New drug development naser

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  • Qualities of A DrugEffectiveSuitableSafeAffordable
  • Since the sword symbolizes strength and power, the early
  • Paracelsus: He was a controversial figure who has been portrayed as both ignorant and superstitious. He had no medical degree. He burned the classical medical works of Galen and Avicenna before his lectures in Basel (Switzerland) and had to leave the city following a dispute about fees with a prominent churchman. He died in Salzburg (Austria) either as a result of a drunken debauch or because he was thrown down a steep decline by ‘hitmen’ employed by jealous local physicians. But he was right about the dose, “The dose alone decides that something is no poison”
  • Made its debut in 19th century Isolation of streptomycin by Waksman (1944) from Streptomycesgriseus after screening of 10,000 microorganism samples(random screening )
  • physiological., biochemical
  • Antimetabolites
  • Computer analysis is done to identify putative drugs which are then subjected to conventional tests
  • Therapeutic proteins produced by genetic engineeringStarted with synthesis of Human Insulin in 1982Scope broadened with time which includes proteins, nucleic acids, vaccines and even cell-based therapies
  • ["first-in-man" (FIM) or First Human Dose (FHD)].
  • Screening Tests: Simple, rapid tests – indicate presence / absence of a pharmacodynamic activityGeneral observational test: Performed either in the beginning in case of totally novel compounds or after detecting usefulness in screening test. The drug is injected in tripling doses to small group of animals (mice) and the animals are observed for any overt effects. Preliminary clues are drawn from the profile of effects observed.
  • Acute toxicity studies:single escalating doses are given to small group of animals that are observed for overt effects and mortality for 1- 3 days. The dose which kills 50 % of animals LD50 is calculated
  • These studies are undertaken to generate data by which the hazards and risks to users, consumers and third parties, including the environment, can be assessed for pharmaceuticals (only preclinical studies), GLP helps assure regulatory authorities that the data submitted are a true reflection of the results obtained during the study and can therefore be relied upon when making risk/safety assessments.
  • Adherence to GCP provide assurance thatRights, integrity and confidentiality of trial subjects are protectedData and reported results are credible and accurate
  • New drug development naser

    1. 1. New Drug Development
    2. 2. What is a drug?
    3. 3. Drug• Single chemical entity present in the medicine used for diagnosis, prevention or cure of a disease.• WHO: – Any substance or a product that is used or intended to be used to modify or explore the physiological systems or pathological states for the benefit of the recipient
    4. 4. New Drug• A substance of chemical, biological or biotechnological origin for which adequate data is not available for the regulatory authority to judge its efficacy and safety for the proposed claim.
    5. 5. Not a Easy Process• Highly complex• Tedious• Competitive• Costly (500 – 1000 million dollars)• Commercially risky• Time consuming (at least 10 years)
    6. 6. Stages in the new drug development• Synthesis & isolation of compound – New chemical entity (NCE) – Takes 1-2 years• Preclinical studies – 2-4 years• Investigational New Drug Application (IND) – Submission & review by FDA – 3-6 months
    7. 7. Stages in the new drug development IND Clinical Trials Pre clinical studies continued •Phase 1 Plus •Phase 2 •Long term animal toxicity •Phase 3 •Product formulation 3 To 10 years •Manufacturing & controls •Package & label designs New Drug Application (NDA) •Review & grant of marketing permission •0.5 to 2 years Post marketing surveillance (Phase -4)
    8. 8. Old methods of Drug Discovery• Use crude plant / animal products / minerals to treat disease (India, China, Egypt and Babylon)• No study before using them. Agents were selected on the basis of their symbolic qualities & astrological signs – Greek physicians used iron against weakness. – Horn of rhinoceros as a potent aphrodisiac. – many obnoxious remedies, like flesh, excreta & blood of various animals were used• Drugs were added by considerable trial and error
    9. 9. Galen• Concept of polypharmacy• Mixed vegetable crude drugs from Aelius different sources Galenus or Claudius• Galen’s name is retained in the Galenus (AD 129 – 200/217), better term ‘galenