Field of the Invention
The present invention relates to a process for producing a crystalline salt. More
particularly, a crystalline variable hydrate of (s) - ( 3 -pyridine carboxamide, 6 - [ 4 - [ 2
[ [3- ( 9 h - carbazol - 4 - yloxy )-2-hydroxypropyl ] amino] - 2 - methylpropyl ]
phenoxy ]) - hemi-succinate salt
and pharmaceutically acceptable salts thereof, useful as selective 03 receptor agonists,
were disclosed by Heath, et at., in European Patent Publication No. 817,627 (Heath).
Example 126 from Heath disclosed the synthesis of a hemi-succinate salt of a
formula II compound having the structure:

hereafter referred to as "SAM Classic".
Said synthetic procedures described the production of an "amorphous form" of
SAM Classic "containing only trace residual ethanol". Heath described the production of
the amorphous SAM Classic by solvent exchange of the ethanol in the crystalline
ethanolic solvate of SAM Classic with water. In particular, Heath taught that 'The
mixture (from the water slurry) was vacuum filtered, and the filter cake was washed with
water (3x 100 ml). The solid was air dried under vacuum for approximately 2 hours then
in a vacuum oven (65°C) overnight. This gave (amorphous) product as an off white
solid." Thus, Heath discloses that in die process of drying the wet cake material, the
crystal structure of the initially isolated material (present as a wet cake) collapsed to form
the amorphous SAM Classic.

Poorly crystalline materials, in particular amorphous materials, are typically less
desirable than highly crystalline materials for formulation processing. In addition, it is
generally not desirable to formulate pharmaceuticals containing substantial amounts of
organic solvent due to potential solvent toxicity to the recipient thereof and changes in
potency of the pharmaceutical as a function of the solvent. Although the amorphous
SAM Classic prepared by the procedures taught in '474 could be used as a
pharmaceutical, it would be highly desired and advantageous to find a stable crystalline
form of SAM Classic that did not contain substantial amounts of organic solvent within
its crystal structure which could be reproducibly and efficiently prepared on a commercial
scale.
Surprisingly, and in accordance with the invention, it has now been discovered
that a crystalline hydrate of SAM Classic is capable of reproducible production, isolation
and formulation on a commercial scale, is sufficiently stable for use in oral formulations,
and can be produced and isolated in a highly crystalline state.
Brief Summary of the Invention
The present invention relates to a crystalline variable hydrate of (S)-(3-
pyridinecarboxamide,6-[4-[2-[[3-(9H-carbazol-4-yloxy)-2-hydroxypropylJamino]-2-
methylpropyl]phenoxy])-hetni-succinate salt wherein the water content of said hydrate by
weight is between 6 and 11% when measured at 22±5°C and between 10-80% relative
humidity. This crystalline material is hereafter referred to "SAM Classic Hydrate".
The present invention further relates to SAM Classic Hydrate having an X-ray
diffraction pattern which comprises the following peaks: 7.6 ± 0.1 and 8.8 ±0.1° in 20;
when the pattern is obtained at 20-25°C and 25-30% relative humidity (RH) using a
copper radiation source (CuKa; X= 1.54056 A).
In another embodiment, the present invention relates to a pharmaceutical
composition containing SAM Classic Hydrate and a pharmaceutical carrier. In still
another embodiment, the pharmaceutical compositions of the present invention may be
adapted for use in treating obesity and/or Type II diabetes.
Moreover, the present invention relates to methods for treating obesity and/or
Type II diabetes which comprise administering to a patient in need thereof an effective
amount of SAM Classic Hydrate.
In addition, the present invention is related to SAM Classic Hydrate for treating
obesity and/or Type II diabetes. In yet another embodiment, the present invention relates
to the use of SAM Classic Hydrate for the manufacture of a medicament for the treatment
of obesity and/or Type II diabetes.
Brief Description of the Figures
Fig ure 1 is a representative XRD pattern for SAM Classic Hydrate.
Detailed Description of the Invention
For the purposes of the present invention, as claimed herein, the following terms
are defined below.
The term "pharmaceutical" when used herein as an adjective means substantially
non-deleterious.
