CSP Services

XtalPi provides game-changing polymorph prediction (also known as crystal structure predition)that is pertinent throughout the drug development process and applicable across the biopharmaceutical industry. First of its kind, the XtalPi solution attains unparalleled speed and accuracy that makes it the industry.


Development Process

Identify the best solid form candidate in the early stage will support decision-making on solid form development in the later stages, such as formulation and manufacturing, and contributes to increased probability of success.


Clinical Trial Success

Better understanding of the molecule packing in cocrystals enable rational design of free forms, hydrates, salts and cocrystals with better solubility and stability, crucial for successful clinical trials.


IP Security and Shelf Life

Understanding the complete landscape of stable and metastable forms minimizes the risk of patent challenges, maximizing the patent life and prolonging the drug’s market exclusivity period.

Part of the Cases


A molecule could have several isomers, which should be analyzed before global search. Our conformational analysis processes intelligently scan the flexible torsional angle grouping, looking for all the isomers. Thus the local minimum points and low energy conformational space can be fully covered.


Stage 1. Analysis

Client send mol or SMILES file to XtalPI; XtalPi provides the quote about price and time.

We train and test 'Force Field' parameters for every complex molecule; implemented two different global search algorithms for cross-validation; and give the 'Intermediate Ranking' result.

Stage 2.

Eagle Search

Client approve the quote and send the purchase order; we return the preliminary CSP results.<br />

Due to the very weak interactions between organic small molecules, the final ranking employs a very high precision density functional method with dispersion correction, which provides energy resolution in kJ/mol.

Stage 3.

Blue-Whale Search

Client share the experimental structure and information to XtalPi; we returns the final CSP results.

There also lots of chemical or physical properties that we can calculate or predict, for example 'solubility'. If you or your company are intersted, please contact us.

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Further Service

'Finite Temperature Correction' to the energy landscape is one of our related service for customs.



Analyze Your CSP Report.

A smart tool for delivering ‘Crystal Structure Prediction Report’.

Do‘ with the data simply.


Content of A Report

A summary of the report and molecular.

This report presents final results for crystal structure prediction of the Axitinib default forms.

Our findings are shown in three sections: a summary of the molecular information and conformational analysis, the crystal structure predictions, and the employed methodology.

In the methodology section, we present the theory used in prediction. Besides the three result sections, there is another section listing XTALPI members involved in the project and the change log of different versions of reports.





Present the crystal conformation distribution.

The conformers of the API show in this section.

Conformation analysis was carried out with QM method along the rotatable bonds for Axitinib default force field training.

In crystal structure prediction, the flexible torsional angles are also varied together with the other variables (lattice parameters, molecule positions, molecule orientations etc.) to find the stable crystal forms.





Display all structures in the energy window.

The section’s figure presents the energy landscape ofAxitinib in both Z’=1 and Z’=2 forms.

5 crystal structures, 5 with Z’=1, were predicted in the most stable energy window, i.e. with a relative lattice energy within 5 kJ/mol of the lowest energy structure.

To see the details of a target structure, one can single click the point in the figure and more information will display on the right of the figure, including the crystal structure, the relative lattice energy, density, space group number, cell parameters and PXRD pattern. The structure is shown in a 3D view. One can zoom and rotate the structure with the mouse wheel and left mouse button, respectively.




Assigned structures with similar packing arrangement.

There are five published experimental crystal structures of anhydrate of axitinib.

Our predicted structures are compared with experimental information, either single crystal structures or PXRD patterns. The experimental similar structures found in our prediction are labeled with the unfilled diamond. If the experimental single crystal structure available, one can click the corresponding diamond to show the structural overlay (with their structural RMS). If only experimental PXRD patterns are available, only the patterns from predicted similar structures are compared with the experimental ones.





Cluster the inter-molecular hydrogen bonds.

This section shows ‘Hydrogen Bond’ groups of Axitinib.

The inter-molecular hydrogen bonding interaction makes an important contribution to the stabilization of crystal structures. Hydrogen bonds are defined as having distance(A…H) < 2.75 Angstrom and angle (A…H-D) > 120 degrees, where A, D and H represent the acceptor atom, donor antecedent atom, and donor hydrogen atom, respectively. After a visual check, we clustered the inter-molecular hydrogen bonds into 2 distinct groups (listed in the table) according to the spatial interaction patterns between the acceptor and donor atoms. One can click in the table to highlight a group of interest in the lattice energy landscape figure. Also, one can zoom in/out the 3D graph to see the detailed interaction pattern of each hydrogen bond group.




Finite temperature correction to the lattice landscape.

This section shows Free Energy data of Axitinb.

1. The finite temperature correction to the lattice landscape was performed for selected forms from CSP or experiment. These forms are ranked at () according to DFT lattice energies at 0 K (see the section “Energy Landscape” for details).

2. In the figure “Free Energy Change Relative to Form xx”, the relative free energy of different forms represents the relative stability of the given forms, i.e. lower free energy with better stability.

*Using the legend on the side of the graph one can “click” and “unclick” lines that are to remain visible in the graph.
*With the mouse on the line, the corresponding temperature and relative free energy values will display.

3. In the figure “Finite Temperature Free Energy Landscape” and the corresponding table, the relative free energy change can be displayed at a given temperature using the sliding bar.

*With the sliding bar on top of the figure, one can select the temperature of interest to examine the relative stability of different polymorphs.