Structural relationships, thermal properties, and physicochemical characterization of anhydrous and solvated crystalline forms of tetroxoprim

2002 ◽  
Vol 91 (2) ◽  
pp. 467-481 ◽  
Author(s):  
Mino R. Caira ◽  
Giampiero Bettinetti ◽  
Milena Sorrenti
Keyword(s):  
Thermal Properties ◽  
Physicochemical Characterization ◽  
Structural Relationships ◽  
Crystalline Forms

Physicochemical Characterization of Arrowroot Starch (Maranta arundinacea Linn) and Glycerol/Arrowroot Starch Membranes

2014 ◽  
Vol 10 (4) ◽  
pp. 727-735 ◽  
Author(s):  
Carlos Andrés Sandoval Gordillo ◽  
Germán Ayala Valencia ◽  
Rubén Antonio Vargas Zapata ◽  
Ana Cecilia Agudelo Henao
Keyword(s):  
Thermal Properties ◽  
Amylose Content ◽  
Starch Content ◽  
Physicochemical Characterization ◽  
Industrial Applications ◽  
Glycerol Content ◽  
Scanning Calorimetry ◽  
Size Dispersion ◽  
Arrowroot Starch

Abstract In the current work, physicochemical properties of arrowroot starch and thermal properties of glycerol/arrowroot starch membranes were investigated. Arrowroot starch exhibited high purity (starch content >99%) with amylose content >40% and granule size dispersion between 29 and 126 μm. Arrowroot starch has a gelatinization temperature of 63.94°C and a B-type crystalline structure. Arrowroot starch, in combination with three levels of glycerol, was used to manufacture membranes by casting method. Increasing the plasticizer effect due to glycerol content increased the water weight loss of the membranes at temperatures higher than 110°C. Additionally, the onset temperature of the endothermic peak observed by differential scanning calorimetry and associated to water removal from the membranes changed with glycerol content. Physicochemical and thermal properties of arrowroot starch and glycerol/arrowroot starch membranes were similar to those reported previously for other starch sources. From the data obtained in this study, it is clear that arrowroot starch could have promising industrial applications.

scholarly journals Assessment of analytical techniques for characterization of crystalline clopidogrel forms in patent applications

2014 ◽  
Vol 50 (2) ◽  
pp. 229-242
Author(s):  
Luiz Marcelo Lira ◽  
Alexandre Lopes Lourenço ◽  
Guilherme Ferreira Neves ◽  
Valéria Pereira de Sousa ◽  
Carlos Rangel Rodrigues ◽  
...  
Keyword(s):  
Patent Application ◽  
Physicochemical Characterization ◽  
Analytical Techniques ◽  
Clopidogrel Bisulfate ◽  
Chemical Crystallography ◽  
Crystallization Procedure ◽  
Patent Applications ◽  
Blockbuster Drug ◽  
Crystalline Forms

The aim of this study was to evaluate two important aspects of patent applications of crystalline forms of drugs: (i) the physicochemical characterization of the crystalline forms; and (ii) the procedure for preparing crystals of the blockbuster drug clopidogrel. To this end, searches were conducted using online patent databases. The results showed that: (i) the majority of patent applications for clopidogrel crystalline forms failed to comply with proposed Brazilian Patent Office guidelines. This was primarily due to insufficient number of analytical techniques evaluating the crystalline phase. In addition, some patent applications lacked assessment of chemical/crystallography purity; (ii) use of more than two analytical techniques is important; and (iii) the crystallization procedure for clopidogrel bisulfate form II were irreproducible based on the procedure given in the patent application.

Physicochemical Characterization of Diclofenac N-(2-Hydroxyethyl)pyrrolidine: Anhydrate and Dihydrate Crystalline Forms

1996 ◽  
Vol 85 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Mark T. Ledwidge ◽  
Sylvia M. Draper ◽  
Deborah J. Wilcock ◽  
Owen I. Corrigan
Keyword(s):  
Physicochemical Characterization ◽  
Crystalline Forms

scholarly journals Solid-State Characterization of Different Crystalline Forms of Sitagliptin

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2351 ◽  
Author(s):  
Nayana C. F. Stofella ◽  
Andressa Veiga ◽  
Laiane J. Oliveira ◽  
Elisa F. Montin ◽  
Itamar F. Andreazza ◽  
...  
Keyword(s):  
Solid State ◽  
Melting Point ◽  
Physicochemical Characterization ◽  
Spectroscopic Techniques ◽  
Scanning Calorimetry ◽  
Pharmaceutical Dosage Form ◽  
Base Form ◽  
Crystalline Forms ◽  
Solid State Characterization

