A traditional painkiller as a probe for micro heterogeneity in 1-propanol-water mixtures (original) (raw)
Related papers
Indomethacin: A NSAID sensitive to micro heterogeneity in alcohol–water mixtures
Chemical Physics Letters, 2008
a b s t r a c t UV-vis absorption, steady state and time resolved fluorescence studies on the photo physical behavior of indomethacin, a traditional NSAID in binary water ethanol mixtures have been presented. Our results reveal that indomethacin can sense the micro heterogeneity in the binary mixtures forming ground state fluorescent complex with two predominant types of clusters viz. ethanol self-association clusters and hydrogen bonded water clusters.
A Comprehensive Spectroscopic Analysis of the Ibuprofen Binding with Human Serum Albumin, Part I
Pharmaceuticals, 2020
Human serum albumin (HSA) plays a fundamental role in the human body. It takes part in the transport of exogenic and endogenic substances, especially drugs. Ibuprofen (IBU) is one of the most commonly used non-steroidal anti-inflammatory drugs, used for pain relief, fever relief, and for anti-inflammatory purposes. The binding of ligands with HSA is a significant factor which determines the toxicity and the therapeutic dosages of these substances. The aim of this study was to compare the degree of ibuprofen binding with human serum albumin at various temperatures and protein solution pH values. In order to evaluate conformational changes in HSA caused by interaction with ibuprofen, spectrophotometric (first and second derivatives of the UV-VIS spectrum), and spectrofluorometric analyses were performed concerning the mutual interactions of IBU-HSA. The use of fluorescent spectroscopy allowed for recording fluorescent emissive spectra of HSA (5 × 10−6 mol/dm3) without and with the pre...
Solution thermodynamics of indomethacin in propylene glycol + water mixtures
Fuel and Energy Abstracts
The equilibrium solubilities of the analgesic drug indomethacin (IMC) in propylene glycol + water binary mixtures were determined at several temperatures from 293.15 to 313.15 K. The Gibbs energy, enthalpy, and entropy of solution and of mixing were obtained from these solubility data. The solubility was maximal in neat propylene glycol and very low in pure water at all the temperatures studied. A non-linear plot of soln H • vs. soln G • with negative slope from pure water up to 0.80 in mass fraction of propylene glycol and positive beyond this composition up to neat propylene glycol was obtained at the mean temperature, 303.15 K. This behavior is similar to those reported in the literature for this drug in 1,4-dioxane + water and ethanol + water mixtures. Accordingly, the driving mechanism for IMC solubility in the water-rich mixtures was the entropy, probably due to water-structure loss around non-polar moieties of the drug and for the propylene glycol-rich mixtures it was the enthalpy, probably due to its better solvation of the drug.
Improving Micromeritic Properties of Ibuprofen: An Agglomeration Approach
Bangladesh Pharmaceutical Journal, 2017
Ibuprofen is one of the common NSAIDs having poor water solubility, low dissolution, weak flow properties and reduced compressibility. These downsides of ibuprofen crystal upraise crucial challenges during development of a dosage form. The aim of this present work was to modify the physical form of ibuprofen by changing micromeritic properties. Seven different formulations of ibuprofen agglomerates such as F-1, F-2, F-3, F-4, F-5, F-6 and F-7 were prepared to convert the needle shaped ibuprofen crystals into agglomerates so that the desired micromeritic properties can be achieved. In this study, agglomerates of ibuprofen were prepared by Quasi emulsion solvent diffusion (QESD) method in association with two surfactants (sodium lauryl sulphateand Tween 80) at three different concentrations for each. The micromeritic properties of the prepared agglomerates were evaluated for bulk density, tapped density, Carr's index, Hausner's ratio, angle of repose along with the release behavior of agglomerates. From dissolution study, it was observed that the release of drug was directly proportional to the surfactant concentration. Here, it was also revealed that there was no interaction among ibuprofen and other excipients as evident from DSC and FTIR studies.
Analytica Chimica Acta, 2005
Molecules of electronically excited 2-[4-(dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one (a fluorescent probe) co-exist in the normal (N * ) and tautomeric (T * ) forms and emit radiation in different spectral regions. The positions (expressed in wave numbers, ν) and intensities (I) of the emission bands are strongly affected by the ability of the medium's molecules to participate in hydrogen bonding with the probe. In such cases, I depend on the concentration (over a certain range) or its base-10 logarithm (log) of the component interacting with the probe. These relationships form the basis for a quantitative assay of such compounds in binary mixtures. On the other hand, the log(I N* /I T* ) versus ν N* + ν T* or ν N* − ν T* relationships demonstrate unique features that can be used to distinguish components (alcohols) interacting with the probe and to quantify their contents. The prospects for the analytical application of these findings are outlined briefly.
