Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1998-08-11
2001-01-09
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Heterocyclic carbon compounds containing a hetero ring...
C424S489000
Reexamination Certificate
active
06172059
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to a novel composition of matter which is a pharmaceutical suspension comprising nevirapine hemihydrate.
(2) Description of the Related Art
Nevirapine, or 11-cyclopropyl-5,11-dihydro-4-methyl-6H-dipyrido[3,2-b:2′,3′-e][1,4]diazepin-6-one, is a known agent for the treatment of infection by HIV-1 (human immunodeficiency virus, type 1), which acts through specific inhibition of HIV-1 reverse transcriptase. Its synthesis and use are described in various publications including, inter alia, U.S. Pat. No. 5,366,972; European Patent Application No. 0 429 987, U.S. patent application Ser. No. 08/515,093 and U.S patent application Ser. No. 08/371,622. Viramune® tablets, a pharmaceutical comprising nevirapine in tablet form, has recently been approved by the U.S. Food and Drug Administration for use in the treatment of HIV-1 infection.
Angel et al. [Proc. 50th Annual Meeting of the Electron Microscopy Society of America, pp. 1326-1327 (1992)] have disclosed that nevirapine exists as the hemihydrate stable form and as the anhydrous metastable form. This same reference describes an attempt to make an aqueous suspension of nevirapine, suitable for pediatric use, from the anhydrous form of the compound. The attempt was unsuccessful because, when formulated in aqueous suspension, the anhydrous nevirapine slowly converted to the hemihydrate form, yielding crystals of the hemihydrate which, over time, grew so large as to adversely affect drug dissolution and pharmaceutical performance.
SUMMARY OF THE INVENTION
The invention is an aqueous suspension of the hemihydrate form of nevirapine. It has been found, unexpectedly, that, when placed in aqueous suspension, the crystal size of the hemihydrate remains stable over time. For this reason, aqueous suspensions of nevirapine hemihydrate are pharmaceutically acceptable.
REFERENCES:
patent: 5366972 (1994-11-01), Hargrave et al.
Angel et al., Proc. 50th Annual Meeting of the Electron Microscopy Society of America. pp. 1326-1327, 1992.
Grozinger Karl G.
Hawi Amale A.
Boehringer Ingelheim Pharmaceuticals Inc.
Devlin Mary-Ellen M.
Page Thurman K.
Pulliam Amy E
Raymond Robert P.
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