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US 7,678,903 B2Granted
Process for the preparation of levofloxacin hemihydrate
AssigneeMatrix Laboratories Limited
InventorsSatya-naryana Chava, Seeta Ramanjaneyulu Gorantla, Venkata Panakala Rao
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Abstract
The present invention relates to an improved process for the preparation of Levofloxacin hemihydrate by adjusting the moisture content of the solvent to about 12% to about 20% during crystallization.
Claims13
A process for the preparation of Levofloxacin hemihydrate comprising the steps of:
- reacting (S)-(-)9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4] benzoxazine-6-carboxylic acid with N-methyl piperazine in n-butanol at a temperature of 120° C. to 125° C.;
- removing the n-butanol under vacuum at a temperature below 100° C.;
- dissolving the residue in a mixture of toluene-chloroform and removing insolubles therefrom;
- removing the toluene-chloroform mixture and adding isopropanol;
- adding a pre-determined quantity of water and mixing for about 5 min to about 30 min;
- cooling to a temperature of about 15° C. to about 35° C.;
- and
- isolating and drying the product.
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A process for the preparation of Levofloxacin hemihydrate free of Levofloxacin monohydrate, comprising the steps of:
- providing an amount of (S)-(−)9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7-H-pyrido[1,2,3-de][1,4] benzoxazine-6-carboxylic acid;
- suspending the same in n-butanol to form a first solution;
- adding a molar excess amount of N-methyl piperazine to the first solution;
- heating the first solution to a temperature substantially the same as the reflux temperature of the n-butanol;
- removing the n-butanol at a temperature below 100° C. to form a residue;
- washing the residue with a quantity of isopropanol to form a second solution;
- heating the second solution to a temperature substantially the same as the reflux temperature of the second solution;
- adding a pre-determined quantity of water to the second solution for a sufficient amount of time to form the Levofloxacin hemihydrate, wherein the amount of water added is equivalent to between about 12% to 20% of the quantity of isopropanol;
- and
- isolating the Levofloxacin hemihydrate.
7 more elements
Dependencies are inferred from the claim text.