1. Chapter 12

2. Target disease Priority for the Pharmaceutical Industry: Can the profits from marketing a new drug outweigh the cost of developing and testing that drug? Questions to be addressed: Is the disease widespread? (e.g. cardiovascular disease, ulcers, malaria) Does the disease affect the first world? (e.g. cardiovascular disease, ulcers) Are there drugs already on the market? If so, what are their advantages and disadvantages (e.g. side effects) Can one identify a market advantage for a new therapy?

3. Drug targets A) Lipids Cell membrane lipids B) Proteins Receptors Enzymes Carrier proteins Structural proteins (tubulin) C) Nucleic acids DNA RNA D) Carbohydrates Cell surface carbohydrates Antigens and recognition molecules

4. Between species: Antibacterial, antifungal and antiviral agents Identify targets which are unique to the invading pathogen Identify targets which are shared but which are significantly different in structure Within the body: Selectivity between different enzymes, receptors etc. Selectivity between receptor types and subtypes Selectivity between isozymes Organ and tissue selectivity

5. Bioassays (test systems) Tests are required in order to find lead compounds and for drug optimisation Need to be quick, easy and relevant Tests can be in vivo or in vitro A combination of tests is often used in research programs

6. Carried out on live animals or humans Measure an observed physiological effect Measure a drug’s ability to interact with its target and its ability to reach that target Can identify possible side effects Rationalization may be difficult due to the number of factors involved Transgenic animals - genetically modified animals Drug potency - concentration of drug required to produce 50% of the maximum possible effect Therapeutic ratio/index - compares the dose level of a drug required to produce a desired effect in 50% of the test sample (ED 50 ) versus the dose level that is lethal to 50% of the sample (LD 50 ) In vivo Tests

7. Tests not carried out on animals/humans Target molecules (e.g. isolated enzymes or receptors) Cells (e.g. cloned cells) Tissues (e.g. muscle tissue) Organs Micro-organisms (for antibacterial agents) More suitable for routine testing Measure the interaction of a drug with the target but not the ability of the drug to reach the target Results are easier to rationalize - less factors involved Does not demonstrate a physiological or clinical effect Does not identify possible side effects Does not identify effective prodrugs In vitro tests

8. High Throughput Screening NMR Enzyme Inhibition tests Identify competitive or non competitive inhibition Strength of inhibition measured as IC 50 IC 50 = concentration of inhibitor required to reduce enzyme activity by 50% Receptor tests Not easy to isolate membrane bound receptors Carried out on whole cells, tissue cultures, or isolated organs Affinity - strength with which compounds bind to a receptor Efficacy - measure of maximum biochemical effect resulting from binding of a compound to a receptor. Potency - concentration of an agonist required to produce 50% of the maximum possible effect. Testing drugs

10. The lead compound A compound demonstrating a property likely to be therapeutically useful The level of activity and target selectivity are not crucial Used as the starting point for drug design and development Found by design (molecular modelling or NMR) or by screening compounds (natural or synthetic) Need to identify a suitable test in order to find a lead compound Active principle - a compound that is isolated from a natural extract and which is principally responsible for the extract’s pharmacological activity. Often used as a lead compound.

11. A) The natural world B) The synthetic world C) The virtual world Plantlife (flowers, trees, bushes) Micro-organisms (bacteria, fungi) Animal life (frogs, snakes, scorpions) Biochemicals (Neurotransmitters, hormones) Marine chemistry (corals, bacteria, fish etc) Chemical synthesis (traditional) Combinatorial synthesis Computer aided drug design The lead compound

12. A) Isolation and purification solvent-solvent extraction chromatography crystallization distillation B) Structure determination elemental analysis molecular weight mass spectrometry IR spectroscopy UV spectroscopy NMR ( 1 H, 13 C, 2 D) spectroscopy X-ray crystallography Identification of the lead compound

13. Plants Lead compounds from the natural world

14. Poppy capsule Morphine Lead compounds from the natural world

15. OPIUM - MorphineOPIUM - Morphine CINCHONA BARK - QuinineCINCHONA BARK - Quinine YEW TREE - TaxolYEW TREE - Taxol Lead compounds from the natural world

16. Willow tree - salicylic acid Coca bush - cocaine Aspirin Procaine Lead compounds from the natural world

17. The beatons of pennycross Lead compounds from the natural world

18. CURE for EPILEPSY Heat a cauldron of water until warm to the touch Add a liberal sprinkling of juicy spiders Produce one pedigree dog Flavour with essence of dog turd Simmer for 20 minutes then enjoy THE BEATONS OF PENNYCROSS

19. Herbal remedies of old Majority may have worked through a placebo effect Lead compounds from the natural world Lead compounds from the natural world

