Benzoate Molecules Research Articles

Structure and Phase Analysis of a Liquid Crystal Benzoate Molecule — Theoretical Approach

Structure and Phase Analysis of a Liquid Crystal Benzoate Molecule — Theoretical Approach

Development of a new affinity chromatography method for purification of horseradish peroxidase enzyme.

In this study, benzohydroxamic acid molecules were synthesized from methyl 4-amino-2-methoxy, methyl 4-amino-3-nitro, methyl 4-amino-3-methyl, and methyl 4-amino-3-chloro benzoate molecules, and the horseradish peroxidase (HRP) enzyme was purified in one step using the affinity chromatography technique for the first time. The IC50 and Ki values for the 4-amino 3-methyl benzohydroxamic acid molecule were 0.136 and 0.132 ± 0.054μM, respectively, while the IC50 and Ki values for the 4-amino-3-nitro benzohydroxamic acid molecule were 56.00 and 51.90 ± 9.90μM, respectively. It was found that the IC50 and Ki values for the 4-amino-3-chloro benzohydroxamic acid molecule were 218.33 and 175.67 ± 43.78μM, respectively, whereas the IC50 and Ki values for the 4-amino-2-methoxy benzohydroxamic acid molecule were 306.00 and 218.00 ± 68.80μM, respectively. The HRP enzyme was synthesized from 4-amino-2-methoxy hydroxamic acid column with a 35.97% yield 601.13 times, 4-amino-3-nitro hydroxamic acid column, with a 14.00% yield 404.11 times, 4-amino-3-methyl hydroxamic acid column with an 8.70% yield 394.88 times, and 4-amino-3-chloro hydroxamic acid column with a 4.48% yield 284.85 times. Thus, the HRP enzyme was purified in a single step with hydroxamic acids, and its molecular weight was found to be 44kDa. The optimum pH was 8.0, the optimum temperature was 15°C, and the optimum ionic strength was 0.4M for the purified HRP enzyme.

Synthesis and crystal structure of the copper (II) carboxylate with 2,2-bipyridine, [Cu(4-mba)2(bipy)(H2O)

The new Cu(II) carboxylate complex, aqua(2,2'-bipyridine-κ2N,N')bis(4-methylbenzoato-κO)copper(II) [Cu(4-mba)2(bipy)(H2O)] (4-mba: 4-methylbenzoate, bipy: 2,2'-bipyridine) was synthesized, and the molecular structure of the complex was characterized by the single crystal X-ray diffraction technique. The X-ray diffraction analysis indicated that the asymmetric unit comprises an independent molecule. Crystal data for [Cu(4-meb)2(2,2-bipy)(H2O)]: Triclinic, space group P-1 (no. 2), a = 7.0452(13) Å, b = 11.260(2) Å, c = 16.635(3) Å, α = 103.543(7)°, β = 91.002(7)°, γ = 104.106(6)°, V = 1240.4(4) Å3, Z = 2, T = 296 K, μ(MoKα) = 0.918 mm-1, Dcalc = 1.360 g/cm3, 51364 reflections measured (5.054° ≤ 2Θ ≤ 57.38°), 6258 unique (Rint = 0.0398, Rsigma = 0.0284) which were used in all calculations. The final R1 was 0.0392 (I > 2σ(I)) and wR2 was 0.1021 (all data). The Cu(II) ion was found to be coordinated with two nitrogen atoms of the 2,2'-bipyridine ligand, two oxygen atoms of the 4-methyl benzoate molecule, and one oxygen atom of the aqua ligand. In the three-dimensional supramolecular architecture, molecules are connected through pairs of O-H···O and C-H···O intermolecular interactions, consisting of chains. The molecule also demonstrates Cg···Cg intermolecular interactions between six-membered rings of 2,2'-bipyridine.

First (e,e) coincidence measurements on solvated sodium benzoate in water using a magnetic bottle time-of-flight spectrometer.

Understanding the mechanisms of X-ray radiation damage in biological systems is of prime interest in medicine (radioprotection, X-ray therapy…). Study of low-energy rays, such as soft-X rays and light ions, points to attribute their lethal effect to clusters of energy deposition by low-energy electrons. The first step, at the atomic or molecular level, is often the ionization of inner-shell electrons followed by Auger decay in an aqueous environment. We have developed an experimental set-up to perform electron coincidence spectroscopy on molecules in a water micro-jet. We present here the first results obtained on sodium benzoate solutions, irradiated at the oxygen and carbon K-edges.

