precipitation Reaction Using Calcium Hydrogen Phosphate Dihydrate Block as a Precursor.

Carbonate apatite (CO3Ap) block, which is a bone replacement used to repair defects, was fabricated through a dissolution–precipitation reaction using a calcium hydrogen phosphate dihydrate (DCPD) block as a precursor. When the DCPD block was immersed in NaHCO3 or Na2CO3 solution at 80 °C, DCPD converted to CO3Ap within 3 days. β-Tricalcium phosphate was formed as an intermediate phase, and it was completely converted to CO3Ap within 2 weeks when the DCPD block was immersed in Na2CO3 solution. Although the crystal structures of the DCPD and CO3Ap blocks were different, the macroscopic structure was maintained during the compositional transformation through the dissolution–precipitation reaction. CO3Ap block fabricated in NaHCO3 or Na2CO3 solution contained 12.9 and 15.8 wt % carbonate, respectively. The diametral tensile strength of the CO3Ap block was 2 MPa, and the porosity was approximately 57% regardless of the carbonate solution. DCPD is a useful precursor for the fabrication of CO3Ap block.

Dissolution studies in few urinary type crystals

Kidney stones are hard, solid particles that form in the urinary tract. The stones were very small and can pass out of the body without any problems. Calcium containing stone, especially Calcium Oxalate Monohydrate, Calcium Oxalate Di- hydrate and basic Calcium Phosphate, Calcium Hydrogen Phosphate Di-hydrate, Struvite and are the most commonly occurring stones. Calcium Oxalate Monohydrate crystals are grown in single diffusion gel growth technique. The grown crystals are characterized by FTIR, XRD and inhibition studies. A number of medicinal plants were antiurolithiatic activity such as Tribulus terrestriis and Boerhaavia diffusa Linn were carried out. Calcium Oxalate Monohydrate crystals in the presence of the herbal extract of one of the medicinal plants Tribulus terrestris Linn. The results are discussed.

The Ternary System H3PO4– Ca(OH)2–H2O Isotherms at 15 and 45 °C

The solid–liquid phase equilibria of the system H 3 PO 4 – Ca(OH) 2 –H 2 O were studied under air pressure using a synthetic method based on conductivity measurements. Two isotherms at 15 and 45 °C were completely defined. The stable solid phases which appear in this range of temperature are hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ), calcium hydrogen phosphate dihydrate (CaHPO 4 .2H 2 O), calcium hydrogen phosphate anhydrous (CaHPO 4 ) and calcium dihydrogen phosphate monohydrate (Ca(H 2 PO 4 ) 2 .H 2 O). These solid phases were characterized using X ray diffraction.

The Ternary System H3PO4-Ca(OH)2-H2O Isotherms at 15 and 45 °C

The solid–iquid phase equilibria of the system H3PO4–Ca(OH)2–H2O were studied under air pressure using a synthetic method based on conductivity measurements. Two isotherms at 15 and 45 °C were completely defined. The stable solid phases which appear in this range of temperature are hydroxyapatite (Ca10(PO4)6(OH)2), calcium hydrogen phosphate dihydrate (CaHPO4.2H2O), calcium hydrogen phosphate anhydrous (CaHPO4) and calcium dihydrogen phosphate monohydrate (Ca(H2PO4)2.H2O). These solid phases were characterized using X ray diffraction.

Identification of mineral compositions in some renal calculi by FT Raman and IR spectral analysis

We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500–400cm−1) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH.

Induction of nano-surface structure on the DCPD particles (Calcium hydrogenphosphate dihydrate)

Induction of nano-surface structure on the DCPD particles (Calcium hydrogenphosphate dihydrate)

Synthesis of β-Tricalcalcium Phosphate Block by Wet Milling Method of Calcium Hydrogen Phosphate Dihydrate and Calcium Carbonate

Synthesis of β-TCP block by wet milling method of calcium hydrogen phosphate dihydrate (CaHPO4Ÿ2H2O) and calcium carbonate (CaCO3) was evaluated. Uniaxially pressed block at 5, 10 and 15 MPa of mixture CaHPO4Ÿ2H2O and CaCO3 were sintered at 1000°C, 1050°C and 1100°C. XRD analysis revealed that single phase β-TCP was obtained at all press pressure and sintering temperature. The crystallinity and crystallite size of the obtained β-TCP increased with increasing press pressure and sintering temperature.

Fluconazole–excipient compatibility studies as the first step in the development of a formulation candidate for biowaiver

The biowaiver of bioequivalence studies on class I drugs of the biopharmaceutics classification system (BCS) is aimed mainly at reducing the costs and the exposure of health volunteers to a new pharmaceutical formulation. Fluconazole is an important antifungal agent but in the literature it is not clear whether it belongs to BCS class I or III. Compatibility studies are considered to be the first step in product development and on considering a biowaiver candidate these gain even greater importance since the final product will not be submitted to in vivo tests. The aim of this study was to qualitatively determine the composition of a commercially available fluconazole formulation in the form of capsules with regard to the presence of critical excipients and to carry out compatibility studies by differential scanning calorimetry (DSC). One formulation did not contain sodium lauryl sulfate and contained mannitol, in contrast to the reference formulation, which could hinder the acceptance of the biowaiver. The interaction of fluconazole with microcrystalline cellulose and calcium hydrogen phosphate dihydrate was observed; however, no indication of incompatibility was found in the DSC analysis of the commercial pharmaceutical formulations. These interactions were also studied by Fourier transform infrared spectroscopy, where small changes in the bands were observed, and by X-ray Powder diffraction and scanning electron microscopy that did not evidence any modification in the solid state characteristics.

ChemInform Abstract: Why Is Mannitol Becoming More and More Popular as a Pharmaceutical Excipient in Solid Dosage Forms?

AbstractReview: 42 refs.

In situ synthesis of calcium phosphates on chitosan macromolecules in the presence of glutamic and aspartic acids

Calcium hydrogen phosphate dihydrate and amorphous calcium phosphate have been synthesized in an aqueous suspension of medium molecular weight chitosan in the presence of glutamic or aspartic acid. X-ray diffraction and transmission and scanning electron microscopy characterization showed that the morphology of the phases present depended on the nature of the amino acid. The amino acids participate in the protonation of the amino groups of the chitosan and, probably, in the formation of chelate intermediate compounds with calcium ions, which act as calcium phosphate nucleation centers.

Magnetically Induced Crystal Alignment of Calcium Hydrogen Phosphate Dihydrate

Calcium hydrogen phosphate dihydrate is a precursor material of hydroxylapatite; the mineral phase of calcified tissues, and is a biomaterial that is known to show high biocompatibility and resorbability in-vivo. It exhibits anisotropic growth and dissolution behaviors, and quite recently, its conversion kinetics into hydroxylapatite has been reported to alter on coatings with distinct crystal alignments. These imply that biological behaviors of polycrystalline calcium hydrogen phosphate dihydrate are affected by crystal alignment. Meanwhile, an intense magnetic field is a useful tool to induce crystal alignment in various nonmagnetic substances. In this study, the possibility to control crystal alignment of polycrystalline calcium hydrogen phosphate dihydrate using a magnetic field has been investigated. Calcium hydrogen phosphate dihydrate powder having plate-like morphology was synthesized and then its deflocculated suspension was consolidated under a magnetic field of up to 3 T. X-ray diffraction measurements showed that the intensity ratio of (121) against (020) increased on the surface perpendicular to the magnetic field with intensifying the magnetic field strength. Under a 3 T magnetic field, high alignment against (121) plane has been observed which is unfamiliar for calcium hydrogen phosphate dihydrate. The results indicate that a magnetic field successfully induced crystal alignment in polycrystalline calcium hydrogen phosphate dihydrate.

Growth and Characterization of Agar Gel Grown Brushite Crystals

Brushite [CaHPO4·2H2O] or calcium hydrogen phosphate dihydrate (CHPD) also known as urinary crystal is a stable form of calcium phosphate. The brushite crystals were grown by single and double diffusion techniques in agar-agar gel at room temperature. Effects of different growth parameters were discussed in single diffusion and double diffusion techniques. Good quality star, needle, platy, rectangular, and prismatic shaped crystals in single diffusion and nuclei with dendritic growth were obtained in double diffusion. These grown nuclei were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). SEM has shown the different morphologies of crystals; FTIR has confirmed the presence of functional groups; crystalline nature was supported by XRD, whereas the TGA indicates total 24.68% loss in weight and formation of stable calcium pyrophosphate (Ca2P2O7) at 500°C.

Reaction of sea shells with resemble phosphorus wastewater and application of products

The removal and reuse of phosphorus is necessary to resolve environmental problems. The recovery of rare earth elements is also required for the sustainable developments. The aim of this work is to solve above two problems. In this work, we tried to remove phosphorus from wastewater with corbicula shell and Japanese littleneck shells. The obtained by-product was also used to recover rare earth cations. The chemical composition of by-products was investigated by ICP, XRD analyses, and SEM images. The main composition of the precipitates was calcium hydrogen phosphate di-hydrate, CaHPO4•2H2O. These calcium phosphates recovered the rare earth cations. Samples synthesized from seashells had small difference on the recovery of rare earth elements with samples synthesized from commercial calcium carbonate.

