Comprehensive characterization of ERV-K (HML-8) in the chimpanzee genome revealed less genomic activity than humans.

Endogenous retroviruses (ERVs) originate from ancestral germline infections caused by exogenous retroviruses. Throughout evolution, they have become fixed within the genome of the animals into which they were integrated. As ERV elements coevolve with the host, they are normally epigenetically silenced and can become upregulated in a series of physiological and pathological processes. Generally, a detailed ERV profile in the host genome is critical for understanding the evolutionary history and functional performance of the host genome. We previously characterized and cataloged all the ERV-K subtype HML-8 loci in the human genome; however, this has not been done for the chimpanzee, the nearest living relative of humans. In this study, we aimed to catalog and characterize the integration of HML-8 in the chimpanzee genome and compare it with the integration of HML-8 in the human genome. We analyzed the integration of HML-8 and found that HML-8 pervasively invaded the chimpanzee genome. A total of 76 proviral elements were characterized on 23/24 chromosomes, including detailed elements distribution, structure, phylogeny, integration time, and their potential to regulate adjacent genes. The incomplete structure of HML-8 proviral LTRs will undoubtedly affect their activity. Moreover, the results indicated that HML-8 integration occurred before the divergence between humans and chimpanzees. Furthermore, chimpanzees include more HML-8 proviral elements (76 vs. 40) and fewer solo long terminal repeats (LTR) (0 vs. 5) than humans. These results suggested that chimpanzee genome activity is less than the human genome and that humans may have a better ability to shape and screen integrated proviral elements. Our work is informative in both an evolutionary and a functional context for ERVs.

Identification of differentially expressed HERV-K(HML-2) loci in colorectal cancer.

Colorectal cancer is one of the malignant tumors with the highest mortality rate in the world. Survival rates vary significantly among patients at various stages of the disease. A biomarker capable of early diagnosis is required to facilitate the early detection and treatment of colorectal cancer. Human endogenous retroviruses (HERVs) are abnormally expressed in various diseases, including cancer, and have been involved in cancer development. Real-time quantitative PCR was used to detect the transcript levels of HERV-K(HML-2) gag, pol, and env in colorectal cancer to systematically investigate the connection between HERV-K(HML-2) and colorectal cancer. The results showed that HERV-K(HML-2) transcript expression was significantly higher than healthy controls and was consistent at the population and cell levels. We also used next-generation sequencing to identify and characterize HERV-K(HML-2) loci that were differentially expressed between colorectal cancer patients and healthy individuals. The analysis revealed that these loci were concentrated in immune response signaling pathways, implying that HERV-K impacts the tumor-associated immune response. Our results indicated that HERV-K might serve as a screening tumor marker and a target for tumor immunotherapy in colorectal cancer.

Preparation of MoFs-Derived Cobalt Oxide/Carbon Nanotubes Composites for High-Performance Asymmetric Supercapacitor.

Metal-organic frameworks (MOFs)-derived metallic oxide compounds exhibit a tunable structure and intriguing activity and have received intensive investigation in recent years. Herein, this work reports metal-organic frameworks (MOFs)-derived cobalt oxide/carbon nanotubes (MWCNTx@Co3O4) composites by calcining the MWCNTx@ZIF-67 precursor in one step. The morphology and structure of the composite were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM) characterization. The compositions and valence states of the compounds were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Benefiting from the structurally stable MOFs-derived porous cobalt oxide frameworks and the homogeneous conductive carbon nanotubes, the synthesized MWCNTx@Co3O4 composites display a maximum specific capacitance of 206.89 F·g-1 at 1.0 A·g-1. In addition, the specific capacitance of the MWCNT3@Co3O4//activated carbon (AC) asymmetric capacitor reaches 50 F·g-1, and has an excellent electrochemical performance. These results suggest that the MWCNTx@Co3O4 composites can be a potential candidate for electrochemical energy storage devices.

Cocrystallization of 5-fluorouracil with gallic acid: A novel 5-fluorouracil cocrystal displaying synergistic anti-tumor activity both in oral and intraperitoneal injection administration.

