scholarly journals Solubility Enhancement of Atrazine by Complexation with Cyclosophoraose Isolated from Rhizobium leguminosarum biovar trifolii TA-1

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 474 ◽  
Author(s):  
Yohan Kim ◽  
Vijay Shinde ◽  
Daham Jeong ◽  
Youngjin Choi ◽  
Seunho Jung
Keyword(s):  
Aqueous Solutions ◽  
Rhizobium Leguminosarum ◽  
Aqueous Solubility ◽  
Scanning Calorimetry ◽  
1H Nuclear Magnetic Resonance ◽  
Long Time ◽  
Ft Ir ◽  
Molecular Modeling Studies ◽  
Nuclear Overhauser ◽  
Rhizobium Leguminosarum Biovar Trifolii

Rhizobium leguminosarum biovar trifolii TA-1, a kind of soil bacteria, produces cyclosophoraoses (Cys). Cyclosophoraoses contain various ring sizes with degrees of polymerization ranging from 17 to 23. Atrazine is a hardly-soluble herbicide that contaminates soil and drinking water, and remains in soil for a long time. To remove this insoluble contaminant from aqueous solutions, we have enhanced the solubility of atrazine by complexation with Cys. The complex formation of Cys and atrazine was confirmed using 1H nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), field emission scanning electron microscopy (FE-SEM), rotating frame nuclear overhauser spectroscopy (ROESY), and molecular modeling studies. The aqueous solubility of atrazine was enhanced 3.69-fold according to the added concentrations (20 mM) of Cys, compared to the 1.78-fold enhancements by β-cyclodextrin (β-CD). Cyclosophoraoses as an excellent solubility enhancer with long glucose chains that can effectively capture insoluble materials showed a potential application of microbial polysaccharides in the removal of hazardous hardly-soluble materials from aqueous solutions in the fields of biological and environmental industry.

Preparation and physicochemical characterization of inclusion complexes derived from phytosterols and β-cyclodextrin

2019 ◽  
Vol 16 (2) ◽  
pp. 145-159 ◽  
Author(s):  
Ana Lía Rossi ◽  
Eduardo Miguel Rustoy ◽  
Gabriel Cases ◽  
Adriana Mabel Rosso
Keyword(s):  
Inclusion Complexes ◽  
High Resolution Mass Spectrometry ◽  
Nuclear Overhauser Effect ◽  
Structural Characteristics ◽  
Physicochemical Characterization ◽  
Aqueous Solubility ◽  
Scanning Calorimetry ◽  
Guest Molecules ◽  
Overhauser Effect ◽  
Nuclear Overhauser

Phytosterols (PS), that is vegetable sterols, are compounds widely recognized for lowering the absorption of cholesterol and decreasing cancer risk, with βsitosterol, stigmasterol and campesterol being the most abundant. As PS is poorly soluble in aqueous solutions, many approaches have been proposed to increase their solubility and bioavailability. β-cyclodextrin (β-CD) could be used to increase PS aqueous solubility because of its capacity to entrap a variety of hydrophobic guest molecules in its cavity. In this work, the formation of β-CD/PS inclusion complexes was confirmed by Differential Scanning Calorimetry (DSC), Electrospray Ionization-High Resolution Mass Spectrometry (ESIHRMS) and Fourier Transform Infrared Spectroscopy (FT-IR), while structural characteristics were determined by one- and two-dimensional Nuclear Magnetic Resonance (NMR) techniques. Results confirmed 1:1 binding stoichiometry, which suggests the total inclusion of rings and chains of the different PS. The hypothesis of folding of the lateral chains into the cavity may be supported by the multiple correlations observed in the Nuclear Overhauser Effect Spectroscopy (NOESY) and rotatingframe Nuclear Overhauser Effect Spectroscopy (ROESY) spectra.

scholarly journals Nepafenac-Loaded Cyclodextrin/Polymer Nanoaggregates: A New Approach to Eye Drop Formulation

