Powder X-Ray Diffraction and its Applications in Pharmaceutical Industry

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1 Powder X-Ray Diffraction and its Applications in Pharmaceutical Industry Shawn Yin, Ph. D. Drug Product Science & Technology Research & Development Bristol-Myers Squibb Co. USA NYU XRD Workshop, New York University June,

2 Outline Pharmaceutical substances PXRD & other physical characterization technologies When and where to use PXRD in pharmaceutical industry PXRD Pharmaceutical Applications

3 Bulk Pharmaceutical Substances Pharmaceutical solid substances: API or API like materials (intermediates), excipients, mixtures (granules, tablets), etc. Physical States: Crystalline, amorphous, their mixtures (semicrystalline) and liquid crystal Properties: Stability, solubility, crystallinity, hygroscopicity, dissolution rate, bioavailability, powder properties, etc.

4 Crystalline and Amorphous Solids Crystalline: Solid having a regularly repeating arrangement of the chemical entity Examples: table salt, graphite, lactose monohydrate, Aripiprazole API etc. Amorphous: Solid that lacks long-range order of the chemical entity Examples: window glass, cotton candy, HPMC and other cellulous containing materials, Amorphous Warfarin Sodium API etc.

5 Polymorphism Polymorphism is the propensity of a substance to crystallize into more than one crystal structure As expected, different polymorphic forms will have different properties Example: BMS (Aripiprazole) S. Yin, 9th Annual Polymorphism & Crystallization Scientific Forum, Phila, PA, 2010

6 Pseudo-polymorphism S. Yin, 9th Annual Polymorphism & Crystallization Scientific Forum, Phila, PA, 2010 Polymorphic solvates/ Solvatomorp hism : a transformation to another crystal structure takes place upon desolvation and resolvation; Pseudopolymorphism : the crystalline structure is maintained upon desolvation and resolvation Chemical composition is not the same Example: BMS (Aripiprazole)

7 Pharmaceutical Polymorphism (by Regulatory Agencies) Polymorphism refers to the occurrence of different crystalline forms of the same drug substance Polymorphism (in this commentary) is defined as in the International Conference on Harmonization (ICH) Guideline Q6A (2), to include solvation products and amorphous forms. lymorphism.htm

8 Viewing Materials Through Different Lenses Bulk (Macro-) Level: one batch of Abilify API material size range: larger than 100 microns viewing by biologic lens - naked eyes Particulate (Meso-) Level: crystals of NaCl size range: sub microns to microns viewing through mechanic lens - microscopes Atomic/Molecular (Micro-) Level: molecules of Aripiprazole size range: less than 100Å physically not visible by common means (but indirectly by mathematic lens - single crystal structure through Fourier Transformation)

9 Common Technologies for Solid-State Characterization Diffraction (single crystal/powder) X-ray, neutron, electron Thermal analysis DSC (DTA), TGA, TSC, TMA, DMA, etc. Spectroscopic IR, NIR, Raman, SSNMR, etc. Micromeritics Surface Area, Particle Size, igc, Vapor Sorption, etc. Microscopy Optical, SEM, TEM, STM, AFM, etc. Combinations Hot-stage microscopy, VT-PXRD/DSC, TG-IR/MS etc. Multi-disciplinary approaches

10 Powder X-ray Diffraction incident beam diffracted beam q q q d Bragg s Law: 2 d sin q = n q = incident angle, = wavelength, d = spacing of crystal planes

11 2 Dimension Diffraction Cones Courtesy of Bruker-AXS

12 Powder X-ray Diffraction (from diffraction cones to PXRD pattern) Peak position: determined by the size of unit cell of crystal structure Peak intensity: determined by the contents of the unit cell

13 Single Crystal X-ray Diffraction & Crystal Structures Measure observed intensity I (hkl) K F 2 (hkl) where K = scale factor and other set-up coefficients Extract structure factor F(hkl) obs = f N exp[2 i(hx N + ky N + lz N )] Perform reverse Fourier transformation (xyz) = (1/V c ) F(hkl) exp[-2 i(hx N + ky N + lz N )] Extract atomic coordinates x,y,z 3D reciprocal space to 3D direct space for single crystal work

