Polymorphic mixture of Rifaximin and its use for the preparation of solid formulations
A Rifaximin polymorphic mixture of α/β form in a relative ratio of 85/15±3 and a process for its preparation. The polymorphic mixture of Rifaximin is for use as a medicament, in particular in the treatment of traveler's diarrhea and hepatic encephalopathy. A pharmaceutical composition comprises the polymorphic mixture of Rifaximin as active ingredient, in particular, a solid formulation, more in particular, a film coated tablet. A polymorphic form of crude wet rifaximin and of purified wet rifaximin their use are used as intermediates in a process for the preparation of Rifaximin polymorphic mixture of α/β form in a relative ratio of 85/15±3.
1. A tablet obtained by a dry granulation and tableting procedure comprising a Rifaximin polymorphic mixture that comprises α and β Rifaximin polymorphs in a α/β relative ratio of 85/15±3,
wherein the Rifaximin polymorphic mixture is characterized by an X-Ray spectrum with characteristic 2theta values at about: 5.32, 5.78, 6.50, 7.24, 7.82, 8.80, 10.50, 11.02, 11.58, 13.08, 14.42, 17.32, 17.68, 18.58, 19.52, 21.04, 21.60, and 21.92.
2. The tablet of claim 1 , further comprising an excipient.
3. The tablet of claim 2 , wherein the excipient is selected from the group consisting of microcrystalline cellulose, sodium starch glycolate, glyceryl palmitostearate, and talc.
4. The tablet of claim 1 further comprising talc, microcrystalline cellulose, glycerol palmitostearate, sodium starch glycolate, or combinations thereof.
5. The tablet of claim 1 further comprising a coating agent.
6. The tablet of claim 5 , wherein the coating agent is polyvinyl alcohol or hydroxypropyl methyl cellulose.
7. The tablet of claim 1 further comprising a plasticizer.
8. The tablet of claim 7 , wherein the plasticizer is selected from the group consisting of polyethylene glycol, dibutyl sebacate, citrate esters, and triacetin.
9. The tablet of claim 1 further comprising an opacifier.
10. The tablet of claim 9 , wherein the opacifier is selected from the group consisting of titanium dioxide, polyvinyl alcohol, and polyethylene glycol.
11. The tablet of claim 1 further comprising a lubricant.
12. The tablet of claim 11 , wherein the lubricant is selected from the group consisting of glyceryl palmitostearate, talc, hydrated silicon dioxide, and a combination thereof.
13. The tablet of claim 1 further comprising a coloring agent.
14. The tablet of claim 13 , wherein the coloring agent is red iron oxide.