Title:
THE PROCESS OF MANUFACTURING PHARMACEUTICAL GRADE TANNATES
Document Type and Number:
WIPO Patent Application WO2002005746
Kind Code:
A3
Abstract:
Antihistamines are available in the form of free bases as well as salts i.e. hydrochloride, maleate, tannate etc. Frequently, it is necessary to utilise antihistamines in the form of tannate salt because such salts are generally quite stable and may be administered in such from without untoward side effects. Tannic acid, also known as tannin, is a well known naturally occurring substance. Tannic acid, which is available commercially, usually contain about 5 % of water, has a molecular weight of about 1700 and is typically produced from Turkish or Chinese nutgall. Antihistamine tannates, presently manufactured commercially, are relatively impure. Such tannates are prepared by the reaction of antihistamine free base with tannic acid and using a volatile solvent, isopropanol (IPA). The yield is only fair (around 70 %) and decomposition products e.g. 2-5 % along with significant amount of volatile solvent, isopropanol (6-10 %) remains with the product, which cannot be removed. According to present invention, for specific types of tannates, isopropanol (IPA) is removed by adding water while stirring and dispersing the wet cake of tannate. It is then filtered and the tannate residue is dried to obtain pharmaceutical grade tannate. Tannates like chlorpheniramine tannate and pyrilamine tannates have been prepared by this method.
Inventors:
KHAMAR BAKULESH MAFATLAL (IN)
SRINIVASAN CHIDAMBARAM VENKATE (IN)
MITRA JAYATI (IN)
SRINIVASAN CHIDAMBARAM VENKATE (IN)
MITRA JAYATI (IN)
Application Number:
PCT/IB2001/001252
Publication Date:
May 02, 2002
Filing Date:
July 13, 2001
Export Citation:
Assignee:
CADILA PHARMACEUTICALS LTD (IN)
KHAMAR BAKULESH MAFATLAL (IN)
SRINIVASAN CHIDAMBARAM VENKATE (IN)
MITRA JAYATI (IN)
KHAMAR BAKULESH MAFATLAL (IN)
SRINIVASAN CHIDAMBARAM VENKATE (IN)
MITRA JAYATI (IN)
International Classes:
A61K47/12; (IPC1-7): C07C69/88
Foreign References:
| US3282789A | 1966-11-01 | |||
| US5663415A | 1997-09-02 |
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