14 Simulating Powder XRD Patterns from Crystal Structures Solve (or model) crystal structure: Derive atomic coordinates (xyz) (or from Cambridge Database) Structure factor: F(hkl) cal = f N exp[2 i(hx N + ky N + lz N )] or F(hkl) obs 3D calculated intensities (hkl): I (hkl) K F 2 (hkl) 1D calculated intensities (2q): I (2q) = K L(q) I (hkl) A(q) Bragg s Law: 2 d sin q = n where I(q) is associated to I(hkl) by the relationships of (hkl), d and then Bragg s Law 3D direct space to 1D reciprocal space for PXRD Squeezing 3D into 1D (single crystal vs. powder diffraction data) 14

15 Examples: Polymorphism & Pseudo Polymorphism Intensity(Counts) Observed N-6 Simulated N-6 Observed N-5 Simulated N-5 Observed N-4 Simulated N-4 Observed N-3 (via VT-PXRD) Simulated N-3 Observed N-2 Simulated N Observed N-1 Simulated N-1 Observed H-0 Simulated H Theta( ) S. Yin, 9th Annual Polymorphism & Crystallization Scientific Forum, Phila, PA, 2010

16 Common Pharmaceutical Applications of PXRD PXRD is a primary, non-destructive, crystal form identification technique, for API and drug product: Qualitative (most of time) Quantitative form composition determination Pure form or mixture of forms Large or small sample quantity Simple or no sample preparation Crystallinity of solid materials (crystalline vs. amorphous) Average crystallite size analysis (for crystallite size in the sub-micron to nanometer ranges) Solving crystal structures from powder diffraction data Powder pattern indexing for form homogeneity Confirming reference standards for secondary techniques (FT-IR/NIR/Raman, SSNMR, DSC, etc.)

17 Drug Discovery & Development Stages - when & where to use PXRD Discovery to early exploratory development Crystalline or amorphous Structure ID for crystalline materials (usually requires crystal structure) Early exploratory development up to First in Human/Phase I Polymorphic/salt form screening (HTC and/or manual) and final form selection for development Comprehensive physical characterization for critical and process relevant forms Data for IND filling/form patent Late Stage/Phase II/III Assisting process and formulation development activities: thermodynamics and kinetics of relevant forms; API scale-up; API & DP LTSS; API form ID & crystallinity in DP; etc. Method development for technology transfer Data for CMC section of NDA filling Post-approval/Life cycle management New formulation development Trouble-shooting for manufacturing issues

18 Intensity(Counts) API Drying Process Control Simulated N Observed LTSS Batch 0 Simulated H Theta( ) S. Yin et. al., Opinion in Drug Discovery & Development, 11(6), (2008)

19 API Drying Process Control a H2 O s RH a H 2Ov Slurry a H2 O l At equilibrium: a v = a l = a critical A H2O A + H2O Vary H 2 O in slurry while observing form conversion Slurry approach minimizes mass transfer concerns Checked form by slurry PXRD: H-1 -> N-3 favored for RH < 2%; N-3 -> H-1 favored for RH > 9% On scale process drying studies suggested the same RH range for conversions between H-1/N-3 Preliminary results indicate ~4.5%RH is thermodynamic limit (estimated with slurry exp., KF data and VLE calculator)

20 Dewpoint ( C) API Drying Process Control Thermodynamically Safe Zone Tdp = *Tcake Temperature ( C) S. Yin et. al., Opinion in Drug Discovery & Development, 11(6), (2008)

21 Intensity(Counts) API Drying Process Control 7500 Simulated N-3 LTSS Batch # LTSS Batch #6 LTSS Batch #5 LTSS Batch #4 LTSS Batch #3 LTSS Batch #2 LTSS Batch #1b LTSS Batch #1 Simulated H Theta( ) S. Yin et. al., Opinion in Drug Discovery & Development, 11(6), (2008)

22 Thermal Study - Variable Temperature PXRD - Problems Sample displacement shift due to sample movement Cell expansion (contraction) due to temperature change Possible phase transition(s) Possible degradation at elevated temperatures