Dielectric Property Studies of Biologically Compatible Brushite Single Crystals Used as Bone Graft Substitute

The electrical characterization of bone is essential for the better understanding of the role of electrical stimulation in bone remodeling. Calcium Hydrogen Phosphate Dihydrate or brushite (CaHPO4 2H2O) has been used in bone substitution owing to their fast resorption under physiological condition. Brushite is a suitable matrix for osteoconductive bone grafts. In this work, Calcium Hydrogen Phosphate single crystals have been grown by single diffusion gel growth technique. The powder XRD studies revealed the monoclinic structure of the grown crystals. The vibrational analysis of the crystals is done with FTIR spectroscopy and the major functional groups and their assigned vibrations are discussed. The frequency dependence of dielectric constant and ac conductivity at different temperatures have been studied in detail. This study shows decrease in the dielectric constant with the increase in frequency and temperature. The variation of ac conductivity is found to be increasing with frequency and decreasing with temperature.

Urinary stone formation: Efficacy of seed extract of Ensete superbum (Roxb.) Cheesman on growth inhibition of calcium hydrogen phosphate dihydrate crystals

The effect of aqueous seed extract of Ensete superbum (Roxb.) Cheesman on in vitro crystallization and growth patterns of calcium hydrogen phosphate dihydrate (CaHPO4·2H2O, CHPD) crystals was studied using single diffusion gel growth technique. Reduction in growth of CHPD crystals was noticed with increasing concentrations of seed extract. The morphology of CHPD or brushite crystals was studied by microscopy. The structural changes of the treated crystals were assessed by SEM, FT-IR, XRD and TGA/DTA analysis. It is expected that this multidisciplinary approach for in vitro crystallization and characterization of CHPD crystals will provide a better explanation to develop novel strategies for prevention of urinary stones.

Preparation and in vivo evaluation of immediate-release pellet containing celecoxib solid dispersion

The aim of this study was to make use of small size of immediate-release (IR) pellet and amorphous state of solid dispersion to increase solubility of celecoxib (CLX), a drug in BCS class II. Primary, binary and ternary solid dispersions were developed to choose the final components for solid dispersion. A ternary novel solid dispersion was prepared by incorporation of one aqueous soluble polymer (povidone k17; PVP 17PF), Methacrylate copolymer-based gastric soluble polymer (Eudragit® EPO) and one pH modulator (MgO). This combination was effective to increase solubility in pH 1.2 up to 25–30 %. The mechanism of solubility enhancement was proven by DSC, PRXD, and FT-IR. Accordingly, hydrogen bonding or electrostatic interaction of CLX with PVP/Eudragit® EPO was the main cause to form the amorphous state of CLX within polymer cluster which increasing solubility of drug. Besides, MgO played an important role to change microenviroment for solid dispersion. Pellets containing this solid dispersion were prepared by extrusion and spheronization technique. Effect of four kinds of additive (calcium hydrogen phosphate dihydrate, NaHCO3, crospovidone, and sodium dodecyl sulfate) on dissolution of CLX from IR pellet was also determined. Because of highest dissolution rate, formulation using sodium dodecyl sulfate was used for pharmacokinetics study. Solid dispersion-IR pellet formulation presented bioequivalence and lower variability in comparison with reference product.

Silicone intraocular lens surface calcification in a patient with asteroid hyalosis

To confirm a substance presence on the posterior intraocular lens (IOL) surface in a patient with asteroid hyalosis. An 80-year-old man had IOLs for approximately 12 years. Opacities and neodymium-doped yttrium aluminum garnet pits were observed on the posterior surface of the right IOL. Asteroid hyalosis and an epiretinal membrane were observed OD. An IOL exchange was performed on 24 March 2008, and the explanted IOL was analyzed using a light microscope and a transmission electron microscope with a scanning electron micrograph and an energy-dispersive X-ray spectrometer for elemental analysis. To confirm asteroid hyalosis, asteroid bodies were examined with the ionic liquid (EtMeIm+ BF4-) method using a field emission scanning electron microscope (FE-SEM) with digital beam control RGB mapping. X-ray spectrometry of the deposits revealed high calcium and phosphorus peaks. Spectrometry revealed that the posterior IOL surface opacity was due to a calcium-phosphorus compound. Examination of the asteroid bodies using FE-SEM with digital beam control RGB mapping confirmed calcium and phosphorus as the main components. Calcium hydrogen phosphate dihydrate deposits were probably responsible for the posterior IOL surface opacity. Furthermore, analysis of the asteroid bodies demonstrated that calcium and phosphorus were its main components.

Chemisorption properties of calcium hydrogen phosphate with respect to Cu(II) and Zn(II) ions in mono- and bicomponent solutions

Chemisorption properties of calcium hydrogen phosphate dihydrate CaHPO4·2H2O with respect to Cu(II) and Zn(II) ions in Me(NO3)2 mono- and bicomponent solutions were considered.