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 229 ◽  
Author(s):  
Blanca Lorenzo-Veiga ◽  
Hakon Sigurdsson ◽  
Thorsteinn Loftsson
Keyword(s):  
1H Nmr ◽  
Self Assembly ◽  
Topical Administration ◽  
Water Soluble ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Nmr Studies ◽  
Water Soluble Polymers ◽  
1H Nuclear Magnetic Resonance ◽  
Ft Ir

The topical administration route is commonly used for targeting therapeutics to the eye; however, improving the bioavailability of drugs applied directly to the eye remains a challenge. Different strategies have been studied to address this challenge. One of them is the use of aggregates that are formed easily by self-assembly of cyclodextrin (CD)/drug complexes in aqueous solution. The aim of this study was to design a new eye drop formulation based on aggregates formed between CD/drug complexes. For this purpose, the physicochemical properties of the aggregates associated with six CDs and selected water-soluble polymers were analysed. Complex formation was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance spectroscopy (1H-NMR). Results showed that HPβCD performed best in terms of solubilization, while γCD performed best in terms of enhancing nanoaggregate formation. Formation of inclusion complexes was confirmed by DSC, FT-IR and 1H-NMR studies. A mixture of 15% (w/v) γCD and 8% (w/v) HPβCD was selected for formulation studies. It was concluded that formulations with aggregate sizes less than 1 µm and viscosity around 10–19 centipoises can be easily prepared using a mixture of CDs. Formulations containing polymeric drug/CD nanoaggregates represent an interesting strategy for enhanced topical delivery of nepafenac.

scholarly journals Effect of inclusion of citric acid and Lutrol® F-68 on ziprasidone and β-cyclodextrin complexation: Characterization, solubility and dissolution studies

2020 ◽  
Vol 11 (4) ◽  
pp. 280-284
Author(s):  
Vaishali Yogesh Londhe ◽  
Sreevidya Ramesh Krishnan
Keyword(s):  
Citric Acid ◽  
Antipsychotic Agent ◽  
Aqueous Solubility ◽  
In Vitro Dissolution ◽  
Scanning Calorimetry ◽  
Solubility Study ◽  
Dissolution Studies ◽  
Enhanced Solubility ◽  
Ft Ir

Ziprasidone (ZPR) is an antipsychotic agent having less solubility. It is used for the treatment of schizophrenia. Complexation of hydrophobic drugs with cyclodextrins leads to enhanced solubility and dissolution. In this study, inclusion complexes were prepared by different methods, using ZPR, β-cyclodextrin (β-CD), and different auxiliary agents like hydrophilic polymer and hydroxy acid (1:1:0.5) to improve the aqueous solubility. The characterization of the ternary complexes was carried out using solubility study, Differential scanning calorimetry (DSC), Powder X-ray diffraction (PXRD), Fourier transformation infrared spectroscopy (FT-IR) and in vitro dissolution studies. DSC, XRD, and FT-IR studies showed interaction in drug, cyclodextrin, and auxiliary agents which are confirmed by enhancement of solubility and dissolution. Spray-dried dispersion showed less crystallinity and higher solubility as compared to the kneading method for both citric acid and Lutrol® F-68. Thus, the investigation concludes that the presence of the auxiliary agent has a synergistic action on complexation with cyclodextrin, which helps to modify the physicochemical properties of the drug.

Polymerization and Characterization of Functionalized Poly(L-Lactide)

2009 ◽  
Vol 620-622 ◽  
pp. 595-598
Author(s):  
Yu Shun Jin ◽  
Fei Xiao ◽  
Wen Li Guo
Keyword(s):  
Ring Opening ◽  
Weight Percent ◽  
Molar Ratio ◽  
Polymerization Temperature ◽  
Scanning Calorimetry ◽  
1H Nuclear Magnetic Resonance ◽  
End Groups ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Functional poly(L-lactide) (PLLA-OH) containing vinyl groups as well as hydroxyl end groups was synthesized by ring-opening polymerization (ROP), using stannous octanoate as the catalyst and 2-hydroxyethyl methacrylate (HEMA) as the initiator. The structure of the obtained PLLA-OH was characterized using both Fourier Transform Infrared (FT-IR) spectroscopy and 1H nuclear magnetic resonance (1H-NMR) spectroscopy, while their crystallinities and thermo behavior were studied by differential scanning calorimetry (DSC), separately. The best condition for the ROP of the studied PLLA-OH was found with the polymerization temperature of T= 145 °C, the weight percent of the catalyst of 0.03 wt%, the ROP duration of 48 h and the L-lactide/initiator molar ratio of 100/1.

