| 1. |
- Briggner, Lars-Erik, et al.
(författare)
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In Silico Solid State Perturbation for Solubility Improvement
- 2014
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Ingår i: ChemMedChem. - : Wiley. - 1860-7179 .- 1860-7187. ; 9:4, s. 724-726
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Tidskriftsartikel (refereegranskat)abstract
- Solubility is a frequently recurring issue within pharmaceutical industry, and new methods to proactively resolve this are of fundamental importance. Here, a novel methodology is reported for intrinsic solubility improvement, using insilico prediction of crystal structures, by perturbing key interactions in the crystalline solid state. The methodology was evaluated with a set of benzodiazepine molecules, using the two-dimensional molecular structure as the only a priori input. The overall trend in intrinsic solubility was correctly predicted for the entire set of benzodiazepines molecules. The results also indicate that, in drug compound series where the melting point is relatively high (i.e., brick dust compounds), the reported methodology should be very suitable for identifying strategically important molecular substitutions to improve solubility. As such, this approach could be a useful predictive tool for rational compound design in the early stages of drug development.
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| 2. |
- Briggner, Lars-Erik, et al.
(författare)
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Solid-State Perturbation for Solubility Improvement : A Proof of Concept
- 2011
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Ingår i: ChemMedChem. - : Wiley. - 1860-7179. ; 6:1, s. 60-62
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Tidskriftsartikel (refereegranskat)abstract
- Simple and rational: The intrinsic solubility of a compound can be systematically improved by perturbing key interactions in its crystal structure. By carefully choosing the perturbation, the end result will be a molecule similar to the original one, but with significantly higher solubility. This methodology is demonstrated on a subset of benzodiazepines, resulting in significant improvement of their solubility.
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| 3. |
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| 4. |
- Olsson, Lars-Fride, et al.
(författare)
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In vitro formation of nanocrystalline carbonate apatite - A structural and morphological analogue of atherosclerotic plaques
- 2007
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :26, s. 4123-4127
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Tidskriftsartikel (refereegranskat)abstract
- The in vitro formation of carbonate apatite in solutions with ion concentrations comparable to those in human serum was studied. The composition and morphology of the resulting apatite precipitate displayed a hierarchical assembly of elongated plate-shaped nanocrystals of carbonate apatite analogous to previously characterized bioapatites formed in The main conclusion is that so-called bioapatites may form in vitro and that precipitation inhibitors most likely are essential for the prevention of spontaneous calcification at normal human serum ion concentrations.
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| 5. |
- Sandin, Karin, et al.
(författare)
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A theoretical investigation of the supersaturation of basic calcium phosphate in serum of dialysis patients
- 2006
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Ingår i: Journal of Applied Biomaterials and Biomechanics. - 1722-6899. ; 4:2, s. 80-86
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Forskningsöversikt (refereegranskat)abstract
- Extraosseous calcification in hemodialysis (HD) patients consists mainly of biological apatite, idealized as hydroxyapatite. Other suggested calcium phosphates are octacalcium phosphate (OCP) and brushite, both known to be hydroxyapatite precursors. Whatever the mechanisms of mineral deposition are, these mechanisms are always required to produce a supersaturated state, and that state can be calculated from the solubility product (SP) of the relevant mineral. Supersaturation in relation to serum ionized calcium [Ca2+] and total inorganic serum phosphate (Pi) under normal and hyperphosphatemic conditions has been calculated. While supersaturation with respect to hydroxyapatite and OCP always exists, and supersaturation with respect to Ca5(PO4)3(HCO3)·4H2O is just above the limit, supersaturation with respect to brushite solely occurs under hyperphosphatemic conditions. In order to avoid supersaturation with respect to brushite the maximum serum phosphate level allowed is 1.9 mmol/L (5.8 mg/dl) and the calcium-phosphate product (Ca x— P) 4.5 (mmol/L)2 (56 (mg/dl))2.
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| 6. |
- Sandin, Karin, et al.
(författare)
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Formation of carbonated apatite particles from a supersaturated inorganic blood serum model
- 2009
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 20:8, s. 1677-1687
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Tidskriftsartikel (refereegranskat)abstract
- Pathological calcification is common among for instance dialysis patients, and this causes an increase in mortality risk. An elevated serum phosphate concentration among those patients strongly correlates to this increase. In this work investigations of the conditions, composition, crystallinity and morphology of in vitro calcification are performed and related to results from in vivo studies. The study was performed under conditions mimicking physiological ones, i.e. a pH around 7.40, a temperature of 37A degrees C, an ionic strength of 150 mM and ion concentrations close to those in human serum including the effects of elevated phosphate concentrations. The course of precipitation involves an initial precipitate that subsequently re-dissolves to give another precipitate, in accordance with the well-known Ostwald ripening theory. The final bulk precipitate consists of a macroscopically amorphous carbonated apatite. The amorphous apatite is formed from assemblies of spherical particles in the mu m range, in turn composed of nano-crystalline needles of about 10 x 100 nm. Even the initially formed precipitate, as well as a small amount of precipitate that occurs on the liquid surface, consist of a carbonated calcium phosphate. The in vitro observed carbonated apatite bears strong resemblance to in vivo cardiovascular calcification known from literature.
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| 7. |
- Sandin, Karin, et al.