Gallic acid (GA) is a naturally occurring polyphenolic compound exhibiting anti-tumor activity. To clarify the capability of GA in optimizing the in vitro/in vivo properties of the first line anti-tumor drug 5-fluorouracil (5-FU) and achieve synergistically enhanced anti-tumor activity, a novel cocrystal hydrate of 5-FU-GA-H2O was successfully screened and characterized based on various spectroscopic and experimental analysis including Fourier transform infrared spectroscopy (FT-IR), Raman spectra (Raman), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric (TG) and scanning electric microscope (SEM) techniques. The results suggested the existence of hydrogen bonding interactions between C=O group of 5-FU and O-H group of GA. Although the dissolution rate and solubility of 5-FU-GA-H2O cocrystal were slowed and lowered compared with that of 5-FU, respectively, the membrane permeability was enhanced for cocrystal compared with that of intact 5-FU and physical mixture (PM) of 5-FU and GA. For the cocrystal, the cumulative amount per unit area of permeated 5-FU in the first 10 h was 2.56 and 9.97 times of that of pure 5-FU and PM, respectively, in the case that transmembrane behavior of 5-FU depended on the type of solution from which the powder was dissolved. Meanwhile, improvement on oral bioavailability by co-crystallization was observed; AUC0-t of cocrystal was 2.78-fold higher than that of 5-FU. Furthermore, the cocrystal displayed a superior cytotoxic activity on 4T1 mouse breast cancer cells compared with pure 5-FU and even the PM. It was confirmed that the cocrystal solution induced higher autophagic flux than those of 5-FU and PM in 4T1 cell, suggesting that autophagy rather than apoptosis mainly mediated cell death. The obvious difference of tumor inhibition activity between PM and cocrystal in intraperitoneal injection administration indicated that some of the interactions formed in the solid cocrystal could retain in solution in some way. Benefiting from synergistic cytotoxicity, drug efficacy in vivo was enhanced through injection administration of solution from which cocrystal was dissolved.

Co-amorphous formulation of dipyridamole with p-hydroxybenzoic acid: Underlying molecular mechanisms, physical stability, dissolution behavior and pharmacokinetic study.

Coamorphization has been proven to be an effective approach to improve bioavailability of poorly soluble active pharmaceutical ingredients (APIs) by virtue of solubilization, and also contributes to overcome limitation of physical stability associated with amorphous drug alone. In current work, a co-amorphous formulation of dipyridamole (DPM), a poor solubility drug, with p-hydroxybenzoic acid (HBA) was prepared and investigated. At a molar ratio of 1:2, DPM and HBA were melted result in the formation of a binary co-amorphous system. The DPM-HBA co-amorphous was structurally characterized by powder X-ray diffraction (PXRD), temperature modulated differential scanning calorimetry (mDSC), high performance liquid chromatography (HPLC) and solution state 1H nuclear magnetic resonance (1H NMR). The molecular mechanisms in the co-amorphous were further analysed via Fourier-transform infrared (FTIR) and Raman spectroscopies, as well as density functional theory (DFT) calculation. All the results consistently revealed the presence of hydrogen bonding interactions between -OH of DPM and -COOH on HBA. Accelerated test and glass transition kinetics showed excellent physical stability of DPM-HBA co-amorphous compared with amorphous DPM along with glass transition temperatures (Tg). The phase-solubility study indicated that complexation occurred between DPM and HBA in solution, which contributed to the solubility and dissolution enhancement of DPM in co-amorphous system. Pharmacokinetic study of co-amorphous DPM-HBA in mouse plasma revealed that the DPM exhibited 1.78-fold and 2.64-fold improvement in AUC0­∞ value compared with crystalline and amorphous DPM, respectively. This current study revealed coamorphization is an effective approach for DPM to improve the solubility and biopharmaceutical performance.

Comprehensive identification and characterization of the HERV-K (HML-9) group in the human genome.