Sitagliptin is an inhibitor of the enzyme dipeptidyl peptidase-4, used for the treatment of type 2 diabetes mellitus. The crystal structure of active pharmaceutical solids determines their physical and chemical properties. The polymorphism, solvates and hydrates can influence the free energy, thermodynamic parameters, solubility, solid-state stability, processability and dissolution rate, besides directly affecting the bioavailability. Thus, the physicochemical characterization of an active pharmaceutical ingredient is required to guarantee the rational development of new dosage forms. In this context, we describe herein the solid-state characterization of three crystalline forms of sitagliptin: sitagliptin phosphate monohydrate, sitagliptin phosphate anhydrous and sitagliptin base form. The investigation was carried out using differential scanning calorimetry (DSC), thermogravimetry (TG)/derivative thermogravimetry (DTG), spectroscopic techniques, X-ray powder diffraction (XRPD) and morphological analysis by scanning electron microscopy. The thermal analysis revealed that during the dehydration of sitagliptin phosphate monohydrate (Tpeak = 134.43 °C, ΔH = −1.15 J g−1) there is a characteristic crystalline transition event, which alters the physicochemical parameters of the drug, such as the melting point and solubility. The crystalline behavior of sitagliptin base form differs from that of sitagliptin phosphate monohydrate and sitagliptin phosphate anhydrous, mainly with regard to the lower temperature of the fusion event. The melting point (Tpeak) values obtained were 120.29 °C for sitagliptin base form, 206.37 °C for sitagliptin phosphate monohydrate and 214.92 °C for sitagliptin phosphate anhydrous. In relation to the thermal stability, sitagliptin phosphate monohydrate and sitagliptin phosphate anhydrous showed a slight difference; however, both are more thermostable than the base molecule. Therefore, through this study it was possible to establish the most suitable crystalline form of sitagliptin for the development of a safe, effective and appropriate pharmaceutical dosage form.

Experimental Approach of Measuring Thermal Properties for Ecological Materials Based on Additives Cork or Wool and Illite

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
Soumia Mounir ◽  
Abdelhamid Khabbazi ◽  
Youssef Maaloufa ◽  
Asmae Khaldoun ◽  
Yassine El Hamdouni
Keyword(s):  
Thermal Properties ◽  
Heat Flow ◽  
Experimental Studies ◽  
Physicochemical Characterization ◽  
Thermal Characterization ◽  
Theoretical Models ◽  
Hot Plate ◽  
Knowing That ◽  
State Regime

This work is a contribution to understand the thermal properties of Illite with ecological additives granular presented by cork or fiber by wool in order to use those composites in building construction, the composites are air dried. Knowing that the clay composites were studied before, a series of experimental studies confirmed by complete theoretical models were conducted using different methods such as the asymmetrical hot plate in transient, steady-state regime, and flash methods in order to determine the thermal properties of the composite clay with ecological additives. Also, an analysis of sensibility of thermal properties was studied. For this purpose, a thermal characterization using hot plate and flash methods confirmed by complete theoretical models was studied. Then an analysis of the physicochemical characterization of clay was done to determine its characteristics. Finally, a study of depth heat flow diffusion was conducted to see the effect of additives on penetrating exterior heat flow inside house.

Optimization and Physicochemical Characterization of Chitosan and Chitosan Nanoparticles Extracted from the Crayfish Procambarus clarkii Wastes

2019 ◽  
Vol 38 (2) ◽  
pp. 385 ◽  
Author(s):  
Marwa M. El-Naggar ◽  
Wael S. I. Abou-Elmagd ◽  
Ashraf Suloma ◽  
Hamza A. El-Shabaka ◽  
Magdy T. Khalil ◽  
...  
Keyword(s):  
Procambarus Clarkii ◽  
Chitosan Nanoparticles ◽  
Physicochemical Characterization

Physicochemical Characterization of Solid Dispersions of Cefdinir with PVP K-30 and PEG 4000

2010 ◽  
Vol 3 (2) ◽  
pp. 948-956
Author(s):  
Kumar P ◽  
S Kumar ◽  
A Kumar ◽  
M Chander
Keyword(s):  
Solid Dispersions ◽  
Physicochemical Characterization ◽  
Drug Carriers ◽  
Dissolution Properties ◽  
Rate Of Dissolution ◽  
Peg 4000 ◽  
Release Studies ◽  
Crystalline Nature ◽  
Physical Mixtures

The purpose of this study was to prepare and characterize solid dispersions of the antibacterial agent Cefdinir with PEG 4000 and PVP K-30 with a view to improve its dissolution properties. Investigations of the properties of the dispersions were performed using release studies, X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR). The results obtained showed that the rate of dissolution of Cefdinir was considerably improved when formulated in solid dispersions with PVP K-30 and PEG 4000 as compared with pure drug and physical mixtures. The results from XRD studies showed the transition of crystalline nature of drug to amorphous form, while FTIR studies demonstrated the absence of drug-carriers interaction.

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