scholarly journals Stabilization of Metastable Indomethacin α in Cellulose Nanocrystal Aerogel Scaffolds

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 441
Author(s):  
Manali Banerjee ◽  
Blair Brettmann
Keyword(s):  
Differential Scanning Calorimetry ◽  
Active Pharmaceutical Ingredient ◽  
Cellulose Nanocrystal ◽  
Stable Form ◽  
Scanning Calorimetry ◽  
Seed Crystals ◽  
Polymorphic Forms ◽  
Model Drug ◽  
External Stimuli ◽  
Metastable Forms

Indomethacin (IM) is a small molecule active pharmaceutical ingredient (API) that exhibits polymorphism with the γ-form being the most thermodynamically stable form of the drug. The α-form is metastable, but it exhibits higher solubility, making it a more attractive form for drug delivery. As with other metastable polymorphs, α-IM undergoes interconversion to the stable form when subjected to certain stimuli, such as solvent, heat, pH, or exposure to seed crystals of the stable form. In this study, IM was crystallized into cellulose nanocrystal aerogel scaffolds as a mixture of the two polymorphic forms, α-IM and γ-IM. Differential scanning calorimetry (DSC) and Raman spectroscopy were used to quantitatively determine the amount of each form. Our investigation found that the metastable α-IM could be stabilized within the aerogel without phase transformation, even in the presence of external stimuli, including heat and γ-IM seed crystals. Because interconversion is often a concern during production of metastable forms of APIs, this approach has important implications in being able to produce and stabilize metastable drug forms. While IM was used as a model drug in this study, this approach could be expanded to additional drugs and provide access to other metastable API forms.

Applying Differential Scanning Calorimetry to Detergency Studies of Oily Soil

1992 ◽  
Vol 62 (2) ◽  
pp. 101-104 ◽  
Author(s):  
Mamiko Yatagai ◽  
Motoko Komaki ◽  
Toshimasa Hashimoto
Keyword(s):  
Differential Scanning Calorimetry ◽  
Filter Paper ◽  
Soil Removal ◽  
Fibrous Materials ◽  
Oily Soil ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
Peak Areas ◽  
Polymorphic Forms

Differential scanning calorimetry (DSC) has been applied to studies of oily soil removal from fibrous materials. Fabric and filter paper were soiled with various oily substances present in sebum. After washing, the fibrous samples were subjected to DSC measurements. The residual oily soils on the samples were analyzed by the melting peak areas of the DSC heating curves, a method that is widely applicable to various oily substances with different melting points and polymorphic forms. Various woven or nonwoven fibrous samples can be scanned, regardless of sample size in washing experiments.

Thermotropic phase properties and structure of 1, 2-distearoylgalactosylglycerols in aqueous systems

1983 ◽  
Vol 388 (1794) ◽  
pp. 247-247 ◽  
Keyword(s):  
Liquid Crystalline ◽  
Lipid A ◽  
Stable Form ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Metastable Form ◽  
History Of ◽  
The Difference ◽  
Stable Forms ◽  
Metastable Forms

Differential scanning calorimetry and X-ray diffraction measurements indicate that aqueous dispersions of the 1, 2-distearoyl derivatives of monogalactosyl and digalactosyldiacylglycerol exhibit complex poly­morphic behaviour involving the formation of stable and metastable structural forms. The relative proportions of these forms are dependent on the thermal history of the samples. Two distinct gel phases can be identified for the monogalactosyl lipid; a stable highly ordered form (MGDG I ) and a metastable form (MGDG II ). There is also some indication of a low temperature modification of the stable form (MGDG´ I ). Analogous stable and metastable forms of the digalactosyl lipid (DGDG I and DGDG II ) can also be identified. In both cases, the metastable form appears on initial crystallization from the liquid-crystalline state and the stable form appears only after prolonged equilibration at room temperature or after annealing the samples at higher temperatures. In the case of the monogalactosyl lipid, thermal equilibration leads to a complete, or nearly complete, conversion to the stable form. The equilibrium state in the digalactosyl lipid, however, lies much closer to the metastable form. Calorimetric measurements performed on samples containing limited water and thermogravimetric measurements indicate that the difference between the metastable and stable forms lies in their extents of hydration, and that the conversion of the metastable to the stable form involves a dehydration of the lipid. Comparison with other lipids showing similar polymorphic behaviour suggests that this process may be a common feature of lipids that tend to bind little water and of lipid systems in which extensive divalent ion bridging between neighbouring lipid headgroups can occur.

scholarly journals Kinetic Studies of Transition of Seratrodast Polymorphic Forms by Differential Scanning Calorimetry

