Organic acids as co-formers for co-amorphous systems – Influence of variation in molar ratio on the physicochemical properties of the co-amorphous systems

2018 ◽  
Vol 131 ◽  
pp. 25-32 ◽  
Author(s):  
Wenqi Wu ◽  
Hiroshi Ueda ◽  
Korbinian Löbmann ◽  
Thomas Rades ◽  
Holger Grohganz
2019 ◽  
Author(s):  
Chem Int

Biodiesel produced by transesterification process from vegetable oils or animal fats is viewed as a promising renewable energy source. Now a day’s diminishing of petroleum reserves in the ground and increasing environmental pollution prevention and regulations have made searching for renewable oxygenated energy sources from biomasses. Biodiesel is non-toxic, renewable, biodegradable, environmentally benign, energy efficient and diesel substituent fuel used in diesel engine which contributes minimal amount of global warming gases such as CO, CO2, SO2, NOX, unburned hydrocarbons, and particulate matters. The chemical composition of the biodiesel was examined by help of GC-MS and five fatty acid methyl esters such as methyl palmitate, methyl stearate, methyl oleate, methyl linoleate and methyl linoleneate were identified. The variables that affect the amount of biodiesel such as methanol/oil molar ratio, mass weight of catalyst and temperature were studied. In addition to this the physicochemical properties of the biodiesel such as (density, kinematic viscosity, iodine value high heating value, flash point, acidic value, saponification value, carbon residue, peroxide value and ester content) were determined and its corresponding values were 87 Kg/m3, 5.63 Mm2/s, 39.56 g I/100g oil, 42.22 MJ/Kg, 132oC, 0.12 mgKOH/g, 209.72 mgKOH/g, 0.04%wt, 12.63 meq/kg, and 92.67 wt% respectively. The results of the present study showed that all physicochemical properties lie within the ASTM and EN biodiesel standards. Therefore, mango seed oil methyl ester could be used as an alternative to diesel engine.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Venkata Deepthi Vemuri ◽  
Srinivas Lankalapalli

Abstract Background The meager physicochemical properties like low solubility and low dissolution rate of rosuvastatin calcium remain as an obstruction for formulation development. In the present work, we explore the evolution of rosuvastatin cocrystal, which may offer the synergetic physico-chemical properties of the drug. Cocrystal crafting depends on two possible intermolecular interactions; heteromeric and the homomeric selection of compounds with complementary functional groups are contemplated as a possible cause of supramolecular synthons in cocrystal formation. Specifically, cocrystals of rosuvastatin with l-asparagine and l-glutamine with molar ratio (1:1) were fabricated by using slow solvent evaporation and slow evaporation techniques. Novel cocrystals of rosuvastatin-asparagine (RSC-C) and rosuvastatin-glutamine (RSC-G) cocrystals obtained by slow solvent evaporation were utilized for preliminary investigation and further scale-up was done by using the solvent evaporation technique. Results The novel cocrystals showed a new characteristic of powder X-ray diffraction, thermograms of differential scanning calorimetry, 1H liquid FT-NMR spectra, and scanning electron microscopy. These results signify the establishment of intermolecular interaction within the cocrystals. In both the novel cocrystals, rosuvastatin was determined to be engaged in the hydrogen bond interaction with the complementary functional groups of l-asparagine and l-glutamine. Compared with the pure rosuvastatin, RSC-C and RSC-G cocrystal showed 2.17-fold and 1.60-fold improved solubility respectively. The dissolution test showed that the RSC-C and RSC-G cocrystal exhibited 1.97-fold and 1.94-fold higher dissolution rate than the pure rosuvastatin in pH6.8 phosphate buffer respectively. Conclusion Modulation in the chemical environment, improvement in the solubility, and dissolution rate demonstrated the benefit of co-crystallization to improve the physicochemical properties of the drug. Graphical abstract


2007 ◽  
Vol 87 (7) ◽  
pp. 1207-1214 ◽  
Author(s):  
Fernando Martínez-Bustos ◽  
Silvia Lorena Amaya-Llano ◽  
J Antonio Carbajal-Arteaga ◽  
Yoon Kil Chang ◽  
José de J Zazueta-Morales

