Pentasodium Tripolyphosphate Research Articles

Quantitative Determination of Crystalline Na5P3O10 –I (Form-I) in Commercial Tripolyphosphate using X-ray Diffraction Patterns

An x-ray diffraction method (XRD) for quantitative determination of the crystalline Na5P3O10-I (Form-I) in a mixture of Form-I/Form-II was applied for commercial pentasodium tripolyphosphate analysis. The XRD pattern of the Form-I shows the unique non-overlapping 2θ peak at a position of ≈ 21.8 deg. and also at ≈ 29.0 deg. (Cu radiation). The area (integral of the intensity) under the peaks is proportional to the amount of the Form-I in the mixture covering the range up to 100 wt.%. That enables one to obtain a calibration line and to determine the amount of Form-I in the mixture of Form-I/Form-II and also in commercial pentasodium tripolyphosphate. Commercial samples with high Form-I concentration, in case they are contaminated with sodium pyrophosphate (Na4P2O7), should be diluted with Form-II to bring the concentration of the Form-I below 50 wt.% in the analysed sample.

Effect of preparation method on the capture and release of biologically active molecules in chitosan gel beads

AbstractModel bioactive compounds with different molecular and functional characteristics were entrapped in gel beads prepared by polyelectrolyte complexation of chitosan and pentasodium tripolyphosphate (TPP). Three compounds of interest to the food and biomedical industries were tested: (1) lysine, (2) bovine serum albumin (BSA), and (3) β‐galactosidase. Effects of the compound concentration in the initial chitosan solution, pH of the curing solution, and length of the curing phase on the capture efficiency were evaluated. Release rates for lysine and BSA into a phosphate buffer, distilled water, and a synthetic ocean solution were observed, and the activity of the entrapped β‐galactosidase was determined. The capture efficiencies for lysine and BSA decreased as the concentration increased. The capture efficiency for lysine ranged from 90% at pH 5 to 20% at pH 8.6. There was no significant effect of the release media on the rate of release. BSA and lysine release reached 90% of the maximum after 100 and 50 min, respectively. The capture efficiency of β‐galactosidase was not affected by the pH of TPP; however, enzyme activity in the beads decreased as the pH increased. Beads prepared in the pH 8.6 TPP solution had significantly higher rates of enzyme release over time. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 405–413, 2002; DOI 10.1002/app.10393

Density Functional Geometry Optimization and Energy Calculations of Calcium(II)-Triphosphate Complexes. Polyphosphates as Possible Dissolving Agents for Calcium Pyrophosphate Dihydrate Crystals in Chondrocalcinosis Disease