The term "patient" as used herein refers to humans and non-human animals such
as compan ion animals (dogs, cats, horses and the like). A preferred patient is a human.
The terms 'treating" and "treat" as used herein means alleviating, ameliorating,
preventing, prohibiting, restraining, slowing, stopping, or reversing the progression or
severity of a pathological condition, or sequela thereof, described herein.
The term "a patient in need thereof is a patient suffering from the claimed
pathological condition or sequela thereof as determined by medical diagnosis, i.e., as
determined by the attending physician.
As used herein, the term "effective amount" means an amount of SAM Classic
Hydrate that is capable of treating the conditions described herein.
According to Heath, removal of the water from the wet cake precursor to the
amorphous SAM Classic described therein via air drying under vacuum for approximately
2 hours then in a vacuum oven at 65°C overnight caused the crystal structure of this
precursor to collapse. Thus, Heath suggests that the crystal structure of SAM Classic
Hydrate is not stable when prepared using the standard laboratory/manufacturing
techniques described therein and, therefore, not suitable for development as the active
pharmaceutical ingredient (API). As described herein, Applicants have found
commercially relevant methods for the preparation and isolation of SAM Classic Hydrate.
Characterization of SAM Classic Hydrate
Various methods, including moisture sorption analysis, Karl Fischer analysis, X-
ray powder diffraction (XRD) and ' ^C solid-state nuclear magnetic resonance (SSNMR),
are used to characterize SAM Classic Hydrate.
The moisture sorption profile for SAM Classic Hydrate reveals that it is a non-
stoichiometric hydrate. The SAM Classic Hydrate crystal structure retains approximately
6-11% water between 10 and 80% relative humidity. The hydrate rapidly equilibrates
with the atmosphere, such that the water content observed by analytical techniques is a
function of the relative humidity at which the sample was equilabrated.
The water content of SAM Classic Hydrate may be determined by volumetric Karl
Fischer titration employing a suitable Karl Fischer (KF) titration system, e.g., a
Metrohm® system. Water content, via KF, is determined via the quantitative reaction of
water with iodine and sulfur dioxide while in the presence of alcohol and an organic base
such as pyridine. The amount of water is quantitated by end-point determination using an
appropriately calibrated titrant. Method Conditions: Standard - Purified water; Titer -
Hydranal Composite 2K Pyridine-Free reagent, or AquaStar Comp2 Pyridine-Free reagent
or equivalent (2 mg/mL); Volumetric Flow Rate - 5 ml/min; Agitator Speed - the
maximum speed at which air bubbles are not being created in the titration vessel.
Procedure: Transfer an aliquot of sample (200 mg or more) to the titration vessel.
Completely dissolve the sample in anhydrous methanol prior to analysis. Perform first
titration. Perform a second titration using approximately the same amount of SAM
Classic Hydrate employed in the first run. Calculate the average of the two results.
Calculations:
% Water = [([T] x Vtiter)/Wtsampie] x 100%
[T] = Titer concentration
^titer = Volume of titer used in the titration
WtSample= Weight of sample in mg
The X-ray powder diffraction patterns are obtained on a Siemens D5000 X-ray
powder diffractometer which is equipped with a CuKa source (A. = 1.54056 A) operated at
50 kV and 40 mA with a Kevex solid state Si(Li) detector. The samples are scanned from
4 to 40° in 26 at 3.0 seconds per step size of 0.02 ° with 1 mm divergence and receiving
slits and a 0.1 mm detector slit. The dry powder is dusted onto a low background sample
holder for analysis at 20-25°C and 25-30% relative humidity (RH).
A representative XR.D trace of SAM Classic Hydrate is shown in Figure 1. The
XRD pattern features sharp peaks and a flat baseline, indicative of highly crystalline
material. The angular peak positions in 20 and corresponding I/Io data for all peaks with
intensities equal to or greater than 10% of the largest peak are tabulated in Table 1. All
data in Table 1 is expressed with an accuracy oft 0.1° in 20.
It is well known in the crystallography art that, for any given crystal form, the
relative intensities of the diffraction peaks may vary due to preferred orientation resulting
from factors such as crystal morphology. Where the effects of preferred orientation are
present, peak intensities are altered, but the characteristic peak positions of the polymorph
are unchanged. See, e.g., The United States Pharmacopeia #23, National Formulary #18,
pages 1843-1844, 1995. Furthermore, it is also well known in the crystallography art that,
for any given crystal form, the angular peak positions may vary slightly. For example,
peak positions can shift due to a variation in the temperature or humidity at which a
sample is analyzed or sample displacement. In the present case, a peak position
variability of ± 0.1° in 29 will take into account these potential variations without
hindering the unequivocal identification of SAM Classic Hydrate.
Based on peak intensities as well as peak positions, SAM Classic Hydrate may be
identified by the presence of peaks at 7.6 ± 0.1 and 8.8 ± 0.1° in 26; when the pattern is
obtained at 20-25°C and 25-30% relative humidity (RH) using a copper radiation source
(CuKa; X.= 1.54056 A). The presence of the SAM Classic Hydrate may be further verified
by peaks at 13.1 ±0.1 and 15.5 ± 0.1° in 29; when the pattern is obtained as described
above and even further verified by the presence of peaks at 8.0 ± 0.1, 11.0 ± 0.1, 13.3 t
0.1, 13.8 ± 0.1, and 15.3 ± 0.1° in 26; when the pattern is obtained as described above.
'^C SSNMR analysis is performed with a Varian Unity Inova 400 MHz
spectrometer operating at a carbon frequency of 100.578 MHz, using high-power proton
decoupling, cross polarization (CP) and magic angle spinning (MAS) at 7.0 kHz.
Acquisition parameters are as follows: 90° proton r.f. pulse width 4.0 us, contact time 1.5
ms, pulse repetition time 5 s, spectral width 50 kHz, and acquisition time 50 ms.
Chemical shifts, expressed as parts per million, are referenced to the methyl group of
hexamethylbenzene (5 = 17.3 ppm) by sample replacement. The magic angle is adjusted
by optimizing the sidebands of the 7*Br signal of KBr as described by Frye and Maciel
(Frye J. S. and Maciel G. E., J. Magn. Resort., 1982, 48, 125).
SAM Classic Hydrate may be identified by the presence of isotropic peaks at: 59.8
± 0.1, 111.4 ± 0.1 and 151.4 ± 0.1 ppm when the sample has been equilibrated at 33%
R.H. prior to data collection. SAM Classic Hydrate is further characterized by solid-state
13CNMR resonances at 99.2 ±0.1, 102.4 ±0.1, 134.9 ±0.1, 146.9 ±0.1 and 149.2 ±0.1
ppm when the sample has been equilibrated at 33% R.H. prior to data collection.
The amount (weight percentage) of solvent, such as methanol, ethanol or ethyl
acetate, present in the crystalline material may be determined by headspace gas
chromatography with flame ionization detection. A sample of the crystalline solid (50
mg) is weighed in a headspace vial and dissolved in 2 mL of dimethylsulfoxide. The vial
is incubated at 80°C for 5 minutes and then analyzed using a DB624 column (30 meter,
0.53 mm i.d., 3 micron film thickness). The column temperature is held at 40°C for 10
minutes to elute the solvents of interest, then the oven temperature is increased to 240°C
to elute the sample solvent peak. The GC utilizes helium as a carrier gas at a flow of
approximately 5 ml/minute. The inlet temperature is set to 220°C with a split ratio of 1:5
and injection volume of i ml The detector temperature is 250°C. The amount of
solvent is determined by comparison to solvent standards prepared at known
concentrations. A linear least squares calibration curve is constructed using standard
concentrations (in mg/mL) and standard peak areas. The solvent peak areas in the sample
injections are compared to the calibration curve to determine the concentration of solvent
in each of the sample injections. The percentage of solvent is calculated using the
following formula:
%solvent = (amount solvent found in mg/mL)(2.0mL) X 100
mg sample
The amount (weight percentage) of chemical impurities present in the crystalline
material may be determined using reversed-phase HPLC with UV detection. A sample of
the crystalline solid (approximately 10 mg) is weighed into a 25-ml volumetric flask and