Theoretical (B3lyp) and Spectroscopic (Ft-Ir, 1h-Nmr and 13c-Nmr) Investigation of 2- Methoxy-6-[(3-(P-Methylbenzyl)-4,5-Dihydro-1h-1,2,4-Triazol-5-One-4-Yl)-Azomethin]-Phenyl Benzoate

Density functional theory (DFT) is an inexpensive approach used to study the molecular structure, many theoretical properties, biological activities and electronic properties of simple and complex compounds. In this study, the all quantum chemical studies of 2-Methoxy-6-[(3-(p-methylbenzyl)-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl)-azomethin]-phenyl Benzoate molecule were calculated using the DFT(B3LYP) method with 6-311++G(d,p) basis set. For use in all these computational processes, initially the molecule was optimized. Thus, the most stable state of atoms was reached. Then, the calculations of carbon-13 and proton-NMR isotropic shift values were performed in the solvent (DMSO) and gaseous with "the gauge-independent atomic orbital" (GIAO). Infrared (FT-IR) vibration frequency values were calculated from the Veda4f program. The theoretical vibration frequency values were compared with the experimental IR values. Experimental data obtained from the literature. In addition, the electronic properties (chemical hardness and softness, ionization potential (I), electronegativity (χ), electron affinity (A), electrophilic and nucleophilic index), ΔEg energy gap, HOMO-LUMO energies, the geometric properties (bond angle and length), the thermodynamic properties (thermal capacity (CV), entropy (S), thermal energy (E), dipole moment, mulliken atomic charge values, molecular electron potential (MEP), total density and contour surface maps and the total energy of the molecule were determined.

Polydopamine-Coated Poly-Lactic Acid Aerogels as Scaffolds for Tissue Engineering Applications.

Poly-L-lactic acid (PLLA) aerogel-based scaffolds were obtained from physical PLLA gels containing cyclopentanone (CPO) or methyl benzoate (BzOMe) molecules. An innovative single step method of solvent extraction, using supercritical CO2, was used to achieve cylindrical monolithic aerogels. The pore distribution and size, analyzed by SEM microscopy, were found to be related to the crystalline forms present in the physical nodes that hold the gels together, the stable α’-form and the metastable co-crystalline ε-form, detected in the PLLA/BzOMe and PLLA/CPO aerogels, respectively. A higher mechanical compressive strength was found for the PLLA/CPO aerogels, which exhibit a more homogenous porosity. In vitro biocompatibility tests also indicated that monolithic PLLA/CPO aerogels exhibited greater cell viability than PLLA/BzOMe aerogels. An improved biocompatibility of PLLA/CPO monolithic aerogels was finally observed by coating the surface of the aerogels with polydopamine (PDA) obtained by the in situ polymerization of dopamine (DA). The synergistic effect of biodegradable polyester (PLLA) and the biomimetic interface (PDA) makes this new 3D porous scaffold, with porosity and mechanical properties that are tunable based on the solvent used in the preparation process, attractive for tissue engineering applications.

DETERMINATION OF POTASSIUM SORBATE AND SODIUM BENZOATE IN NON-ALCOHOLIC DRINKS WITH PIEZOSENSORS BASED ON MOLECULAR-IMPRINTED POLYMERS

Preservatives such as potassium sorbate and sodium benzoate are commonly used in the food industry. It is necessary to control the content of preservatives in food products, because exceeding the permissible limit of the concentration can affect human health. To determine the contents of potassium sorbate and sodium benzoate in non-alcoholic drinks, a piezoelectric sensor based on molecularly imprinted polymers (MIPs) was used. Molecularly imprinted polymers were synthesized by copolymer of dianhydride 1,2,4,5-benzenetetracarboxylic acid with 4,4'-diaminodiphenyl oxide in N,N-dimethylformamide in the presence of a template by the non-covalent imprinting method. To assess the selectivity and ability to recognize target molecules, the values of the imprinting factor and the selectivity coefficient of the sensors were calculated. Based on the data obtained, it was found that molecularly imprinted polymers with imprints of potassium sorbate and sodium benzoate had better selectivity and ability to recognize target potassium sorbate and sodium benzoate molecules than polymers without imprints. In this study, the ranges of determined concentrations (5-500 mg/l) and detection limits of potassium sorbate (1.6 mg/l) and sodium benzoate (2 mg/l) were experimentally established. The results of the determination of potassium sorbate and sodium benzoate in non-alcoholic drinks by piezosensors were compared with the spectrophotometric method. It had been established that the difference in the determination results did not exceed 10%. Thus, the possibility of using piezosensor based on molecularly imprinted polymers with imprints of potassium sorbate and sodium benzoate for their determination in non-alcoholic drinks has been established.