Geometry optimizations and energy calculations have been carried out via molecular orbital methods at the density functional B3LYP/LANL2DZ level on the molecules PO3 −, OPO3 3-, HOPO3 2-, CH3OPO3 2-, H(CH3OPO3 −, O(PO3)2 4-, HO(PO3)2 3-, CH2 (PO3)2 4-, (CH3OPO2)O(PO3)3-, O(PO3)3 5-, HO(PO3)3 4-, (PO3)3 3-, (CH3OPO2)O(PO3)2 3-, [Mg{O(PO3)2}]2-, [Ca{O(PO3)2}]2-, [Ca{CH2 (PO3)2}]2-, [Ca{CH3OPO2)O(PO3)}]−, [Ca(PO3)3]−, [Ca{O(PO3)3}]3-, and [Ca{CH3OPO2)O(PO3)2}]2- with the aim to find reliable and easily accessible computational methods to simulate some phosphate-containing molecules of importance for the living cells and to study the energetics for protonation and metal-complex formation reactions. The analysis is part of a general investigation on phosphate-containing molecules as potential dissolving agents for calcium pyrophosphate dihydrate (CPPD) crystals which deposit in certain articular diseases. The basis set was expanded to 6–31G** for the P atoms for all the molecules investigated and to 6–31G* for the O atoms for OPO3 3-. Calculations at the semi- empirical MNDO/d level were also carried out for comparison purposes on the free ligand molecules and on [Mg{O(PO3)2}]2-. The density functional analysis reproduced well the geometry found at the solid state via X-ray diffraction. The analyses of the geometrical parameters and the total electronic energy of the molecules shows that O(PO3)2 4- and other di- and tri-phosphates are versatile ligands for divalent metal ions like Ca2+. The computed P-O-P bond angle for free O(PO3)3 4- is 180° and the conformation of the two PO3 − groupings is staggered along the P…P vector. The linear arrangement for P-O-P is assisted by P-Oπ interactions. The bending of the P-O-P angle when accompanied by a slight P-O(b) elongation requires a very small amount of energy; 4.65 kcal/mol to pass from 180 to 140°, as calculated at the DFT level. The computed Ca-O and Mg-O bond distances for [M{O(PO3)2}]2- are 2.378 and 2.079Å, when the metal ions link two oxygen atoms from each PO3 group. The computed Ca-O bond lengths for [Ca{CH3OPO2)O(PO3)}]− are 2.482 (PαO2) and 2.358Å (PβO2), showing a significant lengthening for Ca-OPα, when compared to the pyrophosphate derivative. The Ca-O bond lengths for [Ca{O(PO3)3}]3- and [Ca{CH3OPO2)O(PO3)2}]2- are 2.251Å and 2.525 (PαO2), 2.407 and 2.338 (PβO2), and 2.251 and 2.228Å (PγO2), showing a shortening for the Ca-OPγ bond upon methylation. The (Pβ)O-Pγ bond length increases significantly (0.09 Å) upon Ca(II) coordination to (CH3OPO2)O(PO3)2 4- via all the three PO3 groups. This latter result suggests that metal complexes of linear organic-triphosphates have a larger tendency to release the PγO3 group when compared to the free ligand molecules. The electronic contribution to the energy of the complex formation reaction for [Ca{CH2 (PO3)2}]2- is only slightly higher (some 1.8 kcal) than that for [Ca{O(PO3)2}]2-; but is much higher (some 63 kcal) than that relevant to the formation of [Ca{CH3OPO2)O(PO3)2}]2-. Therefore the linear methyltriphosphates (and reasonably nucleoside triphosphates) are predicted to form metal complexes which are less stable than diphosphonate or inorganic diphosphate ligands, at least in the case the organic moiety does not have any appreciable coordination ability toward the metal. The energy of complex formation for [Ca{O(PO3)3}]3- is much higher than that for [Ca{O(PO3)2}]2- and [Ca(PO3)3}]− (some 116 and 345 kcal, respectively). This is in part a rationale for the high dissolving ability (DA) toward CPPD crystals, shown by solutions of pentasodium tripolyphosphate. DA values of 65.4±3.0 μg Ca/mL were detected, via atomic absorption spectroscopy, in solutions of Na5{O(PO3)3} 0.06 M after digestion (1.00 h, 37°C, pH 7.4) in the presence of CPPD crystals. Efficient non-toxic dissolving agents for CPPD crystals are needed to cure chondrocal-cinosis desease. The semi-empirical computations gave correct overall optimized structures and conformations for, at least, the free not-substituted ligands and the relevant Mg(II)-com- plexes. The optimized structure for [Mg{O(PO3)2}]2- has computed P-O(t) and P-O(d) bond distances of 1.503 and 1.598Å, in perfect agreement with the results from DFT calculations.

A novel approach for constant rate delivery of highly soluble bioactives from a simple monolithic system

A novel monolithic drug delivery system for highly water-soluble bioactive agents to follow pH-independent zero-order kinetics is described. The system utilizes a hydrophilic gel-based swellable polymeric material (polyethylene oxide), a model drug (metoprolol tartrate, 100% water soluble at 25°C) and different electrolytes, such as sodium carbonate and/or pentasodium tripolyphosphate. Based on the induction of in situ intra-gel chemical reactions between different ionic species, drug and polymer, a heterogeneous structure manifested as ‘peripheral boundary stiffening,’ is accomplished. The consequence of these interactions essentially include the development of gradient-controlled matrix swelling as elucidated through textural profiling, which may contribute to inhibition of drug solubility and its outward diffusion. Analysis of textural profiles and photomicroscopy distinctly provides information on the disposition of peripheral boundary densification for the electrolyte-containing matrices. Electrolytic conductivity measurements performed with the simultaneous analysis of matrix swelling showed that sodium carbonate forms a highly reactive matrix within the first 3 h of medium penetration. On the other hand, larger molecules such as pentasodium tripolyphosphate maintain a constant conductivity level, which may be related to its lower solubility and diffusion in comparison to sodium carbonate. Based on model fitting and statistical analysis, it is shown that drug release kinetics were adequately described by Mt/M∞=k0t, with zero-order release rate constant k0 of 0.054 h−1. This novel approach in formulation development could potentially be used for constant rate delivery of highly soluble bioactive agents over an extended period for specific biopharmaceutical needs.