20. Rain forests Lead compounds from the natural world

21. Coral and marine chemistry CURACIN Lead compounds from the natural world

22. Micro-organisms

23. Penicillin Cephalosporins Tetracyclines Streptomycin Chloramphenicol Lead compounds from the natural world Micro-organisms

24. Venoms and toxins Captopril (anti-hypertensive) Teprotide Lead compounds from the natural world

25. Venoms and toxins Lead compounds from the natural world

26. Tubocurarine (from curare) Lead compounds from the natural world Venoms and toxins

27. Atracurium (Neuromuscular blocker) Tubocurarine (from curare) Venoms and toxins Lead compounds from the natural world

28. Endogenous compounds Natural ligands for receptors Agonist Agonist Lead compounds from the natural world

29. Antagonist Antagonist Endogenous compounds Natural ligands for receptors

30. Endogenous compounds Natural substrates for enzymes Enkephalins Enkephalinase inhibitors Peptides Protease inhibitors Lead compounds from the natural world

31. Lead compounds from the synthetic world Lead compounds from the synthetic world SYNTHETIC COMPOUNDS

32. PRONTOSIL Lead compounds from the synthetic world Lead compounds from the synthetic world

33. SULFANILAMIDE Lead compounds from the synthetic world

34. TNT Lead compounds from the synthetic world

35. Rubber industry Antabuse Lead compounds from the synthetic world Lead compounds from the synthetic world

37. Organic synthesis 4.4 Lead compounds from the synthetic world

38. Automated synthetic machines Combinatorial synthesis 4.4 Lead compounds from the synthetic world

39. RESIN BEAD AMINO ACID AMINO ACIDS X PEPTIDE Combinatorial synthesis - peptide synthesis 4.4 Lead compounds from the synthetic world

40. N N YO CHR 1 R 2 RESIN BEAD Combinatorial synthesis - heterocyclic synthesis 4.4 Lead compounds from the synthetic world

41. RESIN BEADN N O R2R2 R3R3 H Combinatorial synthesis - heterocyclic synthesis 4.4 Lead compounds from the synthetic world

42. N N O O EtO O R2R2 R3R3 R4R4 R5R5 RESIN BEAD Combinatorial synthesis - heterocyclic synthesis 4.4 Lead compounds from the synthetic world

43. N N N NHNNHN O R2R2 R3R3 R4R4 R5R5 RESIN BEAD Combinatorial synthesis - heterocyclic synthesis 4.4 Lead compounds from the synthetic world

44. N N YN O R2R2 R3R3 R4R4 R5R5 HNHNHNHN RESIN BEAD Combinatorial synthesis - heterocyclic synthesis 4.4 Lead compounds from the synthetic world

45. The Past Lead Compound TargetsTargets Lead compounds The Present and Future 4.5 Lead compounds - impact of the human genome project

46. 4.5 Lead compounds - impact of the human genome project

47. 4.5 Lead compounds - impact of the human genome project

48. Lead compounds - impact of the human genome project

49. 4.5 Lead compounds - impact of the human genome project

50. 4.5 Lead compounds - impact of the human genome project

51. 4.6 Lead compounds - de novo design

52. X-RAY CRYSTALLOGRAPHY

53. PROTEIN STRUCTURE 4.6 Lead compounds - de novo design

54. Receptor 4.6 Lead compounds - de novo design

55. Scaffold CO 2 - HO IONICBOND H-BOND VDWBOND Scaffold H3NH3N + O CH 3

56. N HNHNHNHN O S O O NHNHNHNHN N N H2NH2NH2NH2N S O OON Thymidylate kinase inhibitors Anticancer agent Lead compound Optimisation 4.6 Lead compounds - de novo design

57. 4.7 Design of lead compounds using NMR spectroscopy NMR spectroscopy

58. Binding Site Protein 4.7 Design of lead compounds using NMR spectroscopy

59. Protein No observable biological effect 4.7 Design of lead compounds using NMR spectroscopy

60. 13 C NMR C C CH CH CH CH 2 CH 3 4.7 Design of lead compounds using NMR spectroscopy

61. CH 2 CH 3 13 C NMR C C CH CH CH CH 2 CH 3 4.7 Design of lead compounds using NMR spectroscopy

62. Protein Optimiseepitope

63. Protein OptimiseepitopeOptimiseepitope

64. Protein OptimiseepitopeOptimiseepitope Link

65. LEAD COMPOUND 4.7 Design of lead compounds using NMR spectroscopy

66. Me Design of a lead compound as an immunosuppressant Epitope A Epitope B 4.7 Design of lead compounds using NMR spectroscopy

67. Me Design of a lead compound as an immunosuppressant Lead compound 4.7 Design of lead compounds using NMR spectroscopy