Coupling a magnetic bottle multi-electron spectrometer with a liquid micro-jet device: a comprehensive study of solvated sodium benzoate at the O 1 s threshold

We have developed a magnetic bottle time-of-flight electron-electron coincidence spectrometer to perform measurements on solvated molecules in a liquid micro-jet. We present here the first results obtained after ionization of the oxygen 1s inner-shell of sodium benzoate molecules and show the possibilities to filter out the electron signal arising from the liquid phase from the signal of water molecules in the gas phase. Both photoelectrons and Auger electrons spectra (unfiltered and filtered) are presented.

Морфология поверхности полимеров с молекулярными отпечатками на основе полиимида

В работе получены полимеры с молекулярными отпечатками бензоата натрия на поверхности электродов пьезосенсоров. Широкое использование консервантов в пищевой промышленности спо-собствует развитию экспресс-методов их анализа модифицированными пьезосенсорами. Цель работы: анализ морфологии поверхности полимеров с молекулярными отпечатками, полученных на основе полиимида методом сканирующей силовой микроскопии.Полимеры с молекулярными отпечатками получены на основе сополимера диангидрида 1,2,4,5-бензолтетракарбоновой кислоты с 4,4'-диаминодифенилоксидом, производства ОАО МИПП НПО «Пластик», г. Москва. В качестве темплата использовали бензоат натрия. Предполимеризацион-ную смесь наносили на поверхность электродов пьезосенсоров шпателем или методом штампования. Проводили термоимидизацию в сушильном шкафу в два этапа: первый этап проходил при 80oС, вто-рой – при 120oС. После полимеризации пленки, сенсоры охлаждали до комнатной температуры, затем помещали их в дистиллированную воду на 24 часа для удаления шаблона.Исследование морфологии поверхности полученных полимерных пленок проводили с помо-щью сканирующего силового микроскопа (ССМ) «Solver P47 PRO» производства ЗАО «НТ-МДТ» в полуконтактном режиме зондом NSG03 с жесткостью 1.74 Н/м. Обработку изображений проводили программой ФемтоСкан-001.Анализ морфологии поверхности пленок показал, что нанесение предполимеризационной смеси штампом приводит к формированию более равномерной поверхности с перепадом высот от 1.4 до 2.6 нм. Использование шпателя приводит к формированию более шероховатой поверхности с вы-сотами в диапазоне 0.9-3.4 нм. Таким образом предложенная методика нанесения смеси является пер-спективной поскольку позволяет получать более воспроизводимые по толщине и шероховатости по-верхности, что позволит повысить точность анализа веществ пьезосенсорами модифицированными этими полимерами.При этом следует учесть, что при формировании полимерной пленки молекулы-шаблона ча-стично или полностью заглубляются в матрицу полимера, а также располагаются на ее поверхности, образуя глобулярные структуры. Экстракция шаблона с поверхности полимера приводит к появлению полостей комплементарных молекулам бензоата натрия.

The Impact of Salinity on the Interfacial Structuring of an Aromatic Acid at the Calcite/Brine Interface: An Atomistic View on Low Salinity Effect.

This study aims to elucidate the impact of salinity on the interactions governing the adsorption of polar aromatic oil compounds onto calcite. To this end, molecular dynamics simulations were employed to assess adsorption of a model polar organic molecule (deprotonated benzoic acid, benzoate) on the calcite surface in NaCl brines of different concentration levels, namely, deionized water (DW), low-salinity water (LS, 5000 ppm), and sea water (SW; 45,000 ppm). Calcite was found to be completely covered by several well-ordered water layers. The top hydration layer is very compact and prevents direct adsorption of benzoates onto the substrate. Instead, Na+ ions form a distinct positively charged layer by adhering on the calcite substrate through inner-sphere complexion mode. Cl- ions mostly lodge on top of the adsorbed sodium cations, forming a negatively charged layer. The distribution of ions at the calcite/brine interface thus exhibits the features of an electrical double layer, composed of a Stern-like positive layer followed by a negative one. The positive charged layer attracts benzoates toward the surface. As such, the sodium ions attached onto the calcite can act as adsorption sites to connect benzoates to the surface. By increasing the salinity, more Na+ ions adsorb onto the calcite surface, and the density of benzoate molecules at the interface is enhanced as a result of more Na+ bridging ions. The monotonic salinity-dependent adsorption of benzoate molecules on calcite offers a mechanism driving additional oil recovery upon injection of diluted brine into subsurface carbonate reservoirs.

