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Physical properties...
Physical properties and crystallization of theophylline co-crystals
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- Zhang, Shuo, 1983- (författare)
- KTH,Teknisk strömningslära,Transport Phenomena
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- Rasmuson, Åke, Professor (preses)
- KTH,Teknisk strömningslära
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- Svensson, Per, Adjunct Professor (opponent)
- KTH,Oorganisk kemi
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- Behm, Mårten, Professor (opponent)
- KTH,Tillämpad elektrokemi
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(creator_code:org_t)
- ISBN 9789174156898
- Stockholm : KTH, 2010
- Engelska vi, 47 s.
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Serie: Trita-CHE-Report, 1654-1081 ; 2010:26
- Relaterad länk:
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https://kth.diva-por... (primary) (Raw object)
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- This work focuses on the physical properties and crystallization of theophyline co-crystals. Co-crystals of theophylline with oxalic acid, glutaric acid and maleic acid have been investigated. The DSC curves of these co-crystals show that their first endothermic peaks are all lower than the melting temperature of theophylline. The decomposition temperature of theophylline – oxalic acid co-crystal is at about 230 °C, determined by DSC together with TGA. After decomposition, the remaining theophylline melts at about 279 °C, which is higher than the known melting temperature of theophylline, suggesting a structure difference, ie. a new polymorph may have been formed. The formation of hydrogen bonds in theophylline – oxalic acid co-crystal was investigated by FTIR. Changes of FTIR peaks around 3120 cm-1 reflects the hydrogen bond of basic N of theophylline and hydroxyl H of oxalic acid. The solubility of theophylline – oxalic acid co-crystal and theophylline – glutaric acid co-crystal was determined in 4:1 chlroform – methanol and in pure chloroform respectively. At equilibrium with the solid theophylline – oxalic acid co-crystal, the theophylline concentration is only 60 % of the corresponding value for the pure solid theophylline. At equilibrium with the solid theophylline – glutaric acid co-crystal, the theophylline concentration is at least 5 times higher than the corresponding value for the pure solid theophylline. Two phases of theophylline were found during the solubility determination. In the chloroform – methanol mixture (4:1 in volume ratio) the solubility of the stable polymorph of theophylline is found to be about 14 % lower than that of the metastable phase. Various aspects of the phase diagram of theophylline – oxalic acid co-crystal was explored. Theophylline – oxalic acid co-crystal has been successfully prepared via primary nucleation from a stoichiometric solution mixture of the two components in chloroform – methanol mixture. By slurry conversion crystallization, the co-crystal can be prepared in several solvents, and yield and productivity can be significantly increased. Theophylline – glutaric acid can be successfully prepared via both co-grinding of the two components and slow evaporation with seeding.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Kemiteknik -- Kemiska processer (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Chemical Engineering -- Chemical Process Engineering (hsv//eng)
Nyckelord
- Theophylline
- oxalic acid
- glutaric acid
- maleic acid
- co-crystal
- decomposition temperature
- melting temperature
- solubility
- crystallization
- Molecular transport processes in chemical process engineering
- Molekylära transportprocesser i kemisk processteknik
Publikations- och innehållstyp
- vet (ämneskategori)
- lic (ämneskategori)
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