1995 ◽  
Vol 115 (11) ◽  
pp. 937-943 ◽  
Author(s):  
Yukihiro IKEDA ◽  
Koji NISHIJIMA ◽  
Noriaki TOKAI ◽  
Kiyoshi NISHI
Keyword(s):  
Differential Scanning Calorimetry ◽  
Kinetic Studies ◽  
Scanning Calorimetry ◽  
Polymorphic Forms

scholarly journals Quantifying Solid-State Mixtures of Crystalline Indomethacin by Raman Spectroscopy Comparison with Thermal Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Eman Atef ◽  
Harsh Chauhan ◽  
Dev Prasad ◽  
Dunesh Kumari ◽  
Charles Pidgeon
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Solid State ◽  
Binary Mixtures ◽  
Quantitative Method ◽  
Reliable Method ◽  
Polymorphic Form ◽  
Scanning Calorimetry ◽  
Polymorphic Forms

This paper investigates Raman spectroscopy as a quick and reliable method to quantify the alpha (α) and gamma (γ) polymorphic forms of indomethacin compared to differential scanning calorimetry (DSC). Binary mixtures with different ratios of α and γ indomethacin were prepared and analyzed by Raman and DSC. The Raman method was found to be more reliable and superior compared to DSC. The partial conversion of the alpha to gamma polymorphic form during the DSC measurement was the major limitation for the use of full DSC as a quantitative method and resulted in difference between the calculated and measured enthalpy of both polymorphic forms.

scholarly journals DEVELOPMENT OF NOVEL MICROSTRUCTURED LIPID CARRIERS FOR DISSOLUTION RATE ENHANCEMENT OF ALBENDAZOLE

2020 ◽  
pp. 173-178
Author(s):  
CASTRO ALPIZAR J. A. ◽  
PACHECO MOLINA J. ◽  
VARGAS MONGE R. ◽  
MADRIGAL REDONDO G.
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dissolution Rate ◽  
Active Pharmaceutical Ingredient ◽  
Diffusion Method ◽  
Dissolution Testing ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Dissolution Rate Enhancement ◽  
Rate Of Dissolution ◽  
Low Solubility

Objective: This study aimed to develop a microstructured lipid carrier that improves the rate of dissolution of the active pharmaceutical ingredient (API) Albendazole. Methods: A solvent diffusion method was used for the development of microstructured lipid carriers. The developed carriers were characterized by optical microscopy, infrared spectroscopy, differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and dissolution testing. Results: The morphology of the carriers was irregular, and their size tends to decrease with the addition of modifiers. Furthermore, the diffractograms and the thermograms indicated a loss of crystallinity. The thermograms and infrared spectra showed that there are not chemical incompatibilities between the API and the excipients. When the lipid carrier particles were modified with Aerosil® 200 (specifically when using this excipient at a level of 6% w/w), dissolution was increased up to 85.96±1.17 % of the drug content as per USP test for Albendazole tablets in comparison with 36.13±0.52 % for a lipid carrier formulation without modifiers. Conclusion: It was demonstrated that it is possible to develop a modified lipid carrier that improves the dissolution rate of an API with a low solubility, which was related to the amorphization of the API crystalline structure.

Thermotropic phase properties and structure of 1,2-distearoylgalactosylglycerols in aqueous systems

1983 ◽  
Vol 218 (1212) ◽  
pp. 349-364 ◽  
Keyword(s):  
Liquid Crystalline ◽  
Lipid A ◽  
Stable Form ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Metastable Form ◽  
History Of ◽  
The Difference ◽  
Stable Forms ◽  
Metastable Forms

Differential scanning calorimetry and X-ray diffraction measurements indicate that aqueous dispersions of the 1,2-distearoyl derivatives of monogalactosyl and digalactosyldiacylglycerol exhibit complex polymorphic behaviour involving the formation of stable and metastable structural forms. The relative proportions of these forms are dependent on the thermal history of the samples. Two distinct gel phases can be identified for the monogalactosyl lipid; a stable highly ordered form (MGDG I ) and a metastable form (MGDG II ). There is also some indication of a low temperature modification of the stable form (MGDG´ I ). Analogous stable and metastable forms of the digalactosyl lipid (DGDG I and DGDG II ) can also be identified. In both cases, the metastable form appears on initial crystallization from the liquid-crystalline state and the stable form appears only after prolonged equilibration at room tempera­ture or after annealing the samples at higher temperatures. In the case of the monogalactosyl lipid, thermal equilibration leads to a complete, or nearly complete, conversion to the stable form. The equilibrium state in the digalactosyl lipid, however, lies much closer to the metastable form. Calorimetric measurements performed on samples containing limited water and thermogravimetric measurements indicate that the difference between the metastable and stable forms lies in their extents of hydration, and that the conversion of the metastable to the stable form involves a dehydration of the lipid. Comparison with other lipids showing similar polymorphic behaviour suggests that this process may be a common feature of lipids that tend to bind little water and of lipid systems in which extensive divalent ion bridging between neighbouring lipid headgroups can occur.

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