scholarly journals Piroxicam Loading onto Mesoporous Silicas by Supercritical CO2 Impregnation

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2500
Author(s):  
Marta Gallo ◽  
Luca Serpella ◽  
Federica Leone ◽  
Luigi Manna ◽  
Mauro Banchero ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Water Solubility ◽  
Solid Dispersions ◽  
Mesoporous Silicas ◽  
Incipient Wetness Impregnation ◽  
Pore Blocking ◽  
Physico Chemical ◽  
Adsorption From Solution ◽  
First Time ◽  
Loading Procedure

Piroxicam (PRX) is a commonly prescribed nonsteroidal anti-inflammatory drug. Its efficacy, however, is partially limited by its low water solubility. In recent years, different studies have tackled this problem and have suggested delivering PRX through solid dispersions. All these strategies, however, involve the use of potentially harmful solvents for the loading procedure. Since piroxicam is soluble in supercritical CO2 (scCO2), the present study aims, for the first time, to adsorb PRX onto mesoporous silica using scCO2, which is known to be a safer and greener technique compared to the organic solvent-based ones. For comparison, PRX is also loaded by adsorption from solution and incipient wetness impregnation using ethanol as solvent. Two different commercial mesoporous silicas are used (SBA-15 and Grace Syloid® XDP), which differ in porosity order and surface silanol population. Physico-chemical analyses show that the most promising results are obtained through scCO2, which yields the amorphization of PRX, whereas some crystallization occurs in the case of adsorption from solution and IWI. The highest loading of PRX by scCO2 is obtained in SBA-15 (15 wt.%), where molecule distribution appears homogeneous, with very limited pore blocking.

Complexation with Hydroxypropyl-gama-Cyclodextrin of Birch Tree Extract Physico-chemical Characterisation of their Binary Products

2008 ◽  
Vol 59 (6) ◽  
Author(s):  
Codruta Soica ◽  
Cristina A. Dehelean ◽  
Valentin Ordodi ◽  
Diana Antal ◽  
Vicentiu Vlaia
Keyword(s):  
Inclusion Complexes ◽  
Water Solubility ◽  
In Vitro Dissolution ◽  
Molar Ratio ◽  
Bark Extract ◽  
Birch Bark ◽  
Preparation Methods ◽  
Birch Tree ◽  
Physico Chemical

Birch bark contains important pentacyclic triterpens that determine an anticancer, anti-inflammatory and antiviral activity. The compounds can be extracted by simple procedures with organic solvents. The major problem of this type of triterpens is their low water solubility which can be increased by physical procedures like cyclodextrin complexation. The aim of present study was to analyse the products between birch bark extract and hydroxypropyl-g -cyclodextrin. Hydroxypropyl-g -cyclodextrin (HPGCD) was used as a host to improve its solubility in water, via inclusion complex formation. In order to obtain the inclusion complexes, 1:2 molar ratio and two preparation methods (physical mixing, kneading) were used. The inclusion complexes were analyzed by in vitro dissolution tests, thermal analysis and X-ray diffraction.

Amorphous and Crystalline Particulates: Challenges and Perspectives in Drug Delivery

2017 ◽  
Vol 23 (3) ◽  
pp. 350-361 ◽  
Author(s):  
Hisham Al-Obaidi ◽  
Mridul Majumder ◽  
Fiza Bari
Keyword(s):  
Crystal Engineering ◽  
Drug Carrier ◽  
Solid Dispersions ◽  
Chemical Properties ◽  
Pharmaceutical Product ◽  
Water Soluble ◽  
Amorphous Form ◽  
Physico Chemical ◽  
Water Soluble Drugs ◽  
Amorphous Drug

Crystalline and amorphous dispersions have been the focus of academic and industrial research due to their potential role in formulating poorly water-soluble drugs. This review looks at the progress made starting with crystalline carriers in the form of eutectics moving towards more complex crystalline mixtures. It also covers using glassy polymers to maintain the drug as amorphous exhibiting higher energy and entropy. However, the amorphous form tends to recrystallize on storage, which limits the benefits of this approach. Specific interactions between the drug and the polymer may retard this spontaneous conversion of the amorphous drug. Some studies have shown that it is possible to maintain the drug in the amorphous form for extended periods of time. For the drug and the polymer to form a stable mixture they have to be miscible on a molecular basis. Another form of solid dispersions is pharmaceutical co-crystals, for which research has focused on understanding the chemistry, crystal engineering and physico-chemical properties. USFDA has issued a guidance in April 2013 suggesting that the co-crystals as a pharmaceutical product may be a reality; but just not yet! While some of the research is still oriented towards application of these carriers, understanding the mechanism by which drug-carrier miscibility occurs is also covered. Within this context is the use of thermodynamic models such as Flory-Huggins model with some examples of studies used to predict miscibility.

Physico-Chemical Characteristics of Sapota (Chikoo) Powder based Value Added Pasta Product using Semolina (Suji) and Maida

2020 ◽  
Vol 7 (04) ◽  
Author(s):  
SATYA NARAYAN SINGH ◽  
RAJESH G BURBADE ◽  
HITESH SANCHAVAT ◽  
P S PANDIT
Keyword(s):  
Bulk Density ◽  
Crude Protein ◽  
Water Solubility ◽  
Value Added ◽  
Absorption Capacity ◽  
Oil Absorption ◽  
Minimum Value ◽  
Maximum Value ◽  
Physico Chemical ◽  
Specific Length

The cereals of today are more nutritious and healthful than ever before. Cereals processing is one of the oldest and the most essential part of all food technologies. Pasta products and noodles have been staple foods since ancient times in many countries all over the world. In this study pasta formulation was substituted with blending sapota powder in different proportions (4 levels i.e. 0%, 10%, 20%, 30%) into semolina and maida flour separately. Pasta products were prepared using eight different formulations and adding water (approximately 31% of total weight) in DOLLY pasta extruder machine. All the samples were evaluated for physical properties: specific length (mm/g), bulk density (kg/m3), specific density (kg/m3) and porosity (%); functional properties: water absorption index (%), water solubility index (%) and oil absorption capacity (ml/g) and nutritional compositions: moisture (%), crude protein (%), fat (%) and carbohydrate (%). Highest specific length 36.20 mm/g was observed for T5 treatment, low bulk density 368.10 kg/m3 was observed for T5 and highest porosity 9.24% was found for T1 treatment. The maximum WAI, WSI values 325.83%, 17.33% respectively was observed for T1 treatment and minimum value of oil absorption capacity 1.06 ml/g for T8 treatment. The moisture content of dried pasta products was found in the range of 6 to 7%. The maximum value of crude protein 13.07% was found for T5 and minimum value 8.81% for T4 treatments. The fat contents were varied from 1.02% to 1.28 %. The maximum value of carbohydrate was 76.20% for T1 and minimum value 65.41% for T8.

scholarly journals Extraction and Mass Spectrometric Characterization of Terpenes Recovered from Olive Leaves Using a New Adsorbent-Assisted Supercritical CO2 Process

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1301
Author(s):  
Zully J. Suárez Montenegro ◽  
Gerardo Álvarez-Rivera ◽  
Jose A. Mendiola ◽  
Elena Ibáñez ◽  
Alejandro Cifuentes
Keyword(s):  
Aluminum Oxide ◽  
Silica Gel ◽  
Supercritical Co2 ◽  
Olive Leaves ◽  
Fractionation Process ◽  
Selective Enrichment ◽  
Adsorption Desorption ◽  
First Time ◽  
By Products

This work reports the use of GC-QTOF-MS to obtain a deep characterization of terpenoid compounds recovered from olive leaves, which is one of the largest by-products generated by the olive oil industry. This work includes an innovative supercritical CO2 fractionation process based on the online coupling of supercritical fluid extraction (SFE) and dynamic adsorption/desorption for the selective enrichment of terpenoids in the different olive leaves extracts. The selectivity of different commercial adsorbents such as silica gel, zeolite, and aluminum oxide was evaluated toward the different terpene families present in olive leaves. Operating at 30 MPa and 60 °C, an adsorbent-assisted fractionation was carried out every 20 min for a total time of 120 min. For the first time, GC-QTOF-MS allowed the identification of 40 terpenoids in olive leaves. The GC-QTOF-MS results indicate that silica gel is a suitable adsorbent to partially retain polyunsaturated C10 and C15 terpenes. In addition, aluminum oxide increases C20 recoveries, whereas crystalline zeolites favor C30 terpenes recoveries. The different healthy properties that have been described for terpenoids makes the current SFE-GC-QTOF-MS process especially interesting and suitable for their revalorization.

scholarly journals Monoclinic and Orthorhombic NaMnO2 for Secondary Batteries: A Comparative Study

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1230
Author(s):  
Jessica Manzi ◽  
Annalisa Paolone ◽  
Oriele Palumbo ◽  
Domenico Corona ◽  
Arianna Massaro ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Reversible Capacity ◽  
Beta Phase ◽  
X Ray Diffraction ◽  
Positive Electrodes ◽  
Detailed Structural Analysis ◽  
Physico Chemical ◽  
Sodium Batteries ◽  
The Impact ◽  
First Time