BACKGROUND: Human endogenous retroviruses (HERVs) result from ancestral infections caused by exogenous retroviruses that became incorporated into the germline DNA and evolutionarily fixed in the human genome. HERVs can be transmitted vertically in a Mendelian fashion and be stably maintained in the human genome, of which they are estimated to comprise approximately 8%. HERV-K (HML1-10) transcription has been confirmed to be associated with a variety of diseases, such as breast cancer, lung cancer, prostate cancer, melanoma, rheumatoid arthritis, and amyotrophic lateral sclerosis. However, the poor characterization of HML-9 prevents a detailed understanding of the regulation of the expression of this family in humans and its impact on the host genome. In light of this, a precise and updated HERV-K HML-9 genomic map is urgently needed to better evaluate the role of these elements in human health. RESULTS: We report a comprehensive analysis of the presence and distribution of HERV-K HML-9 elements within the human genome, with a detailed characterization of the structural and phylogenetic properties of the group. A total of 23 proviruses and 47 solo LTR elements were characterized, with a detailed description of the provirus structure, integration time, potential regulated genes, transcription factor binding sites (TFBS), and primer binding site (PBS) features. The integration time results showed that the HML-9 elements found in the human genome integrated into the primate lineage between 17.5 and 48.5 million years ago (mya). CONCLUSION: The results provide a clear characterization of HML-9 and a comprehensive background for subsequent functional studies.

High Expression of HERV-K (HML-2) Might Stimulate Interferon in COVID-19 Patients.

Background. Interferon is a marker of host antiviral immunity, which is disordered in COVID-19 patients. ERV can affect the secretion of interferon through the cGAS-STING pathway. In this study, we explored whether IFN-I and HERV-K (HML-2) were activated in COVID-19 patients and whether there was an interaction between them. Methods. We collected blood samples from COVID-19 patients and healthy controls. We first detected the expression of HERV-K (HML-2) gag, env, and pol genes and IFN-I-related genes between patients and healthy people by qPCR, synchronously detected VERO cells infected with SARS-CoV-2. Then, the chromosome distributions of highly expressed HERV-K (HML-2) gag, env, and pol genes were mapped by the next-generation sequencing results, and GO analysis was performed on the related genes. Results. We found that the HERV-K (HML-2) gag, env, and pol genes were highly expressed in COVID-19 patients and VERO cells infected with SARS-CoV-2. The interferon-related genes IFNB1, ISG15, and IFIT1 were also activated in COVID-19 patients, and GO analysis showed that HERV-K (HML-2) can regulate the secretion of interferon. Conclusions. The high expression of HERV-K (HML-2) might activate the increase of interferon in COVID-19 patients, proving that HERV-K does not only play a negative role in the human body.

Significant Upregulation of HERV-K (HML-2) Transcription Levels in Human Lung Cancer and Cancer Cells.

Lung cancer is the second most common cancer worldwide and the leading cause of cancer death in the world. Therefore, there is an urgent need to develop new and effective biomarkers for diagnosis and treatment. Under this circumstance, human endogenous retroviruses (HERVs) were recently introduced as novel biomarkers for cancer diagnosis. This study focused on the correlation between lung cancer and HERV-K (HML-2) transcription levels. At the cellular level, different types of lung cancer cells and human normal lung epithelial cells were used to analyze the transcription levels of the HERV-K (HML-2) gag, pol, and env genes by RT-qPCR. At the level of lung cancer patients, blood samples with background information from 734 lung cancer patients and 96 healthy persons were collected to analyze the transcription levels of HERV-K (HML-2) gag, pol, and env genes. The results showed that the transcriptional levels of the HERV-K (HML-2) gag, pol, and env genes in lung cancer cells and lung cancer patient blood samples were significantly higher than those in the healthy controls, which was also verified by RNAScope ISH technology. In addition, we also found that there was a correlation between the abnormal transcription levels of HERV-K (HML-2) genes in lung cancer patients and the clinicopathological parameters of lung cancer. We also identified the distribution locations of the gag, pol, and env primer sequences on each chromosome and analyzed the function of these loci. In conclusion, HERV-K (HML-2) genes may be a potential biomarker for the diagnosis of lung cancer.

Spectroscopic Methodology and Molecular Docking Studies on Changes in Binding Interaction of Felodipine with Bovine Serum Albumin Induced by Cocrystallization with ß-Resorcylic Acid.