Electrolyte-induced compositional heterogeneity: A novel approach for rate-controlled oral drug delivery

In this work a new approach for in situ interactions between drug and electrolyte(s) is devised to control the release of highly water soluble drugs from oral hydrophilic monolithic systems. The model drug diltiazem hydrochloride (water solubility in excess of 50% at 25 °C), in conjunction with specific electrolytes, was principally employed in the design of swellable tablet formulations comprised of hydrophilic polymers such as hydroxypropylmethlcellulose (HPMC) or poly(ethylene oxide) (PEO). Electrolytes such as sodium bicarbonate or pentasodium tripolyphosphate were used to modulate intragel pH dynamics, swelling kinetics, and gel properties. Through in situ ionic interactions (an intragel matrix system composed of different chemical species that promote competition for water of hydration), a compo-sitionally heterogeneous structure referred to as a ‘metamorphic scaffold’ was established. It is shown that this latter structure results in the inhibition of drug dissolution, induction of a differential swelling rate, and attainment of ‘matrix stiffening’ and axially provides a uniform gel layer. Presence of such phases in matrix structure and its influence on swelling dynamics enabled control of diltiazem hydrochloride release in a zero-order manner in different pH environments over a 24-h period. From kinetic analysis using the power law expressions [Mt/M∞ = k1tn, Mt/M∞ = k1tn ± k2t2n] and Hopfenberg model [Mt/M∞ = 1 − (1 − k1t)n], it became apparent that the dynamics of matrix relaxation and controlled erosion were major factors involved in the release mechanism, while the composite rate constant k1 (in Hopfenberg model) decreased by approximately 2-fold in the presence of electrolyte(s). These findings indicated that the dynamics of swelling and gel formation in the presence of ionizable species within hydrophilic matrices provide an attractive alternative for zero-order drug delivery from a simple monolithic system.

Rapid laser fluorometric method for the determination of uranium in soil, ultrabasic rock, plant ash, coal fly ash and red mud samples

A simple and rapid laser fluorometric determination of trace and ultra trace level of uranium in a wide variety of low uranium content materials like soil, basic and ultra basic rocks, plant ash, coal fly ash and red mud samples is described. Interference studies of some common major, minor and trace elements likely to be present in different, geological materials on uranium fluorescence are studied using different fluorescence enhancing reagents like sodium pyrophosphate, orthophosphoric acid, penta sodium tri-polyphosphate and sodium hexametaphosphate. The accurate determination of very low uranium content samples which are rich in iron, manganese and calcium, is possible only after the selective separation of uranium. Conditions suitable for the quantitative single step extraction of 25 ng to 20 μg uranium with tri-n-octylphosphine oxide and single step quantitative stripping with dilute neutral sodium pyrophosphate, which also acts as fluorescence enhancing reagent is studied. The aqueous strip is used for the direct laser fluorometric measurement without any further pretreatment. The procedure is applied for the determination of uranium in soil, basalt, plant ash, coal fly ash and red mud samples. The accuracy of the proposed method is checked by analyzing certain standard reference materials as well as synthetic sample with known quantity of uranium. The accuracy and reproducibility of the method are fairly good with RSD ranging from 3 to 5% depend upon the concentration of uranium.

Chitosan-Polyelectrolyte complexation for the preparation of gel beads and controlled release of anticancer drug. I. Effect of phosphorous polyelectrolyte complex and enzymatic hydrolysis of polymer

Enzymic hydrolyzed chitosan was employed to prepare chitosan–tripolyphosphate and chitosan–polyphosphoric acid gel beads using a polyelectrolyte complexation method for the sustained-release of anticancer agent, 6-mercaptopurine (6-MP). pH responsive swelling ability, drug-release characteristics, and morphology of the chitosan gel bead depends on polyelectrolyte complexation mechanism and molecular weight of the enzymic hydrolyzed chitosan. The complexation mechanism of chitosan beads gelled in pentasodium tripolyphosphate or polyphosphoric acid solution was ionotropic crosslinking or interpolymer complex, respectively. The drug-release patterns of all chitosan gel beads in pH 6.8 seemed to be diffusional based, which might be in accordance with the Higuchi model, whereas release profiles of the chitosan–tripolyphosphate gel beads in pH 1.2 medium seemed to be non-Fickian diffusion controlled due to the swelling or matrix erosion of the beads. The rate of 6-MP releasing from chitosan–tripolyphosphate or chitosan–polyphosphoric acid gel matrix were significantly increased with the decreased molecular weight of enzymic hydrolyzed chitosan. However, the dissolution rates of 6-MP entraped in chitosan–tripolyphosphate and chitosan–polyphosphoric acid gel matrix were significantly slower than the dissolution rate of the original drug. These results indicate that the chitosan–polyphosphoric acid gel bead is a better polymer carrier for the sustained release of anticancer drugs in simulated intestinal and gastric juice medium than the chitosan–tripolyphosphate gel beads. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1868–1879, 1999

Effect of magnesium stearate on chitosan microspheres prepared by an emulsification-coacervation technique

