Modern Methods for the Separation of Enantiomers - from Kilos to Tons

Modern Methods for the Separation of Enantiomers - from Kilos to Tons -

Organic Process Research and Development February 2014 Chirality in Drug Pipeline

- Over 80% of drug candidates contain at least one chiral center

- Increasingly complex molecules, requiring more advanced production methodologies

-Three General Strategies -Chiral Pool -Asymmetric Synthesis -Resolution

Challenge

• Is there an optimal approach to problem?

• No – each stage is driven by different imperatives, therefore choices are also different

Pre-Clinical

• Short-term Focus –Speed is key –Cost less of an issue

• Pragmatic approach –Produce racemate then separate –Less effort on asymmetric synthesis, chiral pool (only if quick and easy)

Clinical

• Long-term focused – Scalability, cost, efficiency, robustness

• “Tool Box” Approach – Cannot assume that any approach is invalid – Test all, then run economic feasibility

Chiral Separation

• Used at all stages – Classical Resolution – Chiral Chromatography

Chiral Separation

• Used at all stages – Classical Resolution – Chiral Chromatography

• Enabling Chiral Separations – Developing efficient methods – Small-scale runs (> 100kg) – Technology Transfer for commercial CHIRAL TECHNOLOGIES INC.

West Chester, PA. 23,000 sq ft Labs & Offices

Perceptions of Chromatography

• Chromatography is considered to be:

– Last Resort – Temporary Solution – Inelegant – Difficult to Use

Reality of Modern Chromatography

• Chromatography is;

– Cost effective – Reliable – Scalable

Scalable Technology

Methods are developed on analytical columns

Photo courtesy of AMPAC Scalable Technology

Ampac Fine Chemicals

Photo courtesy of AMPAC Chiral Chromatography Method Development

• Screen compound – Chiral Stationary Phase (CSP) – Mobile Phase • Determine Optimum Combination • Perform Loading Study • Run Stability Tests • Productivity = kg enantiomer/kg CSP/day Key Points to Consider

• Solubility characteristics • Stability (chemical and stereo) • Presence of other impurities • API or intermediate • Ability to racemize non-target enantiomer Chiral Stationary Phase

OR Amylose-based OR O Cellulose-based O RO O OR n RO O OR n

CSP Nature -R CSP Nature -R

CH3 H CHIRALPAK IA Immobilized N CHIRALPAK IB Immobilized O CH3

H CHIRALPAK ID Immobilized N Cl O Cl H CHIRALPAK IC Immobilized N

CHIRALPAK IE Immobilized O Cl

H N CH CHIRALPAK IF Immobilized 3 O Cl Screening Study a-Methyl-a-Phenylsuccinimide

O O N mAU H 120 Multiple separation opportunities Also separates with conventional 100 THF/Hexane solvents. Note, zero THF selectivity 80

60 CHCl 3 40 EtOAc MTBE CHIRALPAK IA, 250 x 4.6 mm 20 Flow rate 1 ml/min ACN:IPA 85:15 UV detection 254 nm 0

0 5 10 15 20 25 30 35 min Dichloromethane/THF 70:30 (Column 25 x 0.46 cm, 5 µm 5CSP) cm, 0.46x 25(Column F = 1 mL/min, 25 mL/min, = 1F Absorbance (AU) Chiral Separation of EMD of SeparationChiral 0.0 0.1 0.2 0.3 0.4 0.5

° C Analytical Analytical injection

Retention Time(min) 3

4 3.9 5

6 -

53986 Solubility in mobile phase: 45 g/L 7

H N

PrecursorforCa

8.3 9

EMD

10 N H - -

53986 sensitizing drug sensitizing S

Dichloromethane/THF 70:30 (Column 25 x 0.46 cm, 5 µm 5CSP) cm, 0.46x 25(Column F = 1 mL/min, 25 mL/min, = 1F Absorbance (AU) 0.0 0.1 0.2 0.3 0.4 0.5 Loading Study forStudy Loading EMD

° C

loading 1

12mg 16mg

20mg 2 8mg 4mg

Retention Time(min) 3

4 3.9 5

53986 6

Solubility in mobile phase: 45 g/L 7

8.3 9

Dichloromethane/THF 70:30 (Column 25 x 0.46 cm, 5 µm 5CSP) cm, 0.46x 25(Column F = 1 mL/min, 25 mL/min, = 1F Absorbance (AU) 0.0 0.1 0.2 0.3 0.4 0.5 Loading Study forStudy Loading EMD

° C

loading 1

12mg 16mg

20mg 2 8mg 4mg

Retention Time(min) 3

4 3.9 5

53986 6

Solubility in mobile phase: 45 g/L 7

8.3 9

Dichloromethane/THF 70:30 (Column 25 x 0.46 cm, 5 µm 5CSP) cm, 0.46x 25(Column F = 1 mL/min, 25 mL/min, = 1F Absorbance (AU) 0.0 0.1 0.2 0.3 0.4 0.5 Loading Study forStudy Loading EMD

° C

loading 1

12mg 16mg

20mg 2 8mg 4mg

Retention Time(min) 3

4 3.9 5

53986 6

Solubility in mobile phase: 45 g/L 7

8.3 9

Dichloromethane/THF 70:30 (Column 25 x 0.46 cm, 5 µm 5CSP) cm, 0.46x 25(Column F = 1 mL/min, 25 mL/min, = 1F Absorbance (AU) 0.0 0.1 0.2 0.3 0.4 0.5 Loading Study forStudy Loading EMD