In the present study, a novel cocrystal of felodipine (FEL) and ß-resorcylic acid (ßRA) was developed. We specially focused on the change of binding pattern with bovine serum albumin (BSA) induced by cocrystallization of FEL with ßRA. The solid characterizations and density functional theory (DFT) simulation verified that FEL-ßRA cocrystal formed in equimolar ratio (1 : 1 M ratio) through C=O…H-O hydrogen bond between C=O group in FEL and O-H group in ßRA. The binding interactions between FEL-ßRA system and BSA were studied using fluorescence spectral and molecular docking methods. Two guest molecule systems, including a physical mixture of FEL and ßRA and FEL-ßRA cocrystal were performed binding to BSA in molecular docking. According to the Kb and binding energy, the supramolecular form of FEL-ßRA system was retained during binding to BSA. Molecular docking simulation suggested that FEL and its cocrystal inserted into the subdomain IIIA (site II') of BSA. The interactions between FEL and BSA including hydrogen bonding with ASN390 residue and intermolecular hydrophobic interactions with LEU429 and LEU452 residues. However, the size of supramolecular FEL-ßRA better matched that of active cavity of BSA; the cocrystal is closely bound to BSA through hydrogen bonding with ASN390 residue and intermolecular hydrophobic interactions with LEU429, VAL432, LEU452 and ILE387 residues. This change on binding affinity of FEL to BSA induced by cocrystallization with ßRA provided theoretical basis to evaluate the transportation, distribution and metabolism of cocrystal drug.

The mechanism of binding with the α-glucosidase in vitro and the evaluation on hypoglycemic effect in vivo: Cocrystals involving synergism of gallic acid and conformer.

Cocrystallization of Active Pharmaceutical Ingredients (API) with formers can induce positive or negative synergistic effects on activity; however, the underlying mechanism is unclear. In this study, we screened two cocrystals of gallic acid (GA): GA-p-aminobenzoic acid (cocrystal A) and GA-amino acetic acid (cocrystal B). Solubility, dissolution rate, and oral bioavailability and hypoglycemic effect of the two cocrystals were evaluated. Additionally, we examined the effect induced by cocrystallization of GA with each former on inhibition activity on α-glucosidase, a protein target involved in hypoglycemic effects. Cocrystals A and B were constructed in a 1:1 API/former molar ratio by CO⋯HN and OH⋯OC hydrogen bonds, respectively. As predicted, cocrystallization improved oral bioavailability; AUC0-∞s of cocrystal A and B were 2.24-fold and 1.70-fold higher than that of GA. Interestingly, the α-glucosidase inhibition rate increased with cocrystal A (i.e., positive synergism) and decreased with cocrystal B (i.e., negative synergism) compared to GA alone. For each cocrystal system, an obvious difference in the α-glucosidase inhibition rate between cocrystal and its physical mixture (PM) of API and former was observed. The 1H NMR analysis of two cocrystals and their respective PM indicated that hydrogen bond interactions between API and former molecules were just present in the solutions of cocrystal; but not in that of PMs. Molecular docking indicated that the hydrogen bonds between GA and CCF achieved binding with α-glucosidase in the form of supramolecular. Due to improvements in both oral bioavailability and α-glucosidase inhibition rate, the maximum hypoglycemic rate in diabetic mice treated with cocrystal A was 3.4-fold higher than that of GA alone. Conversely, although cocrystal B displayed improved bioavailability compared with GA alone, the maximum hypoglycemic rate remained almost unchanged due to the negative synergism on α-glucosidase inhibition activity of GA and amino acetic acid. Cocrystallization with each former induced variation not only on physiochemical properties and bioavailability but also on biological profiles involving inhibition rate on target proteins, which likely contributed to the observed positive and negative synergistic effects on API activity.

Characterizations and Assays of α-Glucosidase Inhibition Activity on Gallic Acid Cocrystals: Can the Cocrystals be Defined as a New Chemical Entity During Binding with the α-Glucosidase?

Cocrystallization with co-former (CCF) has proved to be a powerful approach to improve the solubility and even bioavailability of poorly water-soluble active pharmaceutical ingredients (APIs). However, it is still uncertain whether a cocrystal would exert the pharmacological activity in the form of a new chemical entity, an API-CCF supramolecule. In the present study, gallic acid (GA)-glutaric acid and GA-succinimide cocrystals were screened. The solubility, dissolution rate and oral bioavailability of the two cocrystals were evaluated. As expected, AUCs of GA-glutaric acid and GA-succinimide cocrystals were 1.86-fold and 2.60-fold higher than that of single GA, respectively. Moreover, experimental evaluations on α-glucosidase inhibition activity in vitro and theoretical simulations were used to detect whether the two cocrystals would be recognized as a new chemical entity during binding with α-glucosidase, a target protein in hypoglycemic mechanisms. The enzyme activity evaluation results showed that both GA and glutaric acid displayed α-glucosidase inhibition activity, and GA-glutaric acid cocrystals showed strengthened α-glucosidase inhibition activity at a moderate concentration, which is attributed to synergism of the two components. Molecular docking displayed that the GA-glutaric acid complex deeply entered the active cavity of the α-glucosidase in the form of a supramolecule, which made the guest-enzyme binding configuration more stable. For the GA and succinimide system, succinimide showed no enzyme inhibition activity, however, the GA-succinimide complex presented slightly higher α-glucosidase inhibition activity than that of GA. Molecular docking simulation indicated that the guest molecules entering the active cavity of the α-glucosidase were free GA and succinimide, not the GA-succinimide supramolecule.

RETRACTED: Cocrystals of curcumin-isonicotinamide and curcumin-gallic acid: Does the weak forces in cocrystals effect on binding profiles with BSA and cell cytotoxicity?

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Authors. There were errors in the handling of the data of the BSA binding experiments, which affected the conclusion on the binding affinity of the different cocrystals to BSA. After rigorous discussion, the authors think further investigation should be performed in this project to get the precise results.

Experimental and DFT simulation study of a novel felodipine cocrystal: Characterization, dissolving properties and thermal decomposition kinetics.

In this study, a new cocrystal of felodipine (Fel) and glutaric acid (Glu) with a high dissolution rate was developed using the solvent ultrasonic method. The prepared cocrystal was characterized using X-ray powder diffraction, differential scanning calorimetry, thermogravimetric (TG) analysis, and infrared (IR) spectroscopy. To provide basic information about the optimization of pharmaceutical preparations of Fel-based cocrystals, this work investigated the thermal decomposition kinetics of the Fel-Glu cocrystal through non-isothermal thermogravimetry. Density functional theory (DFT) simulations were also performed on the Fel monomer and the trimolecular cocrystal compound for exploring the mechanisms underlying hydrogen bonding formation and thermal decomposition. Combined results of IR spectroscopy and DFT simulation verified that the Fel-Glu cocrystal formed via the NH⋯OC and CO⋯HO hydrogen bonds between Fel and Glu at the ratio of 1:2. The TG/derivative TG curves indicated that the thermal decomposition of the Fel-Glu cocrystal underwent a two-step process. The apparent activation energy (Ea) and pre-exponential factor (A) of the thermal decomposition for the first stage were 84.90 kJ mol-1 and 7.03 × 107 min-1, respectively. The mechanism underlying thermal decomposition possibly involved nucleation and growth, with the integral mechanism function G(α) of α3/2. DFT calculation revealed that the hydrogen bonding between Fel and Glu weakened the terminal methoxyl, methyl, and ethyl groups in the Fel molecule. As a result, these groups were lost along with the Glu molecule in the first thermal decomposition. In conclusion, the formed cocrystal exhibited different thermal decomposition kinetics and showed different Ea, A, and shelf life from the intact active pharmaceutical ingredient.

Comparison of the physical and thermodynamic stability of amorphous azelnidipine and its coamorphous phase with piperazine.

A major challenge in drug development is that the majority of drugs are water insoluble, and a powerful method to conquer this obstacle is to transfer a crystalline drug into its amorphous phase (AP) or coamorphous phase (CAP) with a coformer. In the present study, the physical and chemical stabilities of an AP and a CAP based on the dihydropyridine calcium ion antagonist azelnidipine (AZE) were investigated using thermal analysis and a solution chemistry method. The identification of two APs (named α-AP and ß-AP, from crystalline α-AZE and ß-AZE, respectively) and one AZE-piperazine CAP was attempted using powder X-ray diffraction, temperature modulated differential scanning calorimetry and Fourier-transform infrared spectroscopy. The transition thermodynamics from the two APs and the CAP to stable crystalline ß-AZE (ß-Cry) were investigated using a solubility method. The solubility of the two APs, the CAP and ß-Cry in 0.01 M HCl medium at 298, 304, 310, 316 and 322 K was investigated; the values obtained were used to calculate the thermodynamic parameters of the transition reaction. The transition temperatures of α-AP, ß-AP and the CAP to form ß-Cry in 0.01 M HCl were 237.7, 400.3, and 231.4 K, respectively. The glass transition temperature (T g) values of α-AP, ß-AP and the CAP were 365.5, 358.9 and 347.6 K, respectively, indicating a high physical stability for α-AP. However, ß-AP proved to be the most thermodynamically stable form at room temperature compared with α-AP and CAP in the 0.01 M HCl medium. As evidenced by those observations, no general relationship occurred between the solid physical stability and the solution chemical stability for AP and CAP. The kinetics of the solid-state decomposition, studied using DSC analysis, showed that the activation energies for decomposition of α-AP, ß-AP and CAP at high temperatures were 133.0, 114.2 and 131.6 kJ mol-1, respectively.

