Methods for indexing solid forms of compounds
AssigneeAptuit (West Lafayette), LLC
InventorRichard B. McClurg
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Abstract
The methods of the invention determine the unit cell parameters of a crystalline solid form using diffraction data and applying an algorithm. Using the algorithm, the unit cell parameters may be determined, which may allow one to distinguish between different crystalline solid forms of a substance.
Claims14
A method for determining the unit cell parameters of a crystalline solid form of a compound, which method comprises:
- i. using a diffractometer to generate powder diffraction data for a solid crystalline substance;
- and
- ii. determining the unit cell parameters of the substance by performing a Triads Algorithm to identify one or more sets of values of unit cell parameters of the crystalline solid form.
A method for determining the unit cell parameters of a crystalline solid form of a compound, which method comprises using an X-ray powder diffractometer to generate XRPD data for a solid crystalline substance;
- and
- a. generating a peak list from the XRPD data of the crystalline solid substance;
- b. choosing three basis peaks and labeling them A, B, and C;
- c. using (001), (010), and (100), respectively, as Miller indices, to calculate the reciprocal cell length parameters (a*,b*,c*) from κC, κB, and κA;
- d. determining acceptable ranges for the vector sums of pairs of C, B, and A using any of the following ranges:
- κB−κC≦κB+C≦κB+κC, i.
- κA−κC≦κA+C≦κA+κC, and ii.
- κA−κB≦κA+B≦κA+κB;
- iii.
- e. choosing three peaks from the ranges in (d) and labeling as B+C, A+C, and A+B;
- f. using (011), (101), and (110), respectively, as Miller indices, to calculate the cosines of the reciprocal cell angle parameters of (α*,β*,γ*) from κB+C, κA+C, and κA+B;
- g. calculating peak positions;
- h. determining whether the cell is consistent with the entire peak list;
- and
- i. refining the unit cell parameter.
A method for distinguishing between crystalline solid forms of different samples of a substance, which comprises:
- for each sample, generating an X-ray powder diffraction pattern of a solid crystalline substance;
- determining the unit cell parameters of each substance by performing a Triads Algorithm to identify one or more sets of values of unit cell parameters of the crystalline solid forms, and comparing the one or more sets of values of unit cell parameters of the crystalline solid forms.
A method of sorting, screening, or ranking crystalline solid forms, which comprises:
- for each sample, generating an X-ray powder diffraction pattern of the solid crystalline form;
- determining the unit cell parameters of the substance by performing a Triads Algorithm to identify one or more sets of values of unit cell parameters of the crystalline solid form, and sorting, screening, or ranking the crystalline solid forms based on the unit cell parameters, character, and/or extinction symbol of each crystalline solid form.
Dependencies are inferred from the claim text.