DL-Tartaric acid

Structure determination of a new cocrystal of carbamazepine and DL-tartaric acid by synchrotron powder X-ray diffraction.[Pubmed:32132279]

Acta Crystallogr C Struct Chem. 2020 Mar 1;76(Pt 3):225-230.

The crystal structure of a new cocrystal of carbamazepine (systematic name: 5H-dibenzo[b,f]azepine-5-carboxamide, C15H12N2O) and DL-Tartaric acid (C4H6O6), obtained by liquid-assisted grinding, was solved by powder X-ray diffraction (PXRD). The high-resolution PXRD pattern of this new phase was recorded at room temperature thanks to synchrotron experiments at the European Synchrotron Radiation Facility (Grenoble, France). The starting structural model was generated by a Monte-Carlo simulated annealing method. The final structure was obtained through Rietveld refinement and an energy minimization simulation was used to estimate the H-atom positions. The stability of the proposed structure as a function of temperature was also assessed from molecular dynamics simulations. The symmetry is monoclinic (space group P21/c) and contains eight molecules per unit cell, namely, four DL-Tartaric acid and four carbamazepine molecules.

Effect of solvent polarity in mechanochemistry: preparation of a conglomerate vs. racemate.[Pubmed:31436771]

Chem Commun (Camb). 2019 Sep 10;55(73):10900-10903.

Cocrystallization of racemic DL-Tartaric acid (dl-ta) and achiral isoniazid (ISN) was investigated using mechanochemistry. Neat grinding (NG) and liquid-assisted grinding (LAG) in the presence of non-polar liquids result in the formation of a conglomerate (ISN.d-ta/ISN.l-ta); whereas LAG with polar liquids yields racemic salt ISN.dl-ta. The effect of solvent polarity and dipole moment in mechanochemistry is discussed.

Designing of Stable Co-crystals of Zoledronic Acid Using Suitable Coformers.[Pubmed:31366831]

Chem Pharm Bull (Tokyo). 2019;67(8):816-823.

In this present study a new co-crystals of zoledronic acid with DL-Tartaric acid and nicotinamide has been developed with improved solubility. Zoledronic acid is a class III drug with poor oral bioavailability due to its poor permeability and low aqueous solubility; hence an attempt has been made to improve its solubility by co-crystallization technology. Pharmaceutical cocrystals are multi-component crystals with a stoichiometric ratio of active pharmaceutical ingredients (APIs) and cocrystal coformers (CCFs) that are assembled by noncovalent interactions such as hydrogen bonds, pi-pi packing, and Vander Waals forces. In this study the coformers selected were DL-Tartaric acid and nicotinamide based on ease of hydrogen bond formation. The co-crystal of zoledronic acid with DL-Tartaric acid were prepared in three ratios (1 : 1, 1 : 2 and 2 : 1) by slow solvent evaporation method and with nicotinamide in 1 : 1 ratio by dry grinding method. The formation of co-crystal was confirmed by powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC) and Fourier transform (FT)IR. The dynamic solubility of co-crystals with DL-Tartaric acid in the ratios 1 : 1, 1 : 2 and 2 : 1 increased by fold as compared to pure drug.

Effect of chemical additives on electrokinetic remediation of Cr-contaminated soil coupled with a permeable reactive barrier.[Pubmed:31218039]

R Soc Open Sci. 2019 May 1;6(5):182138.

Chromium (Cr) contamination in soil, especially Cr(VI), is a serious threat to the environment and human health. The electrokinetic remediation (EKR) is a promising technology to remediate the Cr(VI). Therefore, in this study, EKR coupled with a permeable reactive barrier (PRB) was used to treat the Cr(VI)-contaminated soil. The CTMAB-Z, a modified zeolite (prepared with cetyltrimethyl ammonium bromide) alone and a mixture of CTMAB-Z and Fe(0) were used as PRB-1 and PRB-2 reactive media, respectively. The effect of chemical enhancers/additives, i.e. DL-Tartaric acid and Tween 80 on EKR of Cr(VI) was also analysed in the contrasting experiments. While the effects of repair time, voltage gradient and DL-Tartaric acid concentration on Cr(VI) remediation were investigated by using the multifactor orthogonal experiment which was based on contrasting experiments. The contrasting experiment results showed that the highest Cr(VI) removal rate (66.27%) and leaching efficiency (71.29%) were observed in the experimental group which had DL-Tartaric acid and PRB-2. Furthermore, the multifactor orthogonal experiment results had depicted that the highest Cr(VI) removal rate (80.92%) and leaching efficiency (85.25%) were achieved after treating the samples at a voltage gradient of 2.5 V cm(-1) for 8 days in the presence of 0.15 M concentration of DL-Tartaric acid. This study demonstrated that Cr(VI) remediation through EKR process could be significantly enhanced by the use of PRB and additives.