A New Family of Heterometallic LnIII[12-MCFeIIIN(shi)-4] Complexes: Syntheses, Structures and Magnetic Properties

A new family of LnIII [12-Metallacrown-4] compounds of formulas (C5H6N) [LnFe4(shi)4(C6H5COO)4(Py)4]·3.5Py [Ln = EuIII (1); GdIII (2); TbIII (3); DyIII (4); and, H3shi = salicylhydroxamic acid] were obtained through one-pot reactions with H3shi, Fe(NO3)3·9H2O, and, Ln(NO3)3·6H2O as reagents. Single-crystal X-ray analyses show that they are isostructural and have the similar [12-MCFeIII N(shi)-4] core, with four benzoate molecules bridging the central LnIII ion to the ring FeIII ions. The negative charge of the 12-MC-4 metallacrown is balanced by one pyridinium cation, which forms the hydrogen bond with an adjacent solvent pyridine molecule. Magnetic measurements demonstrate antiferromagnetic coupling interactions and field-induced slow magnetic relaxation in complex 4.

Regulating Higher-Order Organization through the Synergy of Two Self-Sorted Assemblies.

The extracellular matrix (ECM) is the natural fibrous scaffold that regulates cell behavior in a hierarchical manner. By mimicking the dynamic and reciprocal interactions between ECM and cells, higher-order molecular self-assembly (SA), mediated through the dynamic growth of scaffold-like nanostructures assembled by different molecular components, was developed. Designed and synthesized were two self-sorted coumarin-based gelators, a peptide molecule and a benzoate molecule, which self-assemble into nanofibers and nanobelts, respectively, with different dynamic profiles. Upon the dynamic growth of the fibrous scaffold assembled from peptide gelators, nanobelts assembled from benzoate gelators transform into a layer-by-layer nanosheet, reaching ninefold increase in height. By using light and an enzyme, the spatial-temporal growth of the scaffold can be modified, leading to in situ height regulation of the higher-order architecture.

Regulating Higher‐Order Organization through the Synergy of Two Self‐Sorted Assemblies

AbstractThe extracellular matrix (ECM) is the natural fibrous scaffold that regulates cell behavior in a hierarchical manner. By mimicking the dynamic and reciprocal interactions between ECM and cells, higher‐order molecular self‐assembly (SA), mediated through the dynamic growth of scaffold‐like nanostructures assembled by different molecular components, was developed. Designed and synthesized were two self‐sorted coumarin‐based gelators, a peptide molecule and a benzoate molecule, which self‐assemble into nanofibers and nanobelts, respectively, with different dynamic profiles. Upon the dynamic growth of the fibrous scaffold assembled from peptide gelators, nanobelts assembled from benzoate gelators transform into a layer‐by‐layer nanosheet, reaching ninefold increase in height. By using light and an enzyme, the spatial–temporal growth of the scaffold can be modified, leading to in situ height regulation of the higher‐order architecture.

The emergence of aqueous chemiluminescence: new promising class of phenoxy 1,2-dioxetane luminophores.

The majority of known chemiluminescent compounds produce light through oxidation-dependent mechanisms. The unique notion of triggering chemiluminescence by a chemical reaction other than oxidation was first introduced by Schaap in 1987 with the development of chemically and enzymatically activated phenoxy-dioxetanes. Such dioxetanes are distinctive among chemiluminescent molecules since the oxidized high-energy species, the dioxetane, is stable for years at room temperature. Light emission is selectively activated by deprotection of the phenol-protecting group. The chemiluminescence quantum yields of such dioxetanes are relatively high in organic solvents like DMSO. In aqueous solution, however, light emission efficiency drops by approximately 10 000-fold due to energy loss to water molecules. As we sought to understand the low light emission efficiency in water, we realized that the dioxetane chemiexcitation leads to the release of an excited state benzoate molecule, which is a very weak emitter under aqueous conditions. Thus, we reasoned that emission in aqueous solution could be enhanced, if the emissive nature of the excited benzoate formed in water is improved. Introduction of an electron-withdrawing acrylic group at the ortho position of the phenol donor resulted in an excited benzoate species that emits light with high efficiency in aqueous solutions. A striking 3000-fold increase in chemiluminescence emission was observed by simply using an acrylonitrile substituent on the dioxetane probe. For the first time, scientists now have an effective single-entity chemiluminescent probe that can be used to evaluate biological processes. This discovery promoted us to develop numerous highly efficient chemiluminescent probes for detection of different enzymes and analytes in aqueous solution. We anticipate that further studies in this direction will lead to even better chemiluminescence probes with quantum yield emissions that are even higher than that of the luciferin/luciferase system. In this Feature Article, we describe the insights that led us to develop these unprecedented luminophores and the historical perspective that led to the current generation of chemiluminescent phenoxy-dioxetane probes.

