What question did this study set out to answer?

The study aims to explore and characterize the solid-state forms of tecovirimat, particularly its hydrates.

March 7, 2026

Preparation and powder X-ray diffraction study of tecovirimat hydrate solid forms

Key Points

The study aims to explore and characterize the solid-state forms of tecovirimat, particularly its hydrates.
Experimental conditions for crystallization of tecovirimat forms were identified.
Powder X-ray diffraction patterns were analyzed for phase purity using Rietveld refinement.
Single-crystal structures of two monohydrates and one hemihydrate were determined.
Three hydrated forms of tecovirimat were successfully crystallized: two monohydrates and one hemihydrate.
Single-crystal structures of monohydrate I and hemihydrate V were determined for the first time.
Monohydrate III's structure was redetermined for comparison under consistent conditions.

Abstract

Tecovirimat ST-246; systematic name: N-(3,5-dioxo-4-azatetracyclo[5.3.2.02,6.08,10dodec-11-en-4-yl)-4-(trifluoromethyl)benzamide monohydrate, C19H15F3N2O3] is an essential antiviral drug used against orthopoxviruses, yet its solid-state landscape remains only partially characterized. Here we identify experimental conditions enabling the reproducible crystallization of three hydrated forms reported in the patent literature: two monohydrates (I and III) and one hemihydrate (V). The phase purity of all samples was confirmed by Rietveld refinement of the powder X-ray diffraction patterns. The single-crystal structures of forms I and V were determined for the first time, whereas the structure of monohydrate III was redetermined at 293 K to allow direct comparison under identical conditions.

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Cite This Study

Ivlev et al. (Mon,) studied this question.

synapsesocial.com/papers/69abc1645af8044f7a4ea08a https://doi.org/https://doi.org/10.1107/s2053229626001154

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