Concomitant cocrystal and salt: no interconversion in the solid state.[Pubmed:30833526]

Acta Crystallogr C Struct Chem. 2019 Mar 1;75(Pt 3):313-319.

A cocrystal and a molecular salt of beta-alanine and DL-Tartaric acid, C3H8NO2(+).C4H4O6(-), of the same chemical composition, were studied over a wide temperature range by single-crystal and powder X-ray diffraction. Neither the interconversion between the two phases nor any polymorphic transitions were observed in the temperature range from 100 K to the melting points. This contrasts with the solvent-mediated phase transition from the salt to the cocrystal in a slurry that has been documented earlier.

Experimental and theoretical investigations of tartaric acid isomers by terahertz spectroscopy and density functional theory.[Pubmed:30029194]

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Dec 5;205:312-319.

The terahertz (THz) absorption spectra of l-, d-, and DL-Tartaric acid have been measured in the frequency range from 0.2 to 2.0THz by terahertz time-domain spectroscopy (THz-TDS). The characteristic absorption peaks of these three tartaric acid isomers were obtained, which showed remarkable difference between enantiomers (l- and d-tartaric acid) and the racemic compound (DL-Tartaric acid) in their peak frequencies. In parallel with the experimental study, theoretical calculations on isolated-molecule and unit cell of tartaric acids using density functional theory (DFT) were also performed for simulating the experimental THz spectrum features, which were in good agreement with the experimental data. Results demonstrate that THz-TDS can distinguish the tiny diversity between tartaric acid chiral isomers and its racemic compound, and provided an effective method for molecular identification in biological and biomedical engineering.

The effect of amino acid backbone length on molecular packing: crystalline tartrates of glycine, beta-alanine, gamma-aminobutyric acid (GABA) and DL-alpha-aminobutyric acid (AABA).[Pubmed:29400333]

Acta Crystallogr C Struct Chem. 2018 Feb 1;74(Pt 2):177-185.

We report a novel 1:1 cocrystal of beta-alanine with DL-Tartaric acid, C3H7NO2.C4H6O6, (II), and three new molecular salts of DL-Tartaric acid with beta-alanine {3-azaniumylpropanoic acid-3-azaniumylpropanoate DL-Tartaric acid-DL-tartrate, [H(C3H7NO2)2](+).[H(C4H5O6)2](-), (III)}, gamma-aminobutyric acid [3-carboxypropanaminium DL-tartrate, C4H10NO2(+).C4H5O6(-), (IV)] and DL-alpha-aminobutyric acid {DL-2-azaniumylbutanoic acid-DL-2-azaniumylbutanoate DL-Tartaric acid-DL-tartrate, [H(C4H9NO2)2](+).[H(C4H5O6)2](-), (V)}. The crystal structures of binary crystals of DL-Tartaric acid with glycine, (I), beta-alanine, (II) and (III), GABA, (IV), and DL-AABA, (V), have similar molecular packing and crystallographic motifs. The shortest amino acid (i.e. glycine) forms a cocrystal, (I), with DL-Tartaric acid, whereas the larger amino acids form molecular salts, viz. (IV) and (V). beta-Alanine is the only amino acid capable of forming both a cocrystal [i.e. (II)] and a molecular salt [i.e. (III)] with DL-Tartaric acid. The cocrystals of glycine and beta-alanine with DL-Tartaric acid, i.e. (I) and (II), respectively, contain chains of amino acid zwitterions, similar to the structure of pure glycine. In the structures of the molecular salts of amino acids, the amino acid cations form isolated dimers [of beta-alanine in (III), GABA in (IV) and DL-AABA in (V)], which are linked by strong O-H...O hydrogen bonds. Moreover, the three crystal structures comprise different types of dimeric cations, i.e. (A...A)(+) in (III) and (V), and A(+)...A(+) in (IV). Molecular salts (IV) and (V) are the first examples of molecular salts of GABA and DL-AABA that contain dimers of amino acid cations. The geometry of each investigated amino acid (except DL-AABA) correlates with the melting point of its mixed crystal.

Supramolecular hydrogen-bonding patterns in two cocrystals of the N(7)-H tautomeric form of N(6)-benzoyladenine: N(6)-benzoyladenine-3-hydroxypyridinium-2-carboxylate (1/1) and N(6)-benzoyladenine-DL-tartaric acid (1/1).[Pubmed:26524172]

Acta Crystallogr C Struct Chem. 2015 Nov;71(Pt 11):985-90.