° C

loading 1

12mg 16mg

20mg 2 8mg 4mg

Retention Time(min) 3

4 3.9 5

53986 6

Solubility in mobile phase: 45 g/L 7

8.3 9

Dichloromethane/THF 70:30 (Column 25 x 0.46 cm, 5 µm 5CSP) cm, 0.46x 25(Column F = 1 mL/min, 25 mL/min, = 1F Absorbance (AU) 0.0 0.1 0.2 0.3 0.4 0.5 Loading Study forStudy Loading EMD

° C

loading 1

12mg 16mg

20mg 2 8mg 4mg

Retention Time(min) 3

4 3.9 5

53986 6

2.8kg enantiomer/kg CSP/day Solubility in mobile phase: 45 g/L 7

Estimated productivity: Estimated

8.3 9

Preparative chromatography

HPLC (batch) SMB (continuous) Glutethimide

Productivity: > 11 kg enantiomer/kg CSP/day

Productivity demonstrated under SMB conditions 54 mg 42 mg Ethyl acetate 100% 36 mg 30 mg F = 1 mL/min, 25°C 15 mg (Column 25 x 0.46 cm, 20 µm CSP)

0 1 2 3 4 5 6 7 8 9 10 11 min Solubility in mobile phase: 300 g/L Case Studies

• Two Clinical Development Projects

1) Continuous Enantio-Enrichment

2) Stage-Appropriate Technology

1) Continuous Enantio-Enrichment

• Biogen Idec Alzheimer’s Drug

- BIIB042 - Two chiral centers - Continuous process developed BIIB042 Structure

* Initial Drug Discovery Approach

O O O MeO MeO MeO Mannich Triflation NH CHO + + OH OTf 70-80% 90% OH F N N BIM-651 F F BIM 702 O O O

MeO HO OH Chiral Suzuki Hydrolysis separation

CF3 15-18% 60-80% CF3 100% CF3 N N N

F F F BIO-20377 BIIB042

The Mannich reaction established the framework for BIIB042 in the first step producing BIM-702, and chiral chromatography was employed to separate the four stereoisomers. Formation of First Chiral Center

CO2Me CO2Me

CO2Me diastereomeric salts and enzymatic approaches N toluene, 110 oC were not successful H OH OH + RX Heptane 70-75% OH OHC SMB, 100% N * N F F F BIM-702 BIM-752 Chiral SMB Approach

• Screened against matrix of chiral stationary phases/solvents - Best method; AD CSP with Hexane/IPA

• Determined optimum process parameters - Yield, %ee

Continuous SMB Process

Racemic BIM702 90 kg

Chiral SMB Continuous SMB Process

Racemic BIM702 90 kg

Chiral SMB

BIM752 >99.5%ee Continuous SMB Process

Racemic BIM702 90 kg

Chiral SMB

Non-Target Enantiomer BIM752 >99.5%ee Continuous SMB Process

Racemic BIM702 90 kg

Racemization

Chiral SMB

Non-Target Enantiomer BIM752 >99.5%ee Continuous SMB Process

Racemic BIM702 90 kg

Racemization

Chiral SMB

Non-Target Enantiomer BIM752 >99.5%ee Lab Scale SMB Second Chiral Center

CO 2 M e CO 2 H CO 2 H

So d i um Ru ( B I NA P) , H2 * tr i me th y ls i lo n a t e 4 0 a tm CF 3 CF 3 e na n t i o s el e ct i v e * CF 3 * N N N * F F F B I M- 75 7 B I M- 79 5 B I IB 04 2

>95% ee via catalytic hydrogenation (Ru) 2) Stage-Appropriate Technology

• Development of Armodafinil

• Cephalon (Teva)

Stage-Appropriate Technology

• Modafinil (Provigil) O O S – Approved for treatment of apnea, NH2 narcolepsy, shift work disorder – Racemic API

• Armodafinil (Nuvigil) O O – (R)-Enantiomer S NH2 – Second generation therapy

Pre-Clinical Phase

aq. NaOH Na2CO3, Me2SO4 aq. HCl, acetone aq. acetone

NH3, MeOH

DMSAM Modafinic Acid Modafinil

- Modafinic Acid was the best candidate for classical resolution

- Easily converted to R-Modafinil Pre-Clinical Phase

• 85 kgs prepared via crystallization - ~98% ee - Conversion to R-Modafinil - Non-ideal system due to ● Product degradation ● Cost inputs ● High labor component

Clinical Phase

• Chiral HPLC/SMB study on Modafinil – Screened CSPs – HPLC and SMB methods developed

• 60kg of Phase I material produced – Single column HPLC – >99.0%ee

O O O O S S HPLC NH NH2 2 Clinical Phase

• 550kg Phase II/III material produced - Chiral SMB - Optical purity >99.2%ee - Chemical purity >99.7%

• Over 10 MT of racemate processed via SMB - Novasep operation - Process ran on 300mm and 450mm systems - Stabile, robust process Commercial Launch

• Asymmetric Oxidation Results - 75% isolated yield - >99.5% optical purity

• Significantly longer development than chromatography

• Favorable economics

• Launch of Armodafinil was accelerated due to stage- appropriate technologies Development of Armodafinil

• Three different methods employed

• Pre-Clinical – Classical Resolution • Clinical Trials – Chiral SMB • Commercial Launch – Asymmetric Synthesis

• Result – Speed to Market Conclusions

• Chiral Chromatography can offer advantages – Effective from mgs to MTs – Predictable scale factors – Ability to “dial in” desired %ee

Acknowledgements Thank You Partners

• Biogen Idec

• Teva (Cephalon)

• Novasep move easily …

move reliably …

move quickly …

move ahead

Chiral Technologies