scholarly journals Investigating the phase-solubility and compatibility study of anticancer drug complexed with β-cyclodextrin and HP–β-cyclodextrin

2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Preeti Dhurve ◽  
Atul Tripathi ◽  
Bina Gidwani ◽  
Amber Vyas
Keyword(s):  
Aqueous Solubility ◽  
Phase Solubility ◽  
Compatibility Study ◽  
Formulation Development ◽  
Scanning Calorimetry ◽  
Solubility Study ◽  
Kneading Method ◽  
Phase Solubility Study ◽  
Critical Problems ◽  
Ft Ir

Poor  aqueous  solubility  and  dissolution  rates  are  critical  problems  that  hinders  the  formulation, development  and  delivery  of  most  of  BCS  class  II  and  class  IV  drugs.  Gefitinib  is  a  cytotoxic chemotherapeutic  drug  used  in  treatment  of  cancer.    The  objective  of  the  present  study  was  to investigate  the  drug-cyclodextrin  compatibility  study  by  FTIR  and  DSC  study.  The  phase solubility  study  revealed  formation  of  1:1  stoichiometry  binary  inclusion  complex.  The  complex was  prepared  by  kneading  method.  FT-IR  spectra  provided  the  data  indicating  that  the  HP-β-CD was  more  effective  than  β-CD.  Differential  scanning  calorimetry  thermograms  indicated  stronger amorphization and entrapment of  gefitinib with HP-β-CD.

scholarly journals Native Cyclodextrins as Complexation Agents for Pterostilbene: Complex Preparation and Characterization in Solution and in the Solid State

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 8
Author(s):  
Laura Catenacci ◽  
Alexios I. Vicatos ◽  
Milena Sorrenti ◽  
Maria Cristina Bonferoni ◽  
Mino R. Caira
Keyword(s):  
Solid State ◽  
Complex Formation ◽  
Aqueous Solubility ◽  
Molar Ratio ◽  
Phase Solubility ◽  
Scanning Calorimetry ◽  
Complex Preparation ◽  
Ft Ir ◽  
Sugar Levels ◽  
Co Precipitation

Pterostilbene (3,5-dimethoxy-4′-hydroxystilbene, PTB) is a natural dietary stilbene, occurring primarily in blueberries and Pterocarpus marsupium heartwood. The interest in this compound is related to its different biological and pharmacological properties, such as its antioxidant, anti-inflammatory, and anticarcinogenic activities and its capacity to reduce and regulate cholesterol and blood sugar levels. Nevertheless, its use in therapy is hindered by its low aqueous solubility; to overcome this limitation we studied the feasibility of the use of cyclodextrins (CDs) as solubility-enhancing agents. CDs are natural macrocyclic oligomers composed of α-d-glucose units linked by α-1,4 glycosidic bonds to form torus-shaped molecules, responsible for inclusion complex formation with organic molecules. In particular, the aim of this study was to evaluate the feasibility of complexation between PTB and native CDs using various preparative methods. The isolated solid products were characterized using differential scanning calorimetry (DSC), simultaneous thermogravimetric/DSC analysis (TGA/DSC), Fourier transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) on powder and single crystals. The results indicated little or no evidence of the affinity of PTB to complex with α-CD using the kneading method. However, with β-CD and γ-CD thermal analysis revealed an interaction which was also corroborated by FT-IR and 1H-NMR spectroscopy. With β-CD, a hydrated complex of PTB was isolated and its characterization by single-crystal XRD revealed, for the first time, the mode of inclusion of the PTB molecule in the cavity of a CD. To complement the solid-state data, liquid-phase studies were carried out to establish the effect of CDs on the aqueous solubility of PTB and to determine the complex stoichiometries and the association constants for complex formation. Phase-solubility studies showed AL-type profiles for α- and β-CD and a BS profile for γ-CD, with K1:1 values of 1144, 4950, and 133 M−1 for α-CD·PTB, β-CD·PTB, and γ-CD·PTB, respectively. The stoichiometry of CD·PTB complexes, determined by Job’s method, revealed for each system a 1:1 molar ratio. The dissolution rate of PTB was approximately doubled just by employing simple physical mixtures, but the best performance was achieved by products obtained via kneading and co-precipitation, which effected the complete dissolution of PTB in 40 and 20 min for β-CD and γ-CD, respectively.

