Chemical Engineering and Industrial Chemistry

Formation of Pharmaceutical Salts and Cocrystals via Vapour-Assisted Tumbling (VAT) – A Solvent Efficient Process with Potential Industrial Applications



Crystallisations on both the academic and industrial scale often use large volumes of solvent. In order decrease the environmental impact of such processes, new techniques must be discovered that increase the efficiency of the solvents used. Introduced here is a process that combines repurposed industry standard hardware and aspects of mechanochemistry to produce a technique we call “Vapour Assisted Tumbling” (VAT). Pharmaceutical and well-known cocrystals and salts were formed by tumbling the coformers in an atmosphere of vaporised solvent, in this study, methanol (MeOH). This was done inside a custom built analogue of an industrial rotary cone dryer (RCD). It was found that a desired solid form could be obtained as monitored by powder X-ray diffraction and differential scanning calorimetry. By repurposing industrial RCDs, it is feasible that solid forms can be crystallised with both minimal and reusable/recyclable solvent – drastically lowering the environmental impact of such transformations.

Version notes

Updated to more descriptive title. Included a new citation. Corrected SI description mistake (TGA to DSC). Now with the correct non-formatted pdf!


Thumbnail image of VAT - AJStirk - ChemRxiv v2-1.pdf

Supplementary material

Thumbnail image of VAT - AJStirk - SI ChemRxiv v2.pdf
VAT - Supporting Information
Supporting information for the VAT process. Includes PXRD, DSC and IR data.