Chemical Reaction of Benzoic Acid with Ge(100): Effect of a Phenyl Substituent

The adsorption of benzoic acid onto Ge (100) was investigated using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. At room temperature, the on-top bidentate structure of benzoate molecules on Ge(100) was the most favorable. After annealing at 420 K, nearly all of the adsorption structures changed into on-top structures. The preference for the on-top structure could be explained in terms of the thermodynamic stability and kinetic considerations. Simulated STM images of the stable configuration could explain the experimentally observed images. The surface ordering of the adsorbed benzoic acid molecules was characterized through an appropriate application of hot surface dosing and annealing of the Ge surface at different coverages. Surface ordering along the dimer row direction was observed at a lower coverage. At saturation coverage, ordered lines with several adsorbed benzoic acid molecules formed along both the dimer row and the dimer direction and were stabilized th...

Solution Deposition of Self-Assembled Benzoate Monolayers on Rutile (110): Effect of π–π Interactions on Monolayer Structure

High-quality, self-assembled benzoate monolayers were synthesized on rutile (110) using simple aqueous reactions. Sputtering and annealing cycles, which create surface and subsurface defects, were not needed. The monolayers were hydrophobic and remained largely contaminant free during exposures to laboratory air for tens of minutes. During this period, infrared spectroscopy showed that the monolayers did not spontaneously adsorb airborne hydrocarbons or other adventitious aliphatic species. Scanning tunneling microscopy (STM) images, infrared and X-ray photoemission spectra, Monte Carlo simulations, and ab initio calculations were all consistent with benzoate molecules adopting an edge-to-face ring geometry with their four nearest neighbors—a tetrameric bonding geometry. This bonding is further stabilized by a pairing interaction between adjacent benzoate molecules, a pairing that has previously been interpreted as dimerization. The coexistence of paired and unpaired regions of the monolayer is consistent...

Ga(3+)/Ln(3+) Metallacrowns: A Promising Family of Highly Luminescent Lanthanide Complexes That Covers Visible and Near-Infrared Domains.

Luminescent lanthanide(III)-based molecular scaffolds hold great promises for materials science and for biological applications. Their fascinating photophysical properties enable spectral discrimination of emission bands that range from the visible to the near-infrared (NIR) regions. In addition, their strong resistance to photobleaching makes them suitable for long duration or repeated biological experiments using a broad range of sources of excitation including intense and focalized systems such as lasers (e.g., confocal microscopy). A main challenge in the creation of luminescent lanthanide(III) complexes lies in the design of a ligand framework that combines two main features: (i) it must include a chromophoric moiety that possesses a large molar absorptivity and is able to sensitize several different lanthanide(III) ions emitting in the visible and/or in the near-infrared, and (ii) it must protect the Ln(3+) cation by minimizing nonradiative deactivation pathways due to the presence of -OH, -NH and -CH vibrations. Herein, a new family of luminescent Ga(3+)/Ln(3+) metallacrown (MC) complexes is reported. The MCs with the general composition [LnGa4(shi)4(C6H5CO2)4(C5H5N) (CH3OH)] (Ln-1, Ln = Sm(3+)-Yb(3+)) were synthesized in a one pot reaction using salicylhydroxamic acid (H3shi) with Ga(3+) and Ln(3+) nitrates as reagents. The molecular structure of [DyGa4(shi)4(C6H5CO2)4(C5H5N) (CH3OH)] was obtained by X-ray analysis of single crystals and shows that the complex is formed as a [12-MCGa(III)shi-4] core with four benzoate molecules bridging the central Dy(3+) ion to the Ga(3+) ring metals. The powder X-ray diffraction analysis demonstrates that all other isolated complexes are isostructural. The extended analysis of the luminescence properties of these complexes, excited by the electronic states of the chromophoric ligands, showed the presence of characteristic, sharp f-f transitions that can be generated not only in the NIR (Sm, Dy, Ho, Er, Yb) but also in the visible (Sm, Eu, Tb, Dy, Tm). All Ln-1 complexes possess very high quantum yield values with respect to other literature compounds, indicating a good sensitization efficiency of the [12-MCGa(III)shi-4] scaffold. Especially, as of today, the Yb-1 complex exhibits the highest NIR quantum yield reported for a lanthanide(III) complex containing C-H bonds with a value of 5.88(2)% in the solid state. This work is a significant step forward toward versatile, easily prepared luminescent lanthanide(III) complexes suitable for a variety of applications including highly in demand biological imaging, especially in the NIR domain.