Fenofibrate Solid Dispersion for Improving Oral Bioavailability: Preparation, and Characterization and in vivo Evaluation

2020 ◽  
Vol 13 (5) ◽  
pp. 5102-5109
Author(s):  
Venu Madhav K ◽  
Somnath De ◽  
Chandra Shekar Bonagiri ◽  
Sridhar Babu Gummadi
Keyword(s):  
Oral Bioavailability ◽  
Oral Delivery ◽  
Solid Dispersions ◽  
In Vitro Release ◽  
Aqueous Solubility ◽  
Water Soluble ◽  
Scanning Calorimetry ◽  
In Vivo Evaluation

Fenofibrate (FN) is used in the treatment of hypercholesterolemia. It shows poor dissolution and poor oral bioavailability after oral administration due to high liphophilicity and low aqueous solubility. Hence, solid dispersions (SDs) of FN (FN-SDs) were develop that might enhance the dissolution and subsequently oral bioavailability. FN-SDs were prepared by solvent casting method using different carriers (PEG 4000, PEG 6000, β cyclodextrin and HP β cyclodextrin) in different proportions (0.25%, 0.5%, 0.75% and 1% w/v). FN-SDs were evaluated solubility, assay and in vitro release studies for the optimization of SD formulation. Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) analysis was performed for crystalline and morphology analysis, respectively. Further, optimized FN-SD formulation evaluated for pharmacokinetic performance in Wistar rats, in vivo in comparison with FN suspension.  From the results, FN-SD3 and FN-SD6 have showed 102.9 ±1.3% and 105.5±3.1% drug release, respectively in 2 h. DSC and PXRD studies revealed that conversion of crystalline to amorphous nature of FN from FT-SD formulation. SEM studies revealed the change in the orientation of FN when incorporated in SDs. The oral bioavailability FN-SD3 and FN-SD6 formulations exhibited 2.5-folds and 3.1-folds improvement when compared to FN suspension as control. Overall, SD of FN could be considered as an alternative dosage form for the enhancement of oral delivery of poorly water-soluble FN.

Enhancement of Solubility and Dissolution Rate of Poorly Water Soluble Drug using Cosolvency and Solid Dispersion Techniques

1970 ◽  
Vol 1 (4) ◽  
pp. 349-356
Author(s):  
Meka Lingam ◽  
Vobalaboina Venkateswarlu
Keyword(s):  
Dissolution Rate ◽  
Solid Dispersions ◽  
Physicochemical Characterization ◽  
Aqueous Solubility ◽  
Water Soluble ◽  
Scanning Calorimetry ◽  
Peg 400 ◽  
Water Soluble Drug ◽  
Poorly Water Soluble ◽  
Poorly Water Soluble Drug

The low aqueous solubility of celecoxib (CB) and thus its low bioavailability is a problem.    Thus, it is suggested to improve the solubility using cosolvency and solid dispersions techniques. Pure CB has solubility of 6.26±0.23µg/ml in water but increased solubility of CB was observed with increasing concentration of cosolvents like PEG 400, ethanol and propylene glycol. Highest solubility (791.06±15.57mg/ml) was observed with cosolvency technique containing the mixture of composition 10:80:10%v/v of water: PEG 400: ethanol. SDs with different polymers like PVP, PEG were prepared and subjected to physicochemical characterization using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), solubility and dissolution studies. These studies reveals that CB exists mainly in amorphous form in prepared solid dispersions of PVP, PEG4000 and PEG6000 further it can also be confirmed by solubility and dissolution rate studies. Solid dispersions of PV5 and PV9 have shown highest saturation solubility and dissolution rate