(författare)
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The observation of nano-crystalline calcium phosphate precipitate in a simple supersaturated inorganic blood serum model - composition and morphology
- 2009
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Ingår i: Journal of Applied Biomaterials and Biomechanics. - 1722-6899 .- 1724-6024. ; 7:1, s. 13-22
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Tidskriftsartikel (refereegranskat)abstract
- Aim. Calcium phosphate deposition in blood vessels is correlated to increased mortality risk. In this study, the formation of solid calcium phosphate in an in vitro solution mimicking the inorganic part of blood serum was studied. Methods. The precipitates formed were analyzed using several experimental techniques, including infrared spectroscopy, Raman spectroscopy, X-ray energy dispersive spectroscopy, chemical analysis of combustion gases, thermogravimetric analysis, as well as transmission electron microscopy and scanning electron microscopy. Results. The results indicate a microscopically amorphous but nano-crystalline material with an overall apatite structure. A plausible stoichiometry was determined to Ca-5(PO4)(3)(HCO3)center dot 4H(2)O with an estimated solubility constant of 6.10(-39) (mol/L)(9). Bicarbonate in the water solution was shown to be essential for the precipitation, giving implications for in vitro studies. Conclusions. The calcium phosphate formed in this study shows many similarities to pathological calcium phosphates regarding composition, morphology and crystallinity.
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| 8. |
- Abdelhamid, Hani Nasser, et al.
(författare)
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Towards implementing hierarchical porous zeolitic imidazolate frameworks in dye-sensitized solar cells
- 2019
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Ingår i: Royal Society Open Science. - : Royal Society Publishing. - 2054-5703. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- A one-pot method for encapsulation of dye, which can be applied for dye-sensitized solar cells (DSSCs), and synthesis of hierarchical porous zeolitic imidazolate frameworks (ZIF-8), is reported. The size of the encapsulated dye tunes the mesoporosity and surface area of ZIF-8. The mesopore size, Langmuir surface area and pore volume are 15 nm, 960-1500 m(2). g(-1) and 0.36-0.61 cm(3). g(-1), respectively. After encapsulation into ZIF-8, the dyes show longer emission lifetimes (greater than 4-8-fold) as compared to the corresponding non-encapsulated dyes, due to suppression of aggregation, and torsional motions.
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| 9. |
- Baranov, A. I., et al.
(författare)
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2D metal slabs in new nickel-tin chalcogenides Ni(7-delta)SnQ(2) (Q=Se, Te) : average crystal and electronic structures, chemical bonding and physical properties
- 2004
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 177:10, s. 3616-3625
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Tidskriftsartikel (refereegranskat)abstract
- A systematic search for mixed low-valence, nickel-tin chalcogenides performed by establishing phase relations in the parts of Ni-Sn-Se and Ni-Sn-Te ternary systems resulted in the discovery of two new compounds, Ni5.62SnSe2 and Ni5.78SnTe2 Single crystals of both compounds were prepared by chemical transport with iodine and crystal structures were determined by single crystal X-ray investigation. The ED patterns for Ni5.78SnTe2 showed the presence of satellite reflections, which indicate a modulated structure with qapproximate to0.4a*. Average crystal structures of both compounds were determined to be of tetragonal symmetry (Sp.gr.I4/mmm, Z = 2) with a = 3.6890(8) Angstrom, c = 18.648(3) Angstrom, R-w = 0.0716 and a = 3.7680(5) Angstrom, c = 19.419(4) Angstrom, R-w, 0.0832, correspondingly, and are isostructural to known Ni5.72SbSe2 and Ni5.66SbTe2. Measurements were carried out for both compounds with respect to thermal, electrical and magnetic properties. Ab initio band structure calculations were also performed to take a first glance into the electronic structure of such type compounds. The anisotropy of their band structure was found. Physical property measurements showed both compounds to be the anisotropic metallic conductors and paramagnetics. Calculated difference charge density maps revealed pairwise covalent and multicenter metallic nature of the d-metal-chalcogen and d-metal-p-metal interactions, respectively.
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| 10. |
- Baranov, A. I., et al.
(författare)
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New metal-rich sulfides Ni6SnS2 and Ni9Sn2S2 with a 2D metal framework : Synthesis, crystal structure, and bonding
- 2003
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 42:21, s. 6667-6672
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Tidskriftsartikel (refereegranskat)abstract
- Two new, metal-rich nickel-tin sulfides Ni6SnS2 and Ni9Sn2S2 were found by establishing phase relations in the ternary Ni-Sn-S system at 540 degreesC. Their single crystals were prepared by means of chemical vapor transport reactions. Single crystal X-ray diffraction was used for the determination of their crystal structures. Both compounds crystallize in a tetragonal system (/4/mmm, No. 139, Z = 2, a = 3.646(1) Angstrom, c = 18.151(8) Angstrom for Ni6SnS2, and a = 3.678(1) Angstrom, c = 25.527(8) Angstrom for Ni9Sn2S2). Their crystal structures represent a new structure type and can be considered as assembled from bimetallic nickel-tin and nickel-sulfide slabs alternating along the crystallographic c axis. DFT band structure calculations showed the bonding within the bimetallic slabs to have a delocalized, multicenter nature, typical for metallic systems, and predominantly classical, pairwise bonding between nickel and sulfur.
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