Two novel cocrystals of the N(7)-H tautomeric form of N(6)-benzoyladenine (BA), namely N(6)-benzoyladenine-3-hydroxypyridinium-2-carboxylate (3HPA) (1/1), C12H9N5O.C6H5NO3, (I), and N(6)-benzoyladenine-DL-Tartaric acid (TA) (1/1), C12H9N5O.C4H6O6, (II), are reported. In both cocrystals, the N(6)-benzoyladenine molecule exists as the N(7)-H tautomer, and this tautomeric form is stabilized by intramolecular N-H...O hydrogen bonding between the benzoyl C=O group and the N(7)-H hydrogen on the Hoogsteen site of the purine ring, forming an S(7) motif. The dihedral angle between the adenine and phenyl planes is 0.94 (8) degrees in (I) and 9.77 (8) degrees in (II). In (I), the Watson-Crick face of BA (N6-H and N1; purine numbering) interacts with the carboxylate and phenol groups of 3HPA through N-H...O and O-H...N hydrogen bonds, generating a ring-motif heterosynthon [graph set R2(2)(6)]. However, in (II), the Hoogsteen face of BA (benzoyl O atom and N7; purine numbering) interacts with TA (hydroxy and carbonyl O atoms) through N-H...O and O-H...O hydrogen bonds, generating a different heterosynthon [graph set R2(2)(4)]. Both crystal structures are further stabilized by pi-pi stacking interactions.

Chiral SiO2 and Ag@SiO2 Materials Templated by Complexes Consisting of Comblike Polyethyleneimine and Tartaric Acid.[Pubmed:26350940]

Chemistry. 2015 Oct 26;21(44):15667-75.

A facile avenue to fabricate micrometer-sized chiral (L-, D-) and meso-like (dl-) SiO2 materials with unique structures by using crystalline complexes (cPEI/tart), composed of comblike polyethyleneimine (cPEI) and L-, D-, or DL-Tartaric acid, respectively, as catalytic templates is reported. Interestingly, both chiral crystalline complexes appeared as regularly left- and right-twisted bundle structures about 10 mum in length and about 5 mum in diameter, whereas the dl-form occurred as circular structures with about 10 mum diameter. Subsequently, SiO2 @cPEI/tart hybrids with high silica content (>55.0 wt %) were prepared by stirring a mixture containing tetramethoxysilane (TMOS) and the aggregates of the crystalline complexes in water. The chiral SiO2 hybrids and calcined chiral SiO2 showed very strong CD signals and a nanofiber-based morphology on their surface, whereas dl-SiO2 showed no CD activity and a nanosheet-packed disklike shape. Furthermore, metallic silver nanoparticles (Ag NPs) were encapsulated in each silica hybrid to obtain chiral (D and L forms) and meso-like (dl form) Ag@SiO2 composites. Also, the reaction between L-cysteine (Lcys) and these Ag@SiO2 composites was preliminarily investigated. Only chiral L- and D-Ag@SiO2 composites promoted the reaction between Lcys and Ag NPs to produce a molecular [Ag-Lcys]n complex with remarkable exciton chirality, whereas the reaction hardly occurred in the case of meso-like (dl-) Ag@SiO2 composite.

Cocrystals of acyclovir with promising physicochemical properties.[Pubmed:25407552]

J Pharm Sci. 2015 Jan;104(1):98-105.

Cocrystal forming ability of antiviral drug acyclovir (ACV) with different coformers was studied. Three cocrystals containing ACV with fumaric acid, malonic acid, and DL-Tartaric acid were isolated. Methods of cocrystallization included grinding with dropwise solvent addition and solvent evaporation. The cocrystals were characterized by powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The crystal structure of the cocrystal with fumaric acid as conformer was determined by single crystal X-ray diffraction. Formation of supramolecular synthon was observed in the cocrystal. Stability with respect to relative humidity for the three cocrystals was evaluated. The aqueous solubility of the ACV-cocrystal materials was significantly improved with a maximum of malonic acid cocrystal, which was about six times more soluble at 35 degrees C compared with that of parent ACV. The dissolution profile indicates that at any particular dissolution time, the concentration of cocrystals in the solution was higher than that of the parent ACV, and malonic acid cocrystals had a maximum release of about twice than the hydrated ACV.

Phosphorylated silica nanotubes: preparation and characterization.[Pubmed:23851944]

Nanotechnology. 2013 Aug 9;24(31):315701.