Thermal Behaviour of Candesartan Active substance and in pharmaceutical compounds

2017 ◽  
Vol 68 (8) ◽  
pp. 1895-1902
Author(s):  
Ioana Cristina Tita ◽  
Eleonora Marian ◽  
Bogdan Tita ◽  
Claudia Crina Toma ◽  
Laura Vicas
Keyword(s):  
Thermal Behaviour ◽  
Active Substance ◽  
Pharmaceutical Research ◽  
Pharmaceutical Product ◽  
Nitrogen Atmosphere ◽  
Pure Substance ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ft Ir

Thermal analysis is one of the most frequently used instrumental techniques in the pharmaceutical research, for the thermal characterization of different materials from solids to semi-solids, which are of pharmaceutical relevance. In this paper, simultaneous thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) were used for characterization of the thermal behaviour of candesartan cilexetil � active substance (C-AS) under dynamic nitrogen atmosphere and nonisothermal conditions, in comparison with pharmaceutical product containing the corresponding active substance. It was observed that the commercial samples showed a different thermal profile than the standard sample, caused by the presence of excipients in the pharmaceutical product and to possible interaction of these with the active substance. The Fourier transformed infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRPD) were used as complementary techniques adequately implement and assist in interpretation of the thermal results. The main conclusion of this comparative study was that the TG/DTG and DSC curves, together with the FT-IR spectra, respectively X-ray difractograms constitute believe data for the discrimination between the pure substance and pharmaceutical forms.

The Development of Pemetrexed Diacid-Loaded Gelatin-Cloisite 30B (MMT) Nanocomposite for Improved Oral Efficacy Against Cancer: Characterization, In-Vitro and Ex-Vivo Assessment

2020 ◽  
Vol 17 (3) ◽  
pp. 246-256
Author(s):  
Kriti Soni ◽  
Ali Mujtaba ◽  
Md. Habban Akhter ◽  
Kanchan Kohli
Keyword(s):  
Drug Release ◽  
Oral Delivery ◽  
Ex Vivo ◽  
Confocal Laser ◽  
Release Mechanism ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Cloisite 30B ◽  
Ft Ir

Aim: The intention of this investigation was to develop Pemetrexed Diacid (PTX)-loaded gelatine-cloisite 30B (MMT) nanocomposite for the potential oral delivery of PTX and the in vitro, and ex vivo assessment. Background: Gelatin/Cloisite 30 B (MMT) nanocomposites were prepared by blending gelatin with MMT in aqueous solution. Methods: PTX was incorporated into the nanocomposite preparation. The nanocomposites were investigated by Fourier Transmission Infra Red Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM) X-Ray Diffraction (XRD) and Confocal Laser Microscopy (CLSM). FT-IR of nanocomposite showed the disappearance of all major peaks which corroborated the formation of nanocomposites. The nanocomposites were found to have a particle size of 121.9 ± 1.85 nm and zeta potential -12.1 ± 0.63 mV. DSC thermogram of drug loaded nanocomposites indicated peak at 117.165 oC and 205.816 oC, which clearly revealed that the drug has been incorporated into the nanocomposite because of cross-linking of cloisite 30 B and gelatin in the presence of glutaraldehyde. Results: SEM images of gelatin show a network like structure which disappears in the nanocomposite. The kinetics of the drug release was studied in order to ascertain the type of release mechanism. The drug release from nanocomposites was in a controlled manner, followed by first-order kinetics and the drug release mechanism was found to be of Fickian type. Conclusion: Ex vivo gut permeation studies revealed 4 times enhancement in the permeation of drug present in the nanocomposite as compared to plain drug solution and were further affirmed by CLSM. Thus, gelatin/(MMT) nanocomposite could be promising for the oral delivery of PTX in cancer therapy and future prospects for the industrial pharmacy.

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