diluted with 70/30 (v/v) mixture of methanol/water. An aliquot of this solution is assayed
using a Zorbax SB-Phenyl column (25 cm X 4.6 mm I.D., 5 micron particles). The
injection volume is 5 microiiters with an autosampler temperature of 5°C. The detector
wavelength is 240 nm and the column flow rate is 1.0 ml/minute. The following gradient
solvent system is used:
A: 50% Methanol : 50% Water: 0.1% Trifluoroacetic Acid
B: 75% Methanol : 25% Water : 0.1% Trifluoroacetic Acid
The area percentage of the impurities is calculated using the following formula
%Total Impurities = Sum of the impurity peak areas X 100
Total of all peak areas
Synthesis
The crystalline ethanol solvate of SAM Classic (719.35 g) is combined with 5.4 L
of deionized water. The resulting slurry is stirred at ambient temperature for
approximately 25 hours. The slurry is filtered using nitrogen pressure. The filter cake is
rinsed with 2.165 L of water. The filter cake is dried at ambient temperature under a
purge of nitrogen that had been bubbled through a saturated solution of potassium acetate
in water to maintain a constant humidity. The nitrogen going into the filter has a relative
humidity of 22.9% and is at 15 PSI of pressure. The filter cake is dried until the % water
is 8.5 to 11% as measured by KF analysis as described herein. After approximately 112
hours, the KF is 8.85% and 666.20 g of SAM Classic Hydrate is obtained.
Formulation
The SAM Classic Hydrate of the present invention is preferably formulated in a
unit dosage form prior to administration to the recipient patient. SAM Classic Hydrate is
preferably formulated employing a dry blend process. Although SAM Classic Hydrate on
its own has very poor flow that could have lead to flowability (cohesiveness of the
powder) problems during filling (leading to poor control on weight uniformity) and/or
homogeneity problems after mixing, the formulations described herein have acceptable
mixing and uniformity attributes, even with the high strength.
Sieve partially pregelitinized starch through a 10 mesh screen. Add the
pregelatinized starch to a tumble bin. Add SAM Classic Hydrate (API) to tumble bin by
layering API in between the starch. Mix for 15 minutes at 13 rpm. Pass the resultant
mixture through a Comill (screen size: -610 urn). Transfer mixture back to tumble bin
and mix for 30 minutes at 13 rpm. Sieve the starch flowable powder (5% silicon) through
a 10 mesh screen and add to mixture in tumble bin. Mix for 15 minutes at 13 rpm. Fill
into size 0 capsules. Refrigerate filled capsules in sealed foil bags at 2-8°C.
Demonstration of Function
SAM Classic free base was disclosed in WO 98/09625 (Example 87 therein), the
contents of which are herein incorporated by reference. In the "Functional. Agonist B3
assay", this free base material was described as having
at least 30% ... of isoproterenors response at a single dose
of 50 mmol. Dose response titrations on the agonists
described reveal EC50 values <10 mM ....
When screened against the B j and B2 receptors in the
functional assay, dose titration experiments indicate that
greatly reduced or no receptor stimulation is observed with
the compounds of the invention.
Utilities
The diseases, disorders or conditions for which SAM Classic Hydrate is useful in
treating include, but are not limited to, Type 2 diabetes mellitus and obesity. Human
patients in need of obesity and/or Type 2 diabetes treatment are typically those with a
body mass index (BMI) >30 or those with a BMI >27 when co-morbidities, e.g.,
hypertension, high cholesterol, heart disease or diabetes are present.
Dose
The specific dose administered is determined by the particular circumstances
surrounding each situation. These circumstances include: the route of administration
(preferably oral), the prior medical history of the recipient, the pathological condition or
symptom being treated, the severity of the condition/symptom being treated, and the age
of the recipient. The recipient patient's physician should determine the therapeutic dose
administered in light of the relevant circumstances. Generally, an effective minimum
daily dose will be about 1 mg or more. Typically, an effective maximum daily dose will
not exceed about 600 mg.