1992 ◽  
Vol 55 (11) ◽  
pp. 893-898 ◽  
Author(s):  
TAKESHI SUZUKI ◽  
FERGUS M. CLYDESDALE ◽  
TIRA PANDOLF

The effect of six organic acids, ascorbic, citric, fumaric, lactic, malic, and succinic, alone and in combination, at a 1:1.9 molar ratio (Fe+2:ligand) on the solubility of iron was evaluated in the presence of lignin under simulated gastrointestinal pH conditions. The enhancing effect, evaluated under two systems of preparation at two pH values, was in the following order: citric>malic>ascorbic>lactic,fumaric>succinic. Citric acid solubilized 80 and 81% of iron under both pH conditions. When ascorbic acid was mixed with fumaric, lactic, and succinic acids, a higher percentage of soluble iron was retained than with these three acids alone. In the case of citric and malic acids, the addition of ascorbic acid reduced the soluble iron. The percentage of soluble iron obtained when prepared at the endogenous pH (2.5–3.1) was higher than that at pH 5.5. These results indicated that ascorbate bound less iron in a soluble form than citrate or malate but more than fumarate, lactate, or succinate. Also, combinations of citric with malic acid did not demonstrate a synergistic effect.


Author(s):  
Xiaoyu Wang ◽  
Tinghao Jia ◽  
Lun Pan ◽  
Qing Liu ◽  
Yunming Fang ◽  
...  

AbstractThe development of advanced air transportation has raised new demands for high-performance liquid hydrocarbon fuels. However, the measurement of fuel properties is time-consuming, cost-intensive, and limited to the operating conditions. The physicochemical properties of aerospace fuels are directly influenced by chemical composition. Thus, a thorough investigation should be conducted on the inherent relationship between fuel properties and composition for the design and synthesis of high-grade fuels and the prediction of fuel properties in the future. This work summarized the effects of fuel composition and hydrocarbon molecular structure on the fuel physicochemical properties, including density, net heat of combustion (NHOC), low-temperature fluidity (viscosity and freezing point), flash point, and thermal-oxidative stability. Several correlations and predictions of fuel properties from chemical composition were reviewed. Additionally, we correlated the fuel properties with hydrogen/carbon molar ratios (nH/C) and molecular weight (M). The results from the least-square method implicate that the coupling of H/C molar ratio and M is suitable for the estimation of density, NHOC, viscosity and effectiveness for the design, manufacture, and evaluation of aviation hydrocarbon fuels.


Author(s):  
TEJASWINI MANE ◽  
MUKESH MOHITE

Objective: Most of the drugs are relevant to BSC class II and class IV having solubility problems. Cocrystallization of drug with conformer is an immense approach used to explore the physicochemical properties of drug. The objective of the present work was to design formulate and evaluate the drug cocrystals of poorly soluble drug apremilast (APR) with saccharin. Methods: Cocrystals of APR were prepared using the solvent evaporation technique. The saturated solubility study and in vitro dissolution study of cocrystals were carried out. The prepared cocrystals were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The topical gel of APR cocrystals was formulated optimized and evaluated using three-level factorial design. Results: The cocrystals of APR were prepared in 1:1 molar ratio with saccharin. APR cocrystals showed the improvement in solubility and dissolution as compared to pure APR. The formation of cocrystals was confirmed from change in endothermic peak of DSC and from shifting of FTIR spectra of cocrystals. Crystallinity of cocrystal was confirmed from XRD pattern and noteworthy change in 2θ values of the intense peak. The topical gel of APR cocrystals was formulated and optimized using three-level factorial design using Carbapol-940 and hydroxypropyl methylcellulose (HPMC) as a gelling agent. Conclusion: The cocrystals with altered physicochemical properties of APR were prepared with saccharin and formulated as a topical gel to overcome the problems related to oral administration.


