Process for the preparation of and crystalline forms of optical enantiomers of modafinil

1. A dextrorotatory enantiomer of modafinil in a polymorphic form that produces a powder X-ray diffraction spectrum comprising intensity peaks corresponding to interplanar spacings at about 5.23, 5.03, 4.22, and 4.10 (Å).

2. The dextrorotatory enantiomer of modafinil according to claim 1 , wherein the powder X-ray diffraction spectrum further comprises intensity peaks corresponding to interplanar spacings at about 9.63, 4.74, 4.66 and 3.77 (Å).

3. A polymorphic form of the dextrorotatory enantiomer of modafinil that produces a powder X-ray diffraction spectrum comprising reflections at about 16.95, 17.64, 21.06 and 21.67 degrees 2θ.

4. The polymorphic form according to claim 3 , wherein the powder X-ray diffraction spectrum further comprises reflections at about 9.17, 18.69, 19.03 and 23.61 degrees 2θ.

5. A composition consisting essentially of a polymorphic form of the dextrorotatory enantiomer of modafinil that produces a powder X-ray diffraction spectrum comprising intensity peaks corresponding to interplanar spacings of about 5.23, 5.03, 4.22 and 4.10 (Å).

6. The composition according to claim 5 , wherein the powder X-ray diffraction spectrum further comprises intensity peaks corresponding to interplanar spacings of about 9.63, 4.74, 4.66 and 3.77 (Å).

7. A composition consisting essentially of a polymorphic form of the dextrorotatory enantiomer of modafinil that produces a powder X-ray diffraction spectrum comprising reflections at about 16.95, 17.64, 21.06 and 21.67 degrees 2θ.

8. The composition according to claim 7 , wherein the powder X-ray diffraction spectrum further comprises reflections at about 9.17, 18.69, 19.03 and 23.61 degrees 2θ.

9. A Form V polymorph of the dextrorotatory enantiomer of modafinil.

10. A composition comprising the Form V polymorph of claim 9 .

11. A composition comprising the Form V polymorph of claim 9 , wherein said composition is substantially free of other polymorphic forms of the dextrorotatory enantiomer of modafinil.

12. A composition consisting essentially of the Form V polymorph of claim 9 .

13. A pharmaceutical composition comprising one or more pharmaceutically acceptable excipients and the Form V polymorph of claim 9 .

14. A pharmaceutical composition comprising one or more pharmaceutically acceptable excipients and an active ingredient consisting essentially of the Form V polymorph of claim 9 .

15. A process for preparing the Form V polymorph of claim 9 , comprising the steps of: (a) providing a solution of the dextrorotatory enantiomer of modafinil dissolved in a hot solvent; (b) cooling the solution from step (a) to produce crystals; (c) isolate the crystals of said Form V polymorph that are formed in step (b); wherein the solvent of step (a) is selected from 2-pentanone and tetrahydrofuran.