Organic Process Research & Development
ARTICLE
Dynamic vapor sorption data were collected at 25 °C using
a VTI SGA 100 symmetrical vapor sorption analyzer. Relative
humidity was varied in increments of 5%, starting at 5%
relative humidity, increasing to 95% relative humidity, and
then undergoing a drying cycle back to 5% relative humidity.
Equilibrium criteria were set at 0.01% weight change in 1 min
with a maximum equilibrium time of 180 min. Approximately
1À5 mg of sample was used.
’ ACKNOWLEDGMENT
The authors thank Matthew Noestheden and Darren Reid for
the supporting forced degradation data and Yang Xu for the
supporting PK data for these investigations.
’ NOTATION
MeOH = methanol; EtOH = ethanol; THF = tetrahydrofuran;
MeCN = acetonitrile; IPA = isopropanol; HOAc = acetic acid;
DMF = dimethylformamide; IPAc = isopropyl acetate
Karl Fischer titrations were performed using a Mettler Toldeo
C20 Coulometric KF titrator filled with Aquastar CombiCoulo-
mat Methanol Solution. Approximately 20À30 mg of sample was
used for analysis.
HPLC for solubility measurements was run using an Agilent
Series 1100 having a Phenomenex Luna C18 column (30 Â
4.60 mm, 3 μm). Analyses were run with a gradient method using
98% water 2% acetonitrile (mobile phase A) and 98% acetonitrile
2% water (mobile phase B) with a gradient going from 10% to
95% B at a flow rate of 1 mL/min and a total run time of 5 min.
UV detection was run at a wavelength of 254 nm.
HPLC for stability samples was run using an Agilent Series
1100 having a Bonus RP column (3 mm  150 mm, 3.5 μm).
Analyses were run with a gradient method using 90% water 10%
methanol with 0.05% trifluoroacetic acid (mobile phase A) and
40% acetonitrile 60% methanol with 0.05% trifluoroacetic acid
(mobile phase B) with a gradient going from 10% to 85% B at a
flow rate of 0.6 mL/min and a total run time of 57 min. UV
detection was run at a wavelength of 324 nm.
Polymorph and Salt Screening. Recrystallization experi-
ments included evaporation, slurries, antisolvent addition, and
heating experiments. Evaporation experiments were conducted
by dissolving approximately 5À10 mg of the API in a given
solvent, filtering the solution with a 0.45 μm PTFE filter into a
vial, then either leaving the vial uncovered or covering the vial
with pin-holed Parafilm to dry. Slurry experiments were per-
formed by saturating a giving solvent with API, such that excess
solid was in constant contact with solution. The sample was then
agitated on a slurry wheel at room temperature for approximately
1 week. Antisolvent addition experiments were performed by
dissolving a portion of the API in 1 mL of solvent followed by
addition of 25 mL of antisolvent and then cooling the solution in a
refrigerator. Solids from slurry and antisolvant addition experiments
were isolated via suction filtration and allowed to air-dry.
Solubility Measurements. Solubility measurements (n = 1)
were conducted by saturating a given solvent system with API at a
given temperature, and agitating the mixture for 24 h. The sus-
pension was then filtered using a PTFE (0.45 μm) filter. The
resulting solid phase was examined via XRPD, while the resulting
solution was analyzed for drug concentration via HPLC. For
each experiment, no phase change or salt disproportionation
was observed.
’ REFERENCES
(1) Cee, V. J.; Frohn, M.; Lanman, B. A.; Golden, J.; Muller, K.;
Neira, S.; Pickrell, A.; Arnett, H.; Buys, J.; Gore, A.; Fiorino, M.; Horner,
M.; Itano, A.; Lee, M. R.; McElvain, M.; Middleton, S.; Schrag, M.;
Rivenzon-Segal, D.; Vargas, H. M.; Xu, H.; Xu, Y.; Zhang, X.; Siu, J.;
Wong, M.; Burli, R. W. ACS Med. Chem. Lett. 2011, 2 (2), 107–112.
(2) Rosen, H.; Gonzalez-Cabrera, P. J.; Sanna, M. G.; Brown, S.
Annu. Rev. Biochem. 2009, 78, 743–768.
(3) Takabe, K.; Paugh, S. W.; Milstien, S.; Spiegel, S. Pharmacol. Rev.
2008, 60, 181–195.
(4) Salvadori, M.; Budde, K.; Charpentier, B.; Klempnauer, J.;
Nashan, B.; Pallardo, L. M.; Eris, J.; Schena, F. P.; Eisenberger, U.;
Rostaing, L.; Hmissi, A.; Aradhye, S. Am. J. Transplant. 2006, 6,
2912–2921.
(5) Kappos, L.; Radue, E. W.; O’Connor, P.; Polman, C.; Hohlfeld,
R.; Calabresi, P.; Selmaj, K.; Agoropoulou, C.; Leyk, M.; Zhang-
Auberson, L.; Burtin, P. New Engl. J. Med. 2010, 362, 387–401.
(6) Cohen, J. A.; Barkhof, F.; Comi, G.; Hartung, H. P.; Khatri, B. O.;
Montalban, X.; Pelletier, J.; Capra, R.; Gallo, P.; Izquierdo, G.; Tiel-Wilek,
K.; de Vera, A.; Jin, J.; Stites, T.; Wu, S.; Aradhye, S.; Kappos, L. New Engl.
J. Med. 2010, 362, 402–415.
(7) Gould, P. L. Int. J. Pharm. 1986, 33, 201–217.
(8) Bastin, R. J.; Bowker, M. J.; Slater, B. J. Org. Process. Res. Dev.
2000, 4, 427–435.
(9) Stahl, P. H., Wermuth, C. G. Handbook of Pharmaceutical Salts:
Properties, Selection and Use; Helvetica Chimica Acta: Zurich, 2002.
(10) Gross, T. D.; Schaab, K.; Ouellette, M.; Zook, S.; Reddy, J. P.;
Shurtleff, A.; Sacaan, A. I.; Aebic-Kolbah, T.; Bozigian, H. Org. Process
Res. Dev. 2007, 11, 365–377.
(11) Maurin, M. B.; Rowe, S. M.; Koval, C. A.; Hussain, M. A.
J. Pharm. Sci. 1994, 83 (10), 1418–1420.
(12) Kumar, L.; Amin, A.; Bansal, A. K. Pharm. Technol. 2008, 3 (32),
128–146.
(13) Morrison, H.; Jona, J.; Walker, S. D.; Woo, J. C. S.; Li, L.; Fang.,
J. Org. Process Res. Dev. 2011, 15 (1), 104–111.
(14) Methanol is the biproduct of hydrolysis of 2317157 with acid;
therefore, acetonitrile, tetrahydrofuran, toluene, and isopropyl acetate
were screened as solvents for the hydrolysis under these conditions.
’ ASSOCIATED CONTENT
S
Supporting Information. Further experimental data.
b
This material is available free of charge via the Internet at
’ AUTHOR INFORMATION
Corresponding Author
*Ph: 805-313-5502. Fax: 805-498-8674. E-mail: hmorriso@
amgen.com.
1343
dx.doi.org/10.1021/op200192n |Org. Process Res. Dev. 2011, 15, 1336–1343