Crystal structures of (±)-(1SR,5SR,6SR,7SR,10SR,11SR,13RS,14SR)-13-hy-droxy-7-meth-oxy-meth-oxy-11,15,18,18-tetra-methyl-3-oxo-2,4-dioxa-tetra-cyclo-[12.3.1.0(1,5).0(6,11)]octa-dec-15-en-10-yl benzoate, its 13-epimer and 13-one derivative.

The title compounds, C29H38O8·0.25C5H12, (A), C29H38O8, (B), and C29H36O8, (C), are tetra-cyclic benzoates possessing a taxane skeleton with a fused dioxolane ring as the core structure. In the asymmetric unit of (A), there are two independent benzoate mol-ecules (A and A') and a half mol-ecule of solvent pentane disordered about an inversion center. The mol-ecular conformations of (A), (B) and (C) are similar except for the flexible meth-oxy-meth-oxy group. The cyclo-hexane, cyclo-hexene and central cyclo-octane rings adopt chair, half-chair and chair-chair (extended crown) forms, respectively. The dioxolane rings are essentially planar, while the dioxolane ring of A' is slightly twisted from the mean plane. In the crystal of (A), inter-molecular O-H⋯O, C-H⋯O and C-H⋯π inter-actions link the independent benzoates alternately, forming a chain structure. In the crystals of (B) and (C), mol-ecules are linked through O-H⋯O and C-H⋯π inter-actions, and C-H⋯O hydrogen bonds, respectively, into similar chains. Further, weak inter-molecular C-H⋯O inter-actions connect the chains into a three-dimensional network in (A) and a sheet in (B), whereas no other interactions are observed for (C).

Crystal structure of (±)-(4RS,5RS,7SR)-4-[(1RS,2RS,3RS,6RS)-3-benzoyloxy-2-(2-hydroxyethyl)-6-methoxymethoxy-2-methylcyclohexyl]-8,10,10-trimethyl-2-oxo-1,3-dioxaspiro[4.5]dec-8-en-7-yl benzoate benzene monosolvate

In the title compound, C36H44O10·C6H6, the dioxolane ring adopts an envelope conformation with the C atom bonded to the H atom as the flap, while the cyclo-hexene and cyclo-hexane rings are in half-chair and chair conformations, respectively. In the crystal, a pair of O-H⋯O hydrogen bonds with an R 2 (2)(26) graph-set motif connect the benzoate mol-ecules into an inversion dimer. The dimers are linked by a weak C-H⋯O inter-action into a tape structure along [01-1]. The benzene mol-ecule links the tapes through C-H⋯O and C-H⋯π inter-actions, forming a sheet parallel to (100).

Characterization of an inclusion complex of ethyl benzoate with hydroxypropyl-β-cyclodextrin

The inclusion complex of ethyl benzoate with hydroxypropyl-β-cyclodextrin (HPCD) was prepared by a freeze-drying method and its characterizations were investigated by different analytical techniques including UV, FT-IR and phase solubility methods. All these approaches indicated that ethyl benzoate was able to form an inclusion complex with HPCD, and the ethyl benzoate/HPCD inclusion compounds exhibited different spectroscopic features and properties from ethyl benzoate. The stoichiometry of the complex was 1:1 and it was the benzene ring part of the ethyl benzoate molecule included into the HPCD cavities from the wider edge. The calculated apparent stability constant of the complex was 9485M−1. Moreover, the water solubility of ethyl benzoate was significantly improved by phase solubility studies. The release of ethyl benzoate was also regulated by the form of the inclusion complex. The results showed that HPCD was a proper excipient for increasing the solubility and controlled release of ethyl benzoate.