Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Carbohydrate doai
Reexamination Certificate
2001-12-20
2003-08-26
Wilson, James O. (Department: 1623)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Carbohydrate doai
C514S054000, C514S167000, C514S169000, C514S171000, C514S172000, C514S843000, C536S102000, C536S103000, C536S123100
Reexamination Certificate
active
06610670
ABSTRACT:
FIELD OF INVENTION
The present invention relates to an inclusion complex formed between cyclodextrin and drospirenone, to methods of providing such an inclusion complex, and to a method of increasing the water solubility of drospirenone by providing such an inclusion complex. Moreover, the present invention relates to the use of said inclusion complex in pharmaceutical compositions for use as a medicament in the treatment of symptoms associated with menopause and in female contraception.
BACKGROUND OF THE INVENTION
Drospirenone (6&bgr;,7&bgr;;15&bgr;,16&bgr;-dimethylene-3-oxo-17&agr;-pregn-4-ene-21,17-carbolactone), which may be prepared substantially as described in e.g. U.S. Pat. No. 4,129,564 or WO 98/06738, is only sparingly soluble in aqueous media at various pH values.
The water solubility of a compound is extremely pertinent with regards to its utility in industry, particularly in the pharmaceutical industry where there is a strong link between water solubility and bioavailability. The therapeutic efficiency of drospirenone may be improved by increasing its overall water solubility, thus providing for routes of administration alternative to those proceeding via the gastrointestinal tract, where absorption is slow and then rapidly cleared from circulating blood by the liver.
Cyclodextrins are known to solubilize nonpolar compounds and improve the absorption of certain compounds by forming complexes with said compounds. The cyclodextrins are frequently derivatized in order to improve the solubility or to accommodate appropriately the compound of interest. However, certain compounds are not well accommodated by the cavity of the some of the cyclodextrin molecules.
Drospirenone, in its uncomplexed form, is known from DE 26 52 761 in which its use as a diuretic compound is disclosed.
U.S. Pat. No. 4,596,795 discloses a complex between &agr;-, &bgr;- and &ggr;-cyclodextrins and derivatives thereof with testosterone, progesterone, and estradiol and the solubility of said complexes.
U.S. Pat. No. 5,885,978 relates to a composition comprising an adrenal cortical steroid and cyclodextrin prepared by clathrating the adrenal cortical steroid in the cyclodextrin using a homomixer.
U.S. Pat. No. 5,376,641 discloses a method of making a steroid water soluble by mixing a steroid and a branched beta cyclodextrin together in water for a period of 4 to 24 hours under ambient conditions.
U.S. Pat. No. 5,376,641 discloses a method for making a steroid water soluble by complexing the steroid with branched &bgr;-cyclodextrin.
U.S. Pat. No. 4,727,064 discloses a method of improving the dissolution properties of a steroid by forming a solid comprising at least one of testosterone, progesterone and estradiol as an inclusion complex with a poly-&bgr;-cyclodextrin and /or hydroxypropyl-&bgr;-cyclodextrin adapted for administration by buccal route.
FR 2 515 187 discloses inclusion complexes between &ggr;-cyclodextrines and various steroids, such as a spironolactone steroid.
WO 96/02277 discloses pharmaceutical compositions containing cyclodextrin-clathrate complexes of steroid sexual hormones for protection against oxidative degradation of steroids.
SUMMARY OF THE INVENTION
The invention relates to an inclusion complex between cyclodextrin and 6&bgr;,7&bgr;;15&bgr;,16&bgr;-dimethylene-3-oxo-17&agr;-pregn-4-ene-21,17-carbolactone (drospirenone).
The invention also relates to methods for producing an inclusion complex between cyclodextrin and drospirenone comprising combining drospirenone and cyclodextrin at a molar ratio of from 0.3:1 to 20:1, preferably 1:1, 2:1, 3:1, 4:1 or 5:1, most preferably 2:1 or 3:1, particularly 3:1.
One object of the present invention is to increase the water-solubility of drospirenone. The present invention thus further relates to methods for improving the solubility of drospirenone, said method comprising forming an inclusion complex between drospirenone and cyclodextrin.