Recently, the strategy of doping inorganic particles into polymer membranes to modify them has been studied intensively. However, these inorganic particles have a disadvantage without being in good compatibility with the polymers. To enhance the compatibility between inorganic particles and polymers, phosphorylated silica nanotubes (PSNTs) with specific high ratios of length to diameter are prepared. Silica nanotubes (SNTs) are prepared through the hydrolysis of tetraethyl orthosilicate in a mixture of aqueous ammonia and DL-Tartaric acid, then PSNTs are obtained by silylation and phosphorylation modifications. The optimum synthesis conditions of PSNTs are explored; in addition, the as-prepared PSNTs are characterized by Fourier transform infrared, transmission electron microscope, BET, x-ray photoelectron spectroscopy analysis and thermogravimetric analysis. The results indicate that the ratio of length to diameter of the PSNTs is approximately 20, the thickness of the tube wall is 20 nm, the specific surface area of the PSNTs is 460.2 m(2) g(-1), the inner diameter of the PSNTs is 76 nm, many mesopores are distributed in the tube walls of the PSNTs, and the PSNTs have numerous hydroxyl active sites along their length direction. Therefore, PSNTs are desirable as suitable fillers of polymer membranes.

Determination of alpha-hydroxy acids and their enantiomers in fruit juices by ligand exchange CE with a dual central metal ion system.[Pubmed:23423790]

Electrophoresis. 2013 May;34(9-10):1327-33.

The content of alpha-hydroxy acids and their enantiomers can be used to distinguish authentic and adulterated fruit juices. Here, we investigated the use of ligand exchange CE with two kinds of central metal ion in a BGE for the simultaneous determination of enantiomers of dl-malic, dl-tartaric and dl-isocitric acids, and citric acid. Ligand exchange CE with 100 mM d-quinic acid as a chiral selector ligand and 10 mM Cu(II) ion as a central metal ion could enantioseparate DL-Tartaric acid but not dl-malic acid or dl-isocitric acid. Addition of 1.8 mM Sc(III) ion to the BGE with 10 mM Cu(II) ion to create a dual central metal ion system permitted the simultaneous determination of these alpha-hydroxy acid enantiomers and citric acid. The proposed ligand exchange CE was thus well suited for detecting adulteration of fruit juices.

Enantioseparation of alpha-hydroxy acids by chiral ligand exchange CE with a dual central metal ion system.[Pubmed:22930546]

Electrophoresis. 2012 Sep;33(18):2920-4.

Using two kinds of central metal ions in a background electrolyte, ligand exchange CE was investigated for the simultaneous enantioseparation of dl-malic, dl-tartaric, and dl-isocitric acids. Ligand exchange CE with 100 mM d-quinic acid as a chiral selector ligand and 10 mM Cu(II) ion as a central metal ion could enantioseparate DL-Tartaric acid but not dl-malic acid or dl-isocitric acid. A dual central metal ion system containing 0.5 mM Al(III) ion in addition to 10 mM Cu(II) ion in the background electrolyte enabled the simultaneous enantioseparation of the three alpha-hydroxy acids. These results suggest that the use of a dual central metal ion system can be useful for enantioseparation by ligand exchange CE.

Hydrochloride salt co-crystals: preparation, characterization and physicochemical studies.[Pubmed:22686294]

Pharm Dev Technol. 2013 Mar-Apr;18(2):443-53.

Co-crystallization approach for modification of physicochemical properties of hydrochloride salt is presented. The objective of this investigation was to study the effect of co-crystallization with different co-crystal formers on physicochemical properties of fluoxetine hydrochloride (FH). FH was screened for co-crystallization with a series of carboxylic acid co-formers by slow evaporation method. Photomicrographs and melting points of crystalline phases were determined. The co-crystals were characterized by FTIR, DSC and PXRD methods. Solubility of co-crystals was determined in water and buffer solutions. Powder and intrinsic dissolution profiles were assessed for co-crystals. Physical mixtures of drug and co-formers were used for comparisons at characterizations and physicochemical properties evaluation stages. Four co-crystals of FH viz. Fluoxetine hydrochloride-maleic acid (FH-MA), Fluoxetine hydrochloride-glutaric acid (FH-GA), Fluoxetine hydrochloride-L-tartaric acid (FH-LTA) and Fluoxetine hydrochloride-DL-Tartaric acid (FH-DLTA) were obtained from screening experiments. Physical characterization showed that they have unique crystal morphology, thermal, spectroscopic and X-ray diffraction properties. Solubility and dissolution studies showed that Fluoxetine hydrochloride-maleic acid co-crystal possess high aqueous solubility in distilled water, pH 4.6, 7.0 buffer solutions and dissolution rate in distilled water than that of pure drug. Co-crystal formation approach can be used for ionic API to tailor its physical properties.