| 1. |
- Ahuja, Dipali, et al.
(författare)
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Solution and calorimetric thermodynamic study of a new 1:1 sulfamethazine-3-methylsalicylic acid co-crystal
- 2020
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Ingår i: CrystEngComm. - : Royal Society of Chemistry (RSC). - 1466-8033. ; 22:20, s. 3463-3473
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Tidskriftsartikel (refereegranskat)abstract
- A new 1:1 co-crystal of sulfamethazine (API, SMT) and 3-methylsalicylic acid (coformer, 3mSA) has been synthesized and its crystal structure solved by single crystal X-ray diffraction (XRD). The co-crystal has been thoroughly characterized by powder XRD, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The pure co-crystal could be synthesized by solvent drop grinding, cooling crystallization and slurry conversion co-crystallization. Ternary phase diagrams have been constructed in methanol and acetonitrile at 30 degrees C. The co-crystal exhibits incongruent dissolution in both solvents. The thermodynamics of co-crystal formation have been estimated from solubility data and calorimetric data, respectively, showing that formation of the SMT-3mSA co-crystal from its solid components is spontaneous and entropy-driven. The co-crystal formation is associated with a 5% increase in molecular volume. A relationship between the size of the region where the co-crystal is the most stable solid phase and the relative solubility of the co-crystal components has been uncovered. The co-crystal region becomes smaller as the solubility ratio increases.
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| 2. |
- Diniz, Mariana O., et al.
(författare)
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New Solid Forms of Griseofulvin : A Solvate and a Relict Polymorph Related to Reported Solvates
- 2023
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 23:12, s. 8953-8961
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Tidskriftsartikel (refereegranskat)abstract
- This work presents two new solid forms, a polymorph and a solvate, of the antifungal active pharmaceutical ingredient griseofulvin (GSF). The novel forms were characterized by powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis, and their crystal structures were determined by single-crystal X-ray diffraction. The new polymorphic form (GSF Form VI) was obtained upon drying at room temperature the GSF-acetonitrile solvate. GSF Form VI is a relict structure related to reported solvates of GSF. Thermal stability studies show that Form VI is metastable and monotropically related to the stable GSF Form I. The new GSF-n-butyl acetate solvate was obtained by crystallization from an n-butyl acetate solution. The stoichiometry of the n-butyl acetate solvate is 1:0.5. The solvate loses the solvent from the crystal lattice at a temperature between 363.15 and 374.15 K.
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