Polymorphs of dolutegravir and salts thereof

1. Dolutegravir sodium Form-L9 characterized by a powder X-Ray diffraction pattern having one or more peaks at about 6.1, 8.6, 12.1, 13.4, 17.1, 18.6, 19.3, 22.4, 23.8, 25.4 and 26.3±0.2° 2θ.

2. Dolutegravir sodium Form-L9 of claim 1 , further characterized by one or more of a powder X-Ray diffraction (PXRD) pattern substantially in accordance with FIG. 1 , a differential scanning calorimetry (DSC) substantially in accordance with FIG. 2 , and a thermo gravimetric analysis (TGA) substantially in accordance with FIG. 3 .

3. A process for the preparation of dolutegravir sodium Form-L9, which comprises:

a) suspending or mixing dolutegravir in 1-pentanol;

b) adding sodium hydroxide to step a) at a suitable temperature;

c) stirring the reaction mass at a suitable temperature;

d) isolating the dolutegravir sodium and drying the wet solid at a suitable temperature; and

e) exposing the dried compound under atmosphere air or humid air to obtain dolutegravir sodium Form-L9.

4. The process of claim 3 , wherein the sodium hydroxide is an aqueous solution of sodium hydroxide.

5. The process of claim 3 , wherein the step e) is carried out under atmospheric air.

6. The process of claim 3 , wherein the step e) is carried out for about 4 hrs to 16 hrs.

7. A process for preparation of dolutegravir sodium Form-L9, which comprises de-solvating dolutegravir sodium 1-pentanol solvate by heating at a suitable temperature of about 110° C. to about 135° C., for a sufficient period of time under vacuum to provide dolutegravir sodium Form-L9, wherein the dolutegravir sodium 1-pentanol solvate is characterized by a powder X-Ray diffraction pattern having one or more peaks at about 5.32, 7.50, 9.16, 11.46, 12.98, 13.72, 15.02, 15.84, 16.42, 18.60, 19.58, 20.08, 20.50, 21.00, 21.98, 23.06, 23.90, 24.46, 25.78, 26.28, 27.18 and 28.36±0.2° 2θ.

8. The process of claim 7 , wherein the heating is carried out for a period of about 4 hrs to 12 hrs.

9. Dolutegravir sodium Form-L12 characterized by a powder X-Ray diffraction pattern having one or more peaks at about 5.32, 7.50, 9.16, 11.46, 12.98, 13.72, 15.02, 15.84, 16.42, 18.60, 19.58, 20.08, 20.50, 21.00, 21.98, 23.06, 23.90, 24.46, 25.78, 26.28, 27.18 and 28.36±0.2° 2θ.

10. Dolutegravir sodium Form-L12 of claim 9 , further characterized by one or more of a powder X-Ray diffraction (PXRD) pattern substantially in accordance with FIG. 10 , a differential scanning calorimetry (DSC) substantially in accordance with FIG. 11 , and a thermo gravimetric analysis (TGA) substantially in accordance with FIG. 12 .

11. A process for preparation of dolutegravir sodium Form-L12, which comprises;

a) suspending or mixing dolutegravir in 1-pentanol or its aqueous solution;

b) adding sodium hydroxide to step a) at a suitable temperature; and

c) isolating dolutegravir sodium Form-L12.

12. The process of claim 11 , wherein the sodium hydroxide is an aqueous solution of sodium hydroxide.

13. The process of claim 11 , wherein the dolutegravir sodium Form-L12 is isolated by filtration.

14. Dolutegravir sodium Form-L10 characterized by a powder X-Ray diffraction pattern having one or more peaks at about 5.94, 6.30, 7.22, 8.10, 10.58, 12.20, 13.08, 14.12, 15.74, 16.48, 17.88, 18.40, 19.74, 21.72, 23.40, 24.72, 25.24, 26.44, 27.02, 28.60 and 29.54±0.2° 2θ.

15. Dolutegravir sodium Form-L10 of claim 14 , further characterized by one or more of a powder X-Ray diffraction (PXRD) pattern substantially in accordance with FIG. 4 , a differential scanning calorimetry (DSC) substantially in accordance with FIG. 5 , and a thermo gravimetric analysis (TGA) substantially in accordance with FIG. 6 .

16. A process for preparation of dolutegravir sodium Form-L10, which comprises:

a) suspending or mixing dolutegravir in isopentanol or its aqueous solution;

b) adding sodium hydroxide to step a) at a suitable temperature; and

c) isolating dolutegravir sodium Form-L10.

17. A pharmaceutical composition comprising:

dolutegravir sodium or solvates of dolutegravir; and

at least one pharmaceutically acceptable excipient,

wherein the dolutegravir sodium and solvates of dolutegravir is one of

Form-L9 characterized by a powder X-Ray diffraction pattern having one or more peaks at about 6.1, 8.6, 12.1, 13.4, 17.1, 18.6, 19.3, 22.4, 23.8, 25.4 and 26.3±0.2° 2θ,

Form-L12 characterized by a powder X-Ray diffraction pattern having one or more peaks at about 5.32, 7.50, 9.16, 11.46, 12.98, 13.72, 15.02, 15.84, 16.42, 18.60, 19.58, 20.08, 20.50, 21.00, 21.98, 23.06, 23.90, 24.46, 25.78, 26.28, 27.18 and 28.36±0.2° 2θ, and

Form-L10 characterized by a powder X-Ray diffraction pattern having one or more peaks at about 5.94, 6.30, 7.22, 8.10, 10.58, 12.20, 13.08, 14.12, 15.74, 16.48, 17.88, 18.40, 19.74, 21.72, 23.40, 24.72, 25.24, 26.44, 27.02, 28.60 and 29.54±0.2° 2θ.