Chitosan microspheres were prepared using an emulsification-coacervation tcchnique. The w/o emulsion comprised a mixture of light and heavy liquid paraffins containing sodium dioctyl sulphosuccinate as the oil phase and chitosan solution as the aqueous phase. Pentasodium tripolyphosphate was included as a counterion. The chitosan microspheres obtained showed a high degree of aggregation. This was markedly reduced, by the incorporation of magnesium stearate in the disperse phase. The resultant microspheres were then discrete, spherical with smooth surfaces. Additionally, with an increasing magnesium stearate content, larger-sized microspheres were produced. The DSC analysis data suggested that the magnesium stearate was converted to stearic acid during the preparation process. Chitosan microspheres containing propranolol hydrochloride were similarly prepared, but their surface was convoluted and their shape not well defined. Unlike the microspheres without drug, thc size of the drug-loaded microspheres decreased with increasing magnesium stearate content. The release of propranolol hydrochloride from the microspheres was fast, irrespective of the content of magnesium stearate. Drug encapsulation efficiency was enhanced when a greater amount of magnesium stearate was used.

Effects of phosphates on shell growth and calcium carbonate crystal formation

Measurements were carried out on the effects of four inorganic phosphates on the rate of CaCO 3 crystallization in vitro and on shell growth of the marine bivalve Rangia cuneata and the freshwater gastropod Helisoma duryi. The rate of in vitro crystallization was determined in inorganic artificial extrapallial fluids by measuring proton release as CaCO 3 forms from Ca 2+ and HCO 3 −. Concentrations of phosphates having a significant inhibitory effect on the rate of in vitro CaCO 3 crystallization were as follows: sodium orthophosphate, 1.25 × 10 −6 M (0.15 ppm); sodium hexametaphosphate, 3.6 × 10 −8 M (0.015 ppm); tetrasodium pyrophosphate, 5.6 × 10 −7 M (0.15 ppm); pentasodium tripolyphosphate, 4.1 × 10 −7 M (0.15 ppm); and ATP 1.0 × 10 −6 M. Sodium hexametaphosphate, tetrasodium pyrophosphate, and pentasodium tripolyphosphate were found to inhibit markedly the incorporation of 45Ca into the growing edge of Rangia during 24 h exposure. However, the concentrations required to produce a significant decrease in 45Ca deposition were four to six orders of magnitude greater than the concentration required to produce an effect on in vitro crystallization. Sodium orthophosphate was without effect on 45Ca deposition in Rangia at concentrations as high as 1500 ppm. Shell growth and mortality of Helisoma exposed to these four phosphates were followed during a 1-mth period. Pentasodium tripolyphosphate and tetrasodium pyrophosphate were the most inhibitory, causing a decreased growth rate and an increase in mortality at concentrations as low as 15 ppm. Fertilized eggs developed and hatched in all four phosphate compounds at 15 ppm and 150 ppm but did not develop in 1500 ppm of any compound.

Environmental impact of detergent builders in California waters

DETERGENT BUILDERS TH~ MOST widely-used detergent builders in the United States today are condensed phosphates--either penta sodium tripolyphosphate or tetrasodium pyrophosphate. Currently on the market also are synthetic detergent products built with various complex alkaline si!icates, with metasilicates, and with sodium carbonate. A promising builder, nitrilotriacetic acid (NTA) has been marketed to a limited degree in the recent past but has been removed from the market in the United States. Compounds under investigation that hold promise as builders include citrates and other low molecular weight polycarboxylic acids and high molecular weight polyelectrolytes. It may be reasonably assumed that current regulatory attitudes and past experience by detergent manufacturers will dictate that neither toxic nor nonbiodegradable materials will be introduced into a detergent product. Because of this, the attention of this study was initially focused on the effects of minerals such as nitrogen, phosphorus, silica, inorganic carbon, and degradable organic carbon. By the reasoning that follows it was possible to further focus the study objectives to two minerals--nitrogen and phosphorus (and principally the latter) as having the most significant current or future significant effects on water quality.

The spectrophotometric determination of vanadium in ilmenite

A new procedure has been developed for eliminating interference from titanium in the N-benzoyl-N-phenylhydroxylamine procedure for determination of vanadium. After the oxidation of vanadium (IV) with potassium permanganate, vanadium(V)-BPHA complex is extracted into chloroform from sulphuric acid and converted to the chloride form before removal of the original aqueous phase. Coextracted titanium is removed from the isolated organic phase by extracting with a solution of pentasodium tripolyphosphate in 2 M sulphuric acid. Appropriate arrangement of the order of reagent addition avoids reduction of vanadium(V) in the strongly acidic chloride systems.