Claims
- 1. Nitrofurantoin particulates, wherein:
- (a) said particulates are larger than about 200 mesh size;
- (b) the BET surface area of said particulates is at least about 0.2 M.sup.2 /g;
- (c) the surface of said particulates consists essentially of nitrofurantoin monohydrate crystalline forms; and
- (d) the remaining, inner portion of said particulates is comprised of anhydrous nitrofurantoin, nitrofurantoin monohydrate, or mixtures thereof.
- 2. Nitrofurantoin particulates, according to claim 1, wherein said BET surface area is at least about 0.4 M.sup.2 /g.
- 3. Nitrofurantoin particulates, according to claim 2, wherein said particulates have a size distribution of from about 40 mesh to about 60 mesh.
- 4. Nitrofurantoin particulates, according to claim 1, comprising a surface layer of nitrofurantoin monohydrate.
- 5. Nitrofurantoin particulates, according to claim 4, wherein said particulates are comprised of at least about 50% nitrofurantoin monohydrate.
- 6. Nitrofurantoin particulates, according to claim 5, comprising at least about 90% nitrofurantoin monohydrate.
- 7. A method of making nitrofurantoin particulates, wherein said particulates are larger than about 200 mesh size, the BET surface area of said particulates is at least about 0.2 M.sup.2 /g, and the surface of said particulates consists essentially of nitrofurantoin monohydrate crystalline forms, comprising the steps of:
- (a) preparing a saturated aqueous solution of nitrofurantoin monohydrate;
- (b) adding to said solution anhydrous nitrofurantoin having a particle size larger than about 200 mesh;
- (c) mixing said solution for at least about 5 minutes; and
- (d) filtering said solution.
- 8. A method of making nitrofurantoin particulates, according to claim 7, wherein said anhydrous nitrofurantoin has a particle size distribution of from about 40 mesh to about 60 mesh.
- 9. A method of making nitrofurantoin particulates, according to claim 8, wherein said anhydrous nitrofurantoin is added to said solution at a level of about 100 g per liter of said solution.
- 10. A method of making nitrofurantoin particulates, according to claim 7, wherein said solution is mixed in said step (c) for at least about 6.5 hours.
Parent Case Info
This is a continuation of application Ser. No. 07/707,232, filed on May 20, 1991, now abandoned, which is a continuation of application Ser. No. 07/386,050, filed on Jul. 25, 1989, now abandoned.
US Referenced Citations (12)
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Country |
607590 |
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CAX |
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CAX |
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Entry |
H. Paul et al., "Laboratory Studies with Nitrofurantoin", vol. 56 J. Pharmaceutical Sciences, p. 882 (1967.) |
N. Shah et al., "Effect of Polymers on Dissolution from Drug Suspensions", vol. 65, J. Pharmaceutical Sciences, p. 1618 (1976). |
A. S. Geneidi et al., "Solid Dispersions of Nitrofurantoin, Ethotoin, and Coumarin with Polyethylene Glycol 6000 and Their Coprecipitates with Povidone 25,000", vol. 67, J. Pharmaceutical Sciences, p. 114 (1976). |
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Continuations (2)
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Number |
Date |
Country |
Parent |
707232 |
May 1991 |
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Parent |
386050 |
Jul 1989 |
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