In a further aspect of the invention, pharmaceutical compositions comprising an inclusion complex of drospirenone and cyclodextrin are anticipated. Consequently, the use of the inclusion complex between drospirenone and cyclodextrin as a medicament and for the preparation of a composition for female contraception or for the treatment of menopausal symptoms are defined herein. Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.
DETAILED DESCRIPTION OF THE INVENTION
The term “inclusion complex” is intended to mean a complex wherein at least a moiety of drospirenone has inserted itself, at least partially, into the cavity of cyclodextrin.
In efforts to improve the functional utility of drospirenone, research has led to a new chemical entity, an inclusion complex between cyclodextrin and drospirenone. The cyclodextrin, may be selected from &agr;-cyclodextrin, &bgr;-cyclodextrin, &ggr;-cyclodextrin or derivatives thereof. Preferred embodiments of the present invention are that of a complex between drospirenone and &bgr;-cyclodextrin or derivatives thereof or a complex between drospirenone and &ggr;-cyclodextrin or derivatives thereof, most preferably a complex between drospirenone and &bgr;-cyclodextrin or &ggr;-cyclodextrin, particularly &bgr;-cyclodextrin.
The cyclodextrin, as stated, may be selected from the group comprised of &agr;-cyclodextrin, &bgr;-cyclodextrin or &ggr;-cyclodextrin, i.e. the 6-, 7-, or 8-sugar unit macrocycle, respectively. The cyclodextrin may be modified such that some or all of the primary or secondary hydroxyls of the macrocyle, or both, may be alkylated or acylated. Methods of modifying these alcohols are well known to the person skilled in the art and many derivatives are commercially available. The cyclodextrin may be modified such that one or more of the primary or secondary hydroxyls of the macrocyle, or both, may be alkylated or acylated. Methods of modifying these alcohols are well known to the person skilled in the art and many are commercially available. Thus, some or all of the hydroxyls of cyclodextrin may be substituted with an O—R group or an O—C(O)—R, wherein R is an optionally substituted C
1-6
alkyl, an optionally substituted C
2-6
alkenyl, an optionally substituted C
2-6
alkynyl, an optionally substituted aryl or heteroaryl group. R may be methyl, ethyl, propyl, butyl, pentyl, or hexyl group. Consequently, O—C(O)—R may be an acetate. Furthermore, R may be such as to derivatize cyclodextrin with the commonly employed 2-hydroxyethyl group, or 2-hydroxypropyl group. Moreover, the cyclodextrin alcohols may be per-benzylated, per-benzoylated, or benzylated or benzoylated on just one face of the macrocycle, or wherein only 1, 2, 3, 4, 5, or 6 hydroxyls are benzylated or benzoylated. The hydroxyl groups of cyclodextrin may be per-alkylated or per-acylated such as per-methylated or per-acetylated, or alkylated or acylated, such as methylated or acetylated, on just one face of the macrocycle, or wherein only 1, 2, 3, 4, 5, or 6 hydroxyls are alkylated or acylated, such as methylated or acetylated.
In a preferred embodiment of the invention, the inclusion complex is between &bgr;-cyclodextrin or &ggr;-cyclodextrin and drospirenone. Most preferably, the inclusion complex is between &bgr;-cyclodextrin and drospirenone and in a further interesting embodiment thereof, the &bgr;-cyclodextrin is unmodified.
One or more drospirenone molecules may be included into the cavity of the cyclodextrin molecule. Conversely, one molecule of drospirenone may be included into the cavity of one or more cyclodextrin molecules. The inclusion complex may exist in a variety of molar ratios. The molar ratio between drospirenone and the cyclodextrin is dependent on a variety of physical factors during the formation of the inclusion complex. Furthermore, the molar ratio of the inclusion complex may be transitional and vary during its preparation. Given the inclusion of drospirenone can result from a variety of interactions with any number of functional groups or moieties of drospirenone, t
Backensfeld Thomas
Heil Wolfgang
Lewis Patrick
Millen White Zelano & Branigan P.C.
Schering Aktiengesellschaft
Wilson James O.
LandOfFree
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