Escitalopram oxalate: co-existence of oxalate dianions and oxalic acid molecules in the same crystal

Harrison, William T. A.; Yathirajan, H. S.; Bindya, S.; Anilkumar, H. G.; Devaraju,

doi:10.1107/s010827010605520x

Cited by 46 publications

(50 citation statements)

References 7 publications

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“…The results were comparable for all crystals examined. The lattice parameters (Table 1) are closely comparable to those reported for the S ‐enantiomer ( P 2 1 , a =7.9355(3), b = 24.7376(9), c = 11.1332(5) Å, β = 106.859(2)° at 120 K),10 and the structure is essentially that expected by analogy with that of the pure enantiomer. The centre of inversion in the oxalate dianion is crystallographic, so that there is only one protonated citalopram molecule in the asymmetric unit in space group P 2 1 / a (the nonstandard setting is chosen for consistency with the cell setting reported for the enantiomer).…”

Section: Resultssupporting

confidence: 73%

“…The crystal structure of ( S )‐citalopram oxalate has been reported 10. In the crystalline state, the compound is formulated as 2C 20 H 22 FN 2 O + ·C 2 O 4 2− ·C 2 H 2 O 4 ·0.325H 2 O, containing oxalate dianions and neutral oxalic acid molecules.…”

Section: Introductionmentioning

confidence: 99%

“… Hydrogen‐bonded unit in the crystal structure of ( S )‐citalopram oxalate10 showing pseudo‐inversion symmetry. The two distinct molecular conformations referred to in the text are labelled A and B.…”

Section: Introductionmentioning

confidence: 99%

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Formation of solid solutions between racemic and enantiomeric citalopram oxalate

2011

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The X-ray powder diffractograms of racemic citalopram oxalate and (S)-citalopram oxalate are very similar, but the melting point of the racemate is higher than that of the pure enantiomer. The higher melting point indicates that the racemate is a racemic compound, rather than a conglomerate. The crystal structure of the enantiomer contains two molecules of (S)-citalopram in the asymmetric unit. The conformation of the two molecules is different but they approximate mirror images of each other if the aromatic groups are interchanged. The crystal structure of the racemate is essentially isostructural with that of the enantiomer, having almost the same cell parameters but containing a crystallographic inversion centre that is not retained in the enantiomer structure. The closely-comparable crystal structures permit solid solutions to be formed between racemic and enantiomeric citalopram oxalate. Phase diagrams of the (R)-citalopram and (S)-citalopram oxalate system are constructed, and they show that solid solutions are formed at all ratios of the two enantiomers.

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Section: Resultssupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

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Formation of solid solutions between racemic and enantiomeric citalopram oxalate

2011

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“…Previously, a cocrystal of the salt of the API with an unionized counterion was reported for the anticonvulsant drug valproic acid, wherein the API comprised cocrystalline form of sodium valproate salt with valproic acid 31. The use of cocrystals in a similar manner to salts in order to alter the physicochemical properties of API has been comprehensively investigated,32–38 although only one paper published so far reports on the coexistence of dianions and an unionized form of the acid in the same crystal lattice; similar to what we have determined for SA; it was a hydrated crystal of escitalopram oxalate with oxalic acid 39…”

Section: Resultsmentioning

confidence: 80%

Solid‐state characterization of novel active pharmaceutical ingredients: Cocrystal of a salbutamol hemiadipate salt with adipic acid (2:1:1) and salbutamol hemisuccinate salt

Paluch

Tajber

Elcoate

et al. 2011

Journal of Pharmaceutical Sciences

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“…They found that the position of the proton was temperature‐dependent, and under certain conditions it behaved as a partial salt (partial proton transfer) and in other cases as a cocrystal. Also, the crystal structure of escitalopram oxalate shows one oxalate dianion and one neutral oxalic acid molecule for every two escitalopram cations [62]. Hence, di‐escitalopram oxalate is cocrystallised with oxalic acid, and should be viewed both as a cocrystal as well as a salt.…”

Section: What's In the Name?mentioning

confidence: 99%

The solid-state continuum: a perspective on the interrelationships between different solid-state forms in drug substance and drug product

Elder

Patterson

Holm

2014

Journal of Pharmacy and Pharmacology

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Objective The objective of the review is to provide an overview of the nomenclature used in the solid-state continuum and relate these to the development of drug substances and drug products. Key findings The importance of a rational approach to solid-state form selection, including integrated decision making (ensuring equal weight is given to the needs of the drug substance and the drug product), is vital for the effective development of a drug candidate. For example, how do secondary processing considerations influence the selection of drug substance solid-state form and resulting formulation, and how can drug substance solid-state form be used to optimise secondary processing? Further, the potential use of 'crystal' engineering to optimise stability, purity and optical resolutions, and the linked regulatory requirements, will be discussed. Summary The nomenclature used in the solid-state continuum, which contains a large number of different crystalline and non-crystalline forms, for example, amorphous systems, was reviewed. Further, the significant role of the drug substance within the solid oral dose form from a physicochemical perspective was covered.

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Escitalopram oxalate: co-existence of oxalate dianions and oxalic acid molecules in the same crystal

Cited by 46 publications

References 7 publications

Formation of solid solutions between racemic and enantiomeric citalopram oxalate

Formation of solid solutions between racemic and enantiomeric citalopram oxalate

Solid‐state characterization of novel active pharmaceutical ingredients: Cocrystal of a salbutamol hemiadipate salt with adipic acid (2:1:1) and salbutamol hemisuccinate salt

The solid-state continuum: a perspective on the interrelationships between different solid-state forms in drug substance and drug product

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