Solid state characterization of azelnidipine-oxalic acid co-crystal and co-amorphous complexes: The effect of different azelnidipine polymorphs.

In present study, based on the two polymorphs (α and ß form) of azelnidipine (AZE), 12 complexes of AZE and oxalic acid (OXA) were prepared by solvent-assisted grinding (SG) and neat powder grinding (NG) methods at the AZE/OXA molar ratios of 2:1, 1:1, and 1:2. The effect of the different polymorphs of AZE on the micro-structure of the complexes were investigated by powder X-ray diffraction (PXRD), tempreture modulated differential scanning calorimetry and thermogravimetric analysis, cryo-field emission scanning electron microscope system, fourier transform infrared (FTIR), and solid-state nuclear magnetic resonance spectroscopy. ß-AZE-OXA co-crystal was produced at ß-AZE/OXA molar ratio of 2:1 when SG method was used; while α-AZE was used to produce α-AZE-OXA co-crystal at same condition. However, the other 10 combinations were in co-amorphous forms, including the NG samples with α (or ß)-AZE/OXA molar ratios of 2:1, 1:1 (SG and NG), and 1:2 (SG and NG). Although the XRD pattern and IR spectra of the two co-crystals showed no difference, the melting enthalpy and specific heat cp of the ß-AZE-OXA co-crystal was higher than that of the α-AZE-OXA co-crystal, indicating that the numbers of solvent molecules which entered the two co-crystal lattices were different. Interestingly, obvious difference occurred in the IR spectra between the α-AZE-OXA and ß-AZE-OXA co-amorphous systems. 1745cm-1 wave-numbers, which were assigned to the free CO groups, appeared in the α-AZE-OXA co-amorphous systems even when just a small amount of OXA was introduced, thereby indicating the presence of different intermolecular forces in the two series of co-amorphous forms. The solubility in different media and the dissolution rate in 0.1molL-1 HCl of the 12 complexes were determined. The dramatically improved dissolution rates of the α- and ß-AZE-OXA 1:2 (NG) combinations in vitro showed potential in improving the physicochemical properties of AZE by co-amorphous complex formation.

Metal ion-assisted drug-loading model for novel delivery system of cisplatin solid lipid nanoparticles with improving loading efficiency and sustained release.

Metal ion-assisted drug loading model, in which metal ion was used to modify the microstructure of lipid layer, has been developed to improve drug loading efficiency of solid lipid nanoparticles (SLNs). The microstructure and properties of metal ion-assisted cisplatin-loading SLNs were investigated by infra-red spectroscopy, fluorescence spectroscopy and zetasizer. The reactions of hydrogenated soybean lecithin with Zn(2+), Cu(2+), Mn(2+ )and Mg(2+ )have been detected; the mechanism for higher drug encapsulation efficiency (EE) has been investigated. In metal ion introduction SLNs, the compact degree of the lipid molecules was increased due to the electrostatic interaction between metal ions and phospholipid acyl and choline polarity groups, which result in increasing of drug EE. Meanwhile, these electrostatic interactions slowed the releasing rate of encapsulated drug. The study of cytotoxic activity in vitro indicated that the cell cytotoxicity of metal ions introduction SLNs depended on both cell uptake of SLNs and drug releasing from SLNs.

Decolorization of methyl orange by green rusts with hydrogen peroxide at neutral pH.