Combination Therapy
SAM Classic free base, or a pharmaceutical salt thereof (preferably the hemi-
succinate salt of SAM Classic free base, more preferably SAM Classic Hydrate), may be
used in combination with other drugs that are used in the treatment of the diseases or
conditions for which the present salts are useful, e.g., treatment of obesity and/or type 2
diabetes. Such other drug(s) may be administered, by a route and in an amount commonly
used therefore, contemporaneously or sequentially with the free base of SAM Classic (or
salt thereof). When SAM Classic free base, or a salt thereof, is used contemporaneously
with one or more other drugs, a pharmaceutical unit dosage form containing such other
drugs in addition to SAM Classic free base (or salt thereof) may be preferred.
Accordingly, the pharmaceutical compositions of the present invention include those that
also contain one or more other active ingredients, in addition to SAM Classic free base (or
salt thereof).
A preferred combination therapy for the treatment of obesity is the use of SAM
Classic Hydrate in combination with Meridia® (sibutramine or active metabolites of
sibutramine, e.g., desmethyl sibutramine and di-desmethyl sibutramine, preferably with
sibutramine hydrochloride mono-hydrate) or with Xenical® (orlistat).
WE CLAIM:
1. A process for preparing crystalline variable hydrate of (S) - ( 3 -pyridine
carboxamide, 6-[4-[2-[[3-(9H- carbazol - 4 - yloxy )-2-hydroxypropyl J
amino] - 2 - methylpropyl ] phenoxy ]) - hemi-succinate salt comprising;
a. Combining crystalline ethanol solvate of SAM classic with deionized
water and stirring the resulting slurry at ambient temperature for 25 hours;
and
b. Filtering the slurry under nitrogen pressure; and
c. Rinsing the filter cake with water; and
d. Drying the filter cake at ambient temperature under the purge of nitrogen
that has been bubbled through a saturated solution of potassium acetate in
water; and
e. Drying the filter cake to obtain a crystalline variable salt;
wherein the water and ethanol content of said hydrate is between 6 to 11 % and <
1% by weight respectively when measured at 22±5°C and between 10-80%
relative humidity; having a X-ray diffraction pattern which comprises the
following peaks: 7.6 ±0.1, 8.0±0.1, 8.8 ±0.1, 11.0+0.1, 13.1±0.1, 13.3±0.1, 13.8
±0.1, 15.3+0.1 and 15.5+0.1° in 29; when the pattern is obtained at 20-25°C and
25-30% relative humidity (RH) using a copper radiation source (CuKa; X=
1.54056 A).
2. The process as claimed in claim 1, wherein the water content is between 7.5 and
11% by weight.
3. The process as claimed in claim 1, wherein a solid-state ljC nuclear magnetic
resonance spectrum of the said product which comprises peaks at the following
chemical shifts: 59.8 ± 0.1, 111.4 ± 0.1 and 151.4 ± 0.1 ppm when the hydrate has
been equilibrated at 33% R.H. prior to data collection.
4. The process as claimed in claim 3, wherein said hydrate having a solid-state 13C
nuclear magnetic resonance spectrum which further comprises peaks at the
following chemical shifts: 99.2 ± 0.1, 102.4 ± 0.1, 134.9 ± 0.1, 146.9 ± 0.1 and
149.2 ±0.1 ppm.
5. The process as claimed in any one of the claims 1-4, wherein the amount of
chemical impurities present is < 2% by weight.
6. The process for preparing a non collapsing crystalline variable hydrate
substantially as herein described with reference to the given examples and
accompanying drawing.

A PROCESS FOR PREPARING A CRYSTALLINE VARIABLE HYDRATE OF (S) -
( 3 -PYRIDINE CARBOXAMIDE, 6 - [ 4 - [ 2 - [ [3- ( 9 H - CARBAZOL - 4 -
YLOXY )-2-HYDROXYPROPYL ] AMINO] - 2 - METHYLPROPYL ] PHENOXY ]
) - HEMI-SUCCINATE SALT
The present invention relates to a process for preparing a crystalline variable hydrate of
(S)-(3-pyridinecarboxamide, 6-[4-[2-[[3-(9H-carbazol-4-yloxy)-2-hydroxypropyI]
amino]-2-methylpropyl] phenoxy])-hemi-succinate.