In this manuscript, we report a detailed physico-chemical comparison between the α- and β-polymorphs of the NaMnO2 compound, a promising material for application in positive electrodes for secondary aprotic sodium batteries. In particular, the structure and vibrational properties, as well as electrochemical performance in sodium batteries, are compared to highlight differences and similarities. We exploit both laboratory techniques (Raman spectroscopy, electrochemical methods) and synchrotron radiation experiments (Fast-Fourier Transform Infrared spectroscopy, and X-ray diffraction). Notably the vibrational spectra of these phases are here reported for the first time in the literature as well as the detailed structural analysis from diffraction data. DFT+U calculations predict both phases to have similar electronic features, with structural parameters consistent with the experimental counterparts. The experimental evidence of antisite defects in the beta-phase between sodium and manganese ions is noticeable. Both polymorphs have been also tested in aprotic batteries by comparing the impact of different liquid electrolytes on the ability to de-intercalated/intercalate sodium ions. Overall, the monoclinic α-NaMnO2 shows larger reversible capacity exceeding 175 mAhg−1 at 10 mAg−1.

SECONDARY CHANGES IN CARBONATE ROCKS OF OIL AND GAS COMPLEXES

2020 ◽  
pp. 18-23
Author(s):  
M.A. Tugarova
Keyword(s):  
Carbonate Rocks ◽  
Oil And Gas ◽  
Carbonate Reservoirs ◽  
Fundamental Importance ◽  
Schematic Diagram ◽  
Reservoir Properties ◽  
Physico Chemical ◽  
Chemical Conditions ◽  
First Time

The article considers the secondary transformations of carbonate rocks of oil and gas complexes, which are of fundamental importance in the formation of reservoir properties. For the first time, a schematic diagram, illustrating the regularities of secondary processes in carbonate reservoirs and their relationship with the physico-chemical conditions of the stratosphere is proposed.

scholarly journals Estimation of the retention behaviour of s-triazine derivatives applying multiple regression analysis of selected molecular descriptors

2013 ◽  
pp. 229-237 ◽  
Author(s):  
Lidija Jevric ◽  
Sanja Podunavac-Kuzmanovic ◽  
Strahinja Kovacevic ◽  
Natasa Kalajdzija ◽  
Bratislav Jovanovic
Keyword(s):  
Dissociation Constant ◽  
Water Solubility ◽  
Molecular Descriptors ◽  
Chemical Properties ◽  
Log P ◽  
Retention Factors ◽  
Solute Retention ◽  
Physico Chemical ◽  
Hydrophilic Lipophilic Balance ◽  
Triazine Derivatives

The estimation of retention factors by correlation equations with physico-chemical properties can be of great helpl in chromatographic studies. The retention factors were experimentally measured by RP-HPTLC on impregnated silica gel with paraffin oil using two-component solvent systems. The relationships between solute retention and modifier concentration were described by Snyder?s linear equation. A quantitative structure-retention relationship was developed for a series of s-triazine compounds by the multiple linear regression (MLR) analysis. The MLR procedure was used to model the relationships between the molecular descriptors and retention of s-triazine derivatives. The physicochemical molecular descriptors were calculated from the optimized structures. The physico-chemical properties were the lipophilicity (log P), connectivity indices (?), total energy (Et), water solubility (log W), dissociation constant (pKa), molar refractivity (MR), and Gibbs energy (GibbsE) of s-triazines. A high agreement between the experimental and predicted retention parameters was obtained when the dissociation constant and the hydrophilic-lipophilic balance were used as the molecular descriptors. The empirical equations may be successfully used for the prediction of the various chromatographic characteristics of substances, with a similar chemical structure.

scholarly journals Amphiphilic Nanocarrier Systems for Curcumin Delivery in Neurodegenerative Disorders

Medicines ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 126 ◽  
Author(s):  
Miora Rakotoarisoa ◽  
Angelina Angelova
Keyword(s):  
Neurodegenerative Disorders ◽  
Liquid Crystalline ◽  
Water Solubility ◽  
Neuronal Loss ◽  
Drug Solubility ◽  
Neuroprotective Effects ◽  
Slowing Down ◽  
Combination Treatments ◽  
Physico Chemical ◽  
Lateral Sclerosis