Micro-heterogeneity versus clustering in binary mixtures of ethanol with water or alkanes
Physical Chemistry Chemical Physics, 2016
Ethanol is a hydrogen bonding liquid. When mixed in small concentrations with water or alkanes, it forms aggregate structures reminiscent of, respectively, the direct and inverse micellar aggregates found in emulsions, albeit at much smaller sizes. At higher concentrations, micro-heterogeneous mixing with segregated domains is found. We examine how different statistical methods, namely correlation function analysis, structure factor analysis and cluster distribution analysis, can describe efficiently these morphological changes in these mixtures. In particular, we explain how the neat alcohol pre-peak of the structure factor evolves into the domain pre-peak under mixing conditions, and how this evolution differs whether the co-solvent is water or alkane. This study clearly establishes the heuristic superiority of the correlation function/structure factor analysis to study the micro-heterogeneity, since cluster distribution analysis is insensitive to domain segregation. Correlation functions detect the domains, with a clear structure factor pre-peak signature, while the cluster techniques detect the cluster hierarchy within domains. The main conclusion is that, in micro-segregated mixtures, the domain structure is a more fundamental statistical entity than the underlying cluster structures. These findings could help better understand comparatively the radiation scattering experiments, which are sensitive to domains, versus the spectroscopy-NMR experiments, which are sensitive to clusters. Motivation This work illustrates, perhaps for the first time, the profound difference between clustering and micro-segregation in complex liquids, despite the fact that clustering is at the origin of microsegregation. This difference allows us to attribute a heuristic importance to some physical observables (structure factors) with respect to others (cluster distribution). Although our work is theoretical, our findings should impact the experimental ones, related to each of these observable-radiation scattering versus spectroscopy and NMR, as well as favour a deeper understanding of molecular association in soft-matter.
The Journal of Chemical Physics, 2014
We investigated the 1-propynyl (CH 3 CC; X 2 A 1) plus acetylene/acetylene-d 2 (HCCH/DCCD; X 1 Σ g +) under single-collision conditions using the crossed molecular beams method. The reaction was found to produce C 5 H 4 plus atomic hydrogen (H) via an indirect reaction mechanism with a reaction energy of −123 ± 18 kJ mol −1. Using the DCCD isotopologue, we confirmed that the hydrogen atom is lost from the acetylene reactant. Our computational analysis suggests the reaction proceeds by the barrierless addition of the 1-propynyl radical to acetylene, resulting in C 5 H 5 intermediate(s) that dissociate preferentially to methyldiacetylene (CH 3 CCCCH; X 1 A 1) via hydrogen atom emission with a computed reaction energy of −123 ± 4 kJ mol −1. The barrierless nature of this reaction scheme suggest the 1-propynyl radical may be a key intermediate in hydrocarbon chain growth in cold molecular clouds like TMC-1 where methyl-substituted (poly)acetylenes are known to exist.
Scientific Reports, 2016
The infrared-active (IR) vibrational mode of ethanol (EtOH) associated with the asymmetrical stretching of the CC -O bond in pico-liter volumes of EtOH-water binary mixtures is calorimetrically measured using photothermal microfluidic cantilever deflection spectroscopy (PMCDS). IR absorption by the confined liquid results in wavelength dependent cantilever deflections, thus providing a complementary response to IR absorption revealing a complex dipole moment dependence on mixture concentration. Solvent-induced blue shifts of the CC -O asymmetric vibrational stretch for both anti and gauche conformers of EtOH were precisely monitored for EtOH concentrations ranging from 20-100% w/w. Variations in IR absorption peak maxima show an inverse dependence on induced EtOH dipole moment (μ) and is attributed to the complex clustering mechanism of EtOH-water mixtures.
Cloud point, fluorimetric and 1H NMR studies of ibuprofen-polymer systems
Journal of Molecular Structure, 2014
h i g h l i g h t s Much interest has been shown on interactions between amphiphilic drugs and polymers in a variety of fields, such as pharmaceuticals and bioscience. The 1 H NMR spectroscopy was used in the present investigation to probe the molecular investigation between ibuprofen and polymers. Aggregation number depends strongly on polymer percentage. g r a p h i c a l a b s t r a c t Average aggregation numbers of the total ensemble of ibuprofen micelles formed in solution, N agg , as a function of the polymer percentage.