23 Intensity(Counts) Simulated vs. Observed PXRD Patterns - Refine the simulated pattern Simulated -50C 1000 Observed 500 Simulated - refined at 25C Theta( ) Theta( ) S. Yin et. al., American Pharmaceutical Review, Vol.8, Issue 2, p56-62, (2005) hybrid

24 Intensity(Counts) Thermal Study - Variable Temperature PXRD Simulated Solvent-Free Form I 100C 1000 Observed 100C 500 Observed RT 0 "Hydrid" Hydrate RT Theta( ) S. Yin et. al., American Pharmaceutical Review, Vol.8, Issue 2, p56-62, (2005)

25 Weight (%) Heat Flow (W/g) Deriv. Weight (%/ C) Heat Flow (W/g) Thermal Study - Variable Temperature PXRD - Thermal Analysis Confirmation C C 4.621J/g Exo Up Temperature ( C) Universal V3.6C TA Instruments Exo Up Temperature ( C) Universal V2.5H TA Instruments S. Yin et. al., American Pharmaceutical Review, Vol.8, Issue 2, p56-62, (2005)

26 Intensity(Counts) Thermal Study - Variable Temperature PXRD 2500 Simulated Solvent-Free Form II RT 2000 Observed 25C (cooled) 1500 Observed 175C 1000 Simulated Solvent-Free Form I 100C Observed 100C T heta( ) S. Yin et. al., American Pharmaceutical Review, Vol.8, Issue 2, p56-62, (2005)

27 What are the API Forms in Drug Product? 27

28 API Crystal Form in Drug Product - PXRD Patterns Intensity(Counts) ] Blue - Simulated HCl Salt Hydrate I > Anatase, syn - TiO Brown - Simulated HCl Salt Hydrate II Red Red mg tablet mg tablet Green - TiO2 150 TiO Talc Theta( ) S. Yin, 9th Annual Polymorphism & Crystallization Scientific Forum, Phila, PA, 2010

29 API Crystal Form in Drug Product - NIR Spectrum HCl salt hydrate II Talc S. Yin, 9th Annual Polymorphism & Crystallization Scientific Forum, Phila, PA, 2010

30 API Crystal Form in Drug Product - NIR Spectrum HCl salt hydrate II HCl salt hydrate I S. Yin, 9th Annual Polymorphism & Crystallization Scientific Forum, Phila, PA, 2010

31 Spray Drying Pharmaceutical Ingredients 31

32 Intensity(Counts) PXRD Patterns of Spray Dried Samples BMS :10 Drug:Pluronic :50 Drug:Pluronic :80 Drug:Pluronic Pluronic F Theta( ) Both crystalline drug and Pluronic are found in the SDD samples by PXRD The metastable API form was formed in the system * S. Yin et. al. J. Pharm. Sci., 2005, Vol. 94, No. 7,

33 DSC Thermograms of Spray Dried Samples Both crystalline drug and Pluronic are found in the SDD samples by DSC * S. Yin et. al. J. Pharm. Sci., 2005, Vol. 94, No. 7,

34 Intensity(Counts) PXRD Patterns of SDD Samples [34094.SD] <2T(0)=-0.054> [34095.SD] <2T(0)=-0.052> [33531.SD] FORM N :80 SP :50 SP :10 SP 0 pure drug T heta( ) S. Yin et. al. J. Pharm. Sci., 2005, Vol. 94, No. 7,

35 Scherrer s Equation = (K )/( cosq) - crystallite dimension K shape factor (~0.9) ; - the wavelength; - line broadening due to the effect of small crystallites Base on Scherrer s equation, the crystallite size reduction of crystalline drug (assuming that all the peak broadening is caused by crystallite size reduction): Pure drug (averaged above 5 m) > Pluronic SP (averaged ~ 60 nm) 35

36 Time Evolution of PXRD x10^ Theta( ) Min a 50:50 drug:pluronic F127 film cast from acetone * S. Yin et. al. J. Pharm. Sci., 2005, Vol. 94, No. 7,

37 Proposed Model for Nano-sized Crystalline Drug * S. Yin et. al. J. Pharm. Sci., 2005, Vol. 94, No. 7,

38 Summary PXRD is a primary and most common technique for API form/phase studies PXRD plays a very important role in all stages of pharmaceutical research and development However, the multi-disciplinary/technique approach should be used as the best practice 38