Neurodegenerative diseases have become a major challenge for public health because of their incurable status. Soft nanotechnology provides potential for slowing down the progression of neurodegenerative disorders by using innovative formulations of neuroprotective antioxidants like curcumin, resveratrol, vitamin E, rosmarinic acid, 7,8-dihydroxyflavone, coenzyme Q10, and fish oil. Curcumin is a natural, liposoluble compound, which is of considerable interest for nanomedicine development in combination therapies. The neuroprotective effects of combination treatments can involve restorative mechanisms against oxidative stress, mitochondrial dysfunction, inflammation, and protein aggregation. Despite the anti-amyloid and anti-tau potential of curcumin and its neurogenesis-stimulating properties, the utilization of this antioxidant as a drug in neuroregenerative therapies has huge limitations due to its poor water solubility, physico-chemical instability, and low oral bioavailability. We highlight the developments of soft lipid- and polymer-based delivery carriers of curcumin, which help improve the drug solubility and stability. We specifically focus on amphiphilic liquid crystalline nanocarriers (cubosome, hexosome, spongosome, and liposome particles) for the encapsulation of curcumin with the purpose of halting the progressive neuronal loss in Alzheimer’s, Parkinson’s, and Huntington’s diseases and amyotrophic lateral sclerosis (ALS).

scholarly journals Cyclam-Based Chelators Bearing Phosphonated Pyridine Pendants for 64Cu-PET Imaging : Synthesis, Physico-Chemical Studies, Radiolabeling and Bioimaging.

2020 ◽  
Author(s):  
Richard Knighton ◽  
Thibault Troadec ◽  
Valerie Mazan ◽  
Patricia La Saëc ◽  
Séverine Marionneau-Lambot ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Copper Complexes ◽  
The Body ◽  
Renal Elimination ◽  
X Ray Diffraction ◽  
Physico Chemical ◽  
Chemical Studies ◽  
First Time ◽  
Excellent Stability

Herein we present the preparation of two novel cyclam-based macrocycles (te1pyp and cb-te1pyp), bearing phosphonate-appended pyridine side-arms for the coordination of copper(II) ions in the context of 64Cu PET imaging. The two ligands have been prepared through conventional protection-alkylation sequences on cyclam, and their coordination properties have been thoroughly investigated. The corresponding copper complexes have been fully characterized in the solid-state (X-Ray diffraction analysis) and in solution (EPR and UV-Vis spectroscopies). Potentiometric studies, combined with spectrometry, have also allowed us to determine their thermodynamic stability constants, confirming their high affinity for copper(II) cations. The kinetic inertness of the complexes has also been verified by acid-assisted dissociation experiments, enabling their use in 64Cu-PET imaging in mice for the first time. Indeed, the two ligands could be quantitatively radiolabeled under mild conditions, and the resulting 64Cu complexes have demonstrated excellent stability in serum. PET imaging demon-strated a set of features emerging from the combination of picolinates and phosphonate units: high stability in vivo, fast clear-ance from the body via renal elimination, and most interestingly, very low fixation in the liver. The latter is in contrast with what was observed for monopicolinate cyclam (te1pa), that had a non-negligible accumulation in the liver, owing probably to its different charge and lipophillicity. These results thus pave the way for the use of such phosphonated pyridine chelators for in vivo 64Cu-PET imaging.

scholarly journals Cyclam-Based Chelators Bearing Phosphonated Pyridine Pendants for 64Cu-PET Imaging : Synthesis, Physico-Chemical Studies, Radiolabeling and Bioimaging.

2020 ◽  
Author(s):  
Richard Knighton ◽  
Thibault Troadec ◽  
Valerie Mazan ◽  
Patricia La Saëc ◽  
Séverine Marionneau-Lambot ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Copper Complexes ◽  
The Body ◽  
Renal Elimination ◽  
X Ray Diffraction ◽  
Physico Chemical ◽  
Chemical Studies ◽  
First Time ◽  
Excellent Stability

Herein we present the preparation of two novel cyclam-based macrocycles (te1pyp and cb-te1pyp), bearing phosphonate-appended pyridine side-arms for the coordination of copper(II) ions in the context of 64Cu PET imaging. The two ligands have been prepared through conventional protection-alkylation sequences on cyclam, and their coordination properties have been thoroughly investigated. The corresponding copper complexes have been fully characterized in the solid-state (X-Ray diffraction analysis) and in solution (EPR and UV-Vis spectroscopies). Potentiometric studies, combined with spectrometry, have also allowed us to determine their thermodynamic stability constants, confirming their high affinity for copper(II) cations. The kinetic inertness of the complexes has also been verified by acid-assisted dissociation experiments, enabling their use in 64Cu-PET imaging in mice for the first time. Indeed, the two ligands could be quantitatively radiolabeled under mild conditions, and the resulting 64Cu complexes have demonstrated excellent stability in serum. PET imaging demon-strated a set of features emerging from the combination of picolinates and phosphonate units: high stability in vivo, fast clear-ance from the body via renal elimination, and most interestingly, very low fixation in the liver. The latter is in contrast with what was observed for monopicolinate cyclam (te1pa), that had a non-negligible accumulation in the liver, owing probably to its different charge and lipophillicity. These results thus pave the way for the use of such phosphonated pyridine chelators for in vivo 64Cu-PET imaging.

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