Heterogeneous Fenton-like processes using green rusts (GRs) with hydrogen peroxide (H2O2) were studied to decolorize methyl orange (MO) in aqueous solution at an initial pH of 7.0. In this study, two types of crystal structure for GRs, the hydroxycarbonate GR(CO3(2-)) (GR1) and the hydroxysulphate GR(SO4(2-)) (GR2), were synthesized by partial oxidation of Fe(OH)2 suspension under light irradiation and distinguished by X-ray diffraction (XRD) due to different characteristic peaks. In oxidation reactions, decolorization rate of MO, bubbling air through the solution, was about 65% (experiment B), whereas, it was up to 95% in the presence of H2O2 (experiment C) within 60 min. The comparative tests of GR1 and GR2 show that the reduction capability of GR2 is stronger than GR1, which may be due to Fe(II) content and interlayer anions. XRD analysis and Fourier transform infrared spectroscopy revealed that the oxidation end products of GR2 were mainly a poorly crystallized mixture of magnetite (Fe3O4) and hydroxy ferric oxide (FeOOH). However, when GR was immediately oxidized, the weakly crystallized goethite (α-FeOOH) and lepidocrocite (γ-FeOOH) were formed for O2 and H2O2, respectively. Based on the intermediates obtained, a probable decolorization mechanism has been proposed.

Preparation, characterization, and evaluation of dipfluzine-benzoic acid co-crystals with improved physicochemical properties.

PURPOSE: To prepare and characterize the co-crystal of dipfluzine and benzoic acid. To investigate the feasibility of the co-crystal for improving solubility and a faster dissolution rate in vitro and evaluate the bioavailability and tissue distribution of co-crystal in vivo. METHODS: A novel dipfluzine-benzoic acid co-crystal prepared using the solvent-assisted co-grinding and the solvent ultrasonic methods were identified and characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), as well as Raman, solid-state nuclear magnetic resonance (ssNMR), and terahertz (THz) spectroscopy. Pharmacokinetics and tissue distribution were tested in vivo using murine models. Statistics analysis for dissolution data of co-crystal in vitro and animal experiment data in vivo were evaluated using t-test. RESULTS: Results of PXRD and DSC identified the dipfluzine-benzoic acid co-crystals were formed with a molar ratio of 1:2. The IR, Raman, and ssNMR spectra verified the formation of O-H · · · O and O-H · · · F hydrogen bonds. The complex constant, K, was evaluated to be 10(9) orders of magnitude with Δ r G < 0. The co-crystal solubility, the rate of drug dissolution and the relative bioavailability were approximately 500 times, five times and double that of dipfluzine, respectively. Increased solubility of co-crystal did not reduce distribution in the brain; the mean concentrations in the brain increased, but the differences had no statistic significance (p > 0.05). CONCLUSIONS: The co-crystal of dipfluzine-benzoic acid improved the physicochemical properties of dipfluzine, such as solubility and dissolution rate. Furthermore, the increased relative bioavailability of co-crystal indicated the potential use in further clinical study.

Solid state characterizations and analysis of stability in azelnidipine polymorphs.

Azelnidipine, a new dihydropyridine calcium ion antagonist, was protected by patent in Japan. In present study, identifications of the crystal phases, including two polymorphic and a pseudopolymorphic crystal forms of azelnidipine, were attempted using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), IR-, Raman-, THz-, and ss-NMR-spectroscopy. PXRD identified three different crystal forms, while, spectroscopy analysis provided the information of crystal structure involving intermolecular interactions. The transition thermodynamics of the azelnidipine polymorphs were extensively investigated by solubility method. The solubility of the two polymorphs of α and ß in 50% ethanol at 25, 31, 37, 42, and 49°C was investigated; the values obtained were used to calculate the thermodynamic parameters of the transition reaction. The temperature of polymorphic phase transition in 50% ethanol was 50.78°C, and the values of ΔG(α,ß)(θ), ΔH(α,ß)(θ), and ΔS(α,ß)(θ) at 25°C were -1.18 kJ·mol(-1), -14.81 kJ·mol(-1), and -45.73 J·mol(-1)·K(-1), respectively. Form ß was proved to be thermodynamic stable form at room temperature and enantiotropically related with form α. The kinetics of the solid-state decomposition, studied using DSC analysis, showed that the activation energies of decomposition of the polymorphs α and ß at high temperatures were 148.67 and 151.93 kJ·mol(-1).