2019 ◽  
Vol 77 (9) ◽  
pp. 4469-4488 ◽  
Author(s):  
Umesh Somaji Waware ◽  
A. M. S. Hamouda ◽  
Dipanwita Majumdar

Abstract Polyaniline (PA), the versatile conducting polymer, owing to its tunable optoelectronic properties, facile preparation methodology and reversible redox behavior, has elicited much interest among current researchers, particularly in the fields of energy generation storage devices, protective coatings and electrochemical sensors. However, its commercialization has been much restricted due to low solution processability and thermal stability. Recent studies reveal that the above-mentioned challenges can effectively be addressed by copolymerization of PA with suitable components. In addition, the properties of copolymers could be modified and tuned by varying the monomer ratios. Thus, the present work is concerned with the fabrication of poly(aniline-co-3-nitroaniline) with varying compositions obtained by in situ oxidative copolymerization of aniline and 3-nitroaniline by altering the molar ratio of monomers. Optimization of the physicochemical properties such as UV–visible absorption, solubility, thermal stability, electrical conductivity and dielectric signatures, particle size and morphology was achieved by varying the composition of monomeric substituents in these copolymers. Smoother morphology of the copolymer films was revealed by morphological studies via AFM technique and supported by particle size distribution study. The physicochemical trends demonstrated that proper proportions of nitro (–NO2) group in the polymer chain are essential to achieve desired optimal physicochemical properties. Therefore, copolymers are ideally appropriate for multifaceted applications and would promote wider usage of conjugated polymers in various fields of organic-based optoelectronic as well as energy storage devices in the near future.


Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 675 ◽  
Author(s):  
Jinbo Ouyang ◽  
Jian Chen ◽  
Limin Zhou ◽  
Fangze Han ◽  
Xin Huang

To improve the physicochemical properties of valnemulin (VLM), different solid forms formed by VLM and organic acids, including tartaric acid (TAR), fumaric acid (FUM), and oxalic acid (OXA), were successfully prepared and characterized by using differential scanning calorimetry (DSC), scanning electron microscope (SEM), X-ray powder diffraction (XRPD), and Fourier-transform infrared spectroscopy (FT-IR). The excess enthalpy Hex between VLM and other organic acids was calculated by COSMOthermX software and was used to evaluate the probability of forming multi-component solids between VLM and organic acids. By thermal analysis, it was confirmed that multi-component solid forms of VLM were thermodynamically more stable than VLM itself. Through dynamic vapor sorption (DVS) experiments, it was found that three multi-component solid forms of VLM had lower hygroscopicity than VLM itself. Furthermore, the intrinsic dissolution rate of VLM and its multi-component forms was determined in one kind of acidic aqueous medium by using UV-vis spectrometry. It was found that the three multi-component solid forms of VLM dissolved faster than VLM itself.


Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 607
Author(s):  
Muthia Elma ◽  
Anna Sumardi ◽  
Adhe Paramita ◽  
Aulia Rahma ◽  
Aptar Eka Lestari ◽  
...  

The physicochemical properties of organo-silica xerogels derived from organo catalyst were pervasively investigated, including the effect of one-step catalyst (citric acid) and two-step catalyst (acid-base), and also to observe the effect of sol pH of organo-silica xerogel toward the structure and deconvolution characteristic. The organo-silica xerogels were characterized by FTIR, TGA and nitrogen sorption to obtain the physicochemical properties. The silica sol–gel method was applied to processed materials by employing TEOS (tetraethyl orthosilicate) as the main precursor. The final molar ratio of organo-silica was 1:38:x:y:5 (TEOS:ethanol: citric acid: NH3:H2O) where x is citric acid concentration (0.1–10 × 10−2 M) and y is ammonia concentration (0 to 3 × 10−3 M). FTIR spectra shows that the one-step catalyst xerogel using citric acid was handing over the higher Si-O-Si concentration as well as Si-C bonding than the dual catalyst xerogels with the presence of a base catalyst. The results exhibited that the highest relative area ratio of silanol/siloxane were 0.2972 and 0.1262 for organo catalyst loading at pH 6 and 6.5 of organo-silica sols, respectively. On the other hand, the organo-silica matrices in this work showed high surface area 546 m2 g−1 pH 6.5 (0.07 × 10−2 N citric acid) with pore size ~2.9 nm. It is concluded that the xerogels have mesoporous structures, which are effective for further application to separate NaCl in water desalination.


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