Why Crystals Matter to the Real World

Transcription

1 Why Crystals Matter to the Real World

2 Outline of lecture What is a crystal? Crystals are everywhere in Nature Applications of crystals: drug products Applications of crystals: porous materials

3 First some ancient history years ago D- and L- quartz: chiral crystals Pasteur s spontaneous resolution experiment in 1848 started the field of stereochemistry The original crystal, named after the Greek word κρύσταλλος(krystallos) meaning clear ice (thought at time to be a hard version of ice)

4 The basics: molecules form crystals solution supersaturated solution crystal When solutions are brought to a state of supersaturation in a controlled fashion, normally by cooling or evaporation, the vast majority of substances form one or more crystalline solids. Crystal =a regular repeating array of molecules or ions that extends in 3D.

5 The basics: amorphous solids also exist Amorphous solid: No long-range repeating pattern of molecules or ions. Typically prepared by fast cooling, anti-solvent and other methods that do not give crystals time to form. Always less stable than crystalline solids

6 Outline of lecture What is a crystal? Crystals are everywhere in Nature Applications of crystals: drug products Applications of crystals: porous materials

7 Peacock butterfly thanks to Kieran Hodnett of SSPC

8 Peacock butterfly magnified thanks to Kieran Hodnett of SSPC

9 Further magnified wing thanks to Kieran Hodnett of SSPC

10 Butterfly wing magnified 50x thanks to Kieran Hodnett of SSPC

11 Butterfly wing scales magnified 200x thanks to Kieran Hodnett of SSPC

12 Butterfly wing scales magnified 1000x. thanks to Kieran Hodnett of SSPC

13 Butterfly wing scales magnified 5000x. thanks to Kieran Hodnett of SSPC

14 Material = nanocrystals of chitin = the same substance that forms exoskeletons of shellfish and beetles thanks to Kieran Hodnett of SSPC

15 Magnified Kidney Stone thanks to Kieran Hodnett of SSPC

16 Material = nanocrystals of calcium phosphate = the same substance that forms bones and teeth thanks to Kieran Hodnett of SSPC

17 Crystals of cocoa butter in chocolate Active ingredient = theobromine thanks to Kieran Hodnett of SSPC

18 Dental plaque = crystals of calcium phosphate + biomolecules thanks to Kieran Hodnett of SSPC

19 thanks to Kieran Hodnett of SSPC

20 Pharmaceutical Science Crystal forms are preferred for oral delivery of APIs Purity Processability Patentability Physicochemical properties Stability Reproducibility Cost of delivery i.e. material properties make the medicine BUT: 85% of New Chemical Entities (NCEs) exhibit low solubility

21 Outline of lecture What is a crystal? Crystals are everywhere in Nature Applications of crystals: pharmaceuticals Applications of crystals: porous materials

22 Application 1 Early Drug Discovery and Development Pre-formulation Molecules Medicinal Chemistry Materials Drug Substance(s) Formulation Medicines Drug Product le API Active Pharmaceutical Ingredient Excipients 21

23 What is a Cocrystal? solids that are crystalline single phase materials composed of two or more different molecular and/or ionic compounds generally in a stoichiometric ratio 1 Molecular Cocrystals Two or more different neutral coformers Typically held together by halogen or H-bonds Ionic Cocrystals Three or more components with at least one salt plus a nonvolatile neutral molecule (or an additional salt) Typically sustained by chargeassisted H-bonds or coordination bonds Atimupala, S., Cryst. Growth Des., 2012, 12, 2047

24 Ionic cocrystal = 3 variables = diversity Can use same components as molecular cocrystals, i.e. GRAS Introduces salt option as part of complex, i.e. lithium chloride + L-proline LiX.aM.bS Why Ionic Cocrystals Employs stronger (robust) interactions, more reliable square grid diamondoid abw zeolite 23 Ong, T. et al., J.Am.Chem.Soc., 2011, 133, 9224

25 Ionic CocrystalsChronology Rome de l Isle crystallizes NaCl with octahedron morphology (instead of cubic) in presence of urine Discovery of a compound formed by sodium chloride and glucose Publication of sodium chloride, urea and water (1:1:1) 1991 Structure report of sodium chloride, glucose and water (2:1:1) NaCl NaCl Urea H 2 O Rome de L Isle, Crystallographie, 2nd ed. Paris, 1783, 1, Kobell, F, V. J. für Prakt. Chemie., 1843, 28,

26 Other motivation to study crystal forms of drug substances The $30 billion patent: ranitidine HCl(Zantac ) form II FORM 1 Crystal forms of drug substances are preferred for oral delivery = highly valuable materials for drug products Form 2 is: Novel Not obvious Has utility FORM 2

27 Chem. Commun, 2016, 52, , DOI: /C5CC08216A

28 Outline of lecture What is a crystal? Crystals are everywhere in Nature Applications of crystals: pharmaceuticals Applications of crystals: porous materials

29 The Porous Materials Universe Hybrid Ultramicroporous Materials 28

30 Metal-Organic Materials MOMs Also known as MOFs, PCPs, PCNs, [Zn(4,4 -bipy) 2 (H 2 O) 2 SiF 6 ] n Gable, R. W.; Hoskins, B. F.; Robson, R. A. JCS Chem. Commun. 1990,1677. METALor Molecular Building Block, MBB, makes three or more connections: is a node ORGANICmolecule makes only two connections: is a linker Many combinations = many structures (est. 20,000) R.A. Robson Nanoscale cavity = a MATERIAL

31 The first extra-large surface area materials ca. 1900m 2 /g ca m 2 /g [Cu 3 (BTC) 2 (H 2 O) 3 ] n, HKUST-1 (tbo) Chui, S.S.Y.; Lo, S.M.F.; Charmant, J.P.H.; Orpen, A.G.; Williams, I.D., Science,1999, 283, [(Zn 4 O)(bdc) 3 ] n, MOF-5 (pcu) Li, H.; Eddaoudi, M.; O'Keeffe, M.; Yaghi, O. M., Nature, 1999, 402,

32 13600m m 2 Why is empty space useful? Things can go in (trapped) and out (controlled release) Zeolites such as zeolite A, zeolite XY (alongside) and rho-zeolite are made industrially (millions of tons/year). They are widely used in gas purification, water softening, drug delivery and petroleum refining. MOMs exhibit up to 7000m 2 /g surface area Existing materials are generally limited to 1000 m 2 /g