Oral 2-methyl-thieno-benzodiazepine formulation

Details Oral 2-methyl-thieno-benzodiazepine formulation Oral 2-methyl-thieno-benzodiazepine formulation

1998-08-31

2001-02-20

Spear, James M. (Department: 1615)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Tablets, lozenges, or pills

C424S482000, C424S494000, C424S497000, C514S772300, C514S781000

Reexamination Certificate

active

06190698

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention provides an improved pharmaceutically elegant tablet formulation of 2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5] benzodiazepine, hereinafter referred to as olanzapine, and processes for the preparation thereof.
Olanzapine has shown great promise in the treatment of psychotic patients and is currently being evaluated for that purpose. Certain tablet formulations of olanzapine are known, as described in U.S. Pat. No. 5,229,382. However, improved oral formulations were desired in light of the moisture sensitive, metastable nature of olanzapine, the tendency of olanzapine to undesirably discolor in the known tablet formulation, and due to the surprisingly potent nature of olanzapine.
The presently claimed invention provides a pharmaceutically elegant solid oral formulation comprising olanzapine as an active ingredient intimately mixed with a bulking agent, binder, disintegrant, a dry binder to provide friability, and a lubricant;
wherein such solid oral formulation is coated with polymer selected from the group consisting of hydroxypropyl methyl cellulose, hydroxyethyl cellulose,
methylhydroxyethylcellulose, sodium carboxymethylcellulose, hydroxypropylcellulose, polyvinyl pyrrolidone, dimethylaminoethyl methacrylatemethylacrylate acid ester copolymer, ethylacrylate-methylmethacrylate copolymer, methylcellulose, and ethylcellulose.
It is particularly preferred that the polymer coat does not contain polyethylene glycol.
Further, the invention provides a method for preparing pharmaceutically elegant, stable solid oral olanzapine formulations having a polymer coat selected from the group consisting of hydroxypropyl methyl cellulose, hydroxyethyl cellulose, methylhydroxyethylcellulose, sodium carboxymethylcellulose, hydroxypropylcellulose, polyvinyl pyrrolidone, dimethylaminoethyl methacrylatemethylacrylate acid ester copolymer, ethylacrylate-methylmethacrylate copolymer, methylcellulose, and ethylcellulose, comprised of using a high shear aqueous wet granulation with fluid bed drying process.
DETAILED DESCRIPTION OF THE INVENTION
Olanzapine, a potent compound showing promising activity for use in treating psychotic patients, tends to be metastable, undergo pharmaceutically undesired discoloration, and demands care to assure homogeniety of the finished solid formulation.
Applicants have discovered that olanzapine undergoes undesirable discoloration when contacted with certain excipients including powder blends. Further, the discoloration is exacerbated by ambient air conditions, at elevated temperatures, and by moist environments.
Although the discoloration phenomenon does not produce an increase in the number of total related substances, the browning and mottling appearance is not generally considered pharmaceutically acceptable for commercial purposes. Further, the discoloration is particularly disturbing when a tablet formulation is administered to a psychotic patient, which patient may be especially troubled by the changing appearance of their medication.
Applicants have discovered that coating the solid oral formulation with a polymer selected from the group consisting of hydroxypropyl methyl cellulose, hydroxyethyl cellulose, methylhydroxyethylcellulose, sodium carboxymethylcellulose, hydroxypropylcellulose, polyvinyl pyrrolidone, dimethylaminoethyl methacrylatemethylacrylate acid ester copolymer, ethylacrylate-methylmethacrylate copolymer, methylcellulose, and ethylcellulose as a coating or subcoating provides a uniform, physical stability and effectively prevents the undesired discoloration phenomenon in the formulation. The formulation is most preferredly in a tablet form; however, granule formulation and the like are desired as well.
Most preferred polymer coats are hydroxypropyl methyl cellulose, hydroxypropylcellulose, methylcellulose, and ethylcellulose. An especially preferred polymer coat is hydroxypropyl methylcellulose.
It is especially preferred that the formulation contain the most stable anhydrous form of olanzapine, referred to herein as Form II; however, other forms of olanzapine are contemplated. Form II has a typical x-ray powder diffraction pattern as represented by the following interplanar spacings:
d
10.2689
8.577
7.4721
7.125
6.1459
6.071
5.4849
5.2181
5.1251
4.9874
4.7665
4.7158
4.4787
4.3307
4.2294
4.141
3.9873
3.7206
3.5645
3.5366
3.3828
3.2516
3.134
3.0848
3.0638
3.0111
2.8739
2.8102
2.7217
2.6432
2.6007
A typical example of an x-ray diffraction pattern for Form II is as follows wherein d represents the interplanar spacing and I/I
1
represents the typical relative intensities:
d
I/I
1
10.2689
100.00
8.577
7.96
7.4721
1.41
7.125
6.50
6.1459
3.12
6.071
5.12
5.4849
0.52
5.2181
6.86
5.1251
2.47
4.9874
7.41
4.7665
4.03
4.7158
6.80
4.4787
14.72
4.3307
1.48
4.2294
23.19
4.141
11.28
3.9873
9.01
3.7206
14.04
3.5645
2.27
3.5366
4.85
3.3828
3.47
3.2516
1.25
3.134
0.81
3.0848
0.45
3.0638
1.34
3.0111
3.51
2.8739
0.79
2.8102
1.47
2.7217
0.20
2.6432
1.26
2.6007
0.77
The x-ray diffraction patterns set out herein were obtained using a Siemens D5000 x-ray powder diffractometer having a copper K
&agr;
radiation source of wavelength, &lgr;=1·541 Å.
The formulation of the invention preferredly contains substantially pure Form II as the active ingredient.
As used herein “substantially pure” refers to Form II associated with less than about 5% undesired polymorphic form of olanzapine (herein referred to as “Undesired Form”), preferably less than about 2% Undesired Form, and more preferably less than about 1% Undesired Form. Further, “substantially pure” Form II will contain less than about 0.5% related substances, wherein “related substances” refers to undesired chemical impurities or residual solvent or water. In particular, “substantially pure” Form II preferably contain less than about 0.05% content of acetonitrile, more preferably, less than about 0.005% content of acetonitrile. Additionally, Form II preferredly contain less than 0.5% of associated water.
As used herein, the term “mammal” shall refer to the Mammalia class of higher vertebrates. The term “mammal” includes, but is not limited to, a human. The term “treating” as used herein includes prophylaxis of the named condition or amelioration or elimination of the condition once it has been established.
Form II is the most stable anhydrous form of olanzapine known and is therefore important for the commercial development of pharmaceutically elegant formulations. Olanzapine may form an undesired crystal form in the presence of certain solvents and excipients, therefore, in making the compositions of the invention it is most desired to prepare the formulation using a method which does not require dissolution of the olanzapine substance. The desired Form II can be converted to less desirable polymorphic forms by contact with methylene chloride, for example. Additionally, for example, polyethylene glycol contact with the olanzapine substance produces undesired discoloration, particularly under moist conditions.
Applicants believe that a dry blend direct compression process or dry granulated processes for preparing solid oral formulations create a greater chance that poor dose uniformity will occur. In light of the potent nature of olanzapine, consistent dose uniformity is imperitive. In accordance with this invention, Applicants have discovered that a high shear aqueous wet granulation with fluid bed drying is the most effective method for preparing pharmaceutically elegant, stable, oral olanzapine formulations.
Uncoated tablets stored at ambient conditions (approximately 23° C. and 40% relative humidity) in amber, high density polyethylene bottles do not show signs of discoloration after 24 months; however, if the bottle is opened such that the tablets are exposed to open air ambient conditions then discoloration occurs within 5 days.
A new solid oral formulation was prepared that used a hydroxypropropyl methylcellulose subcoating and a white color coating. The new formulation did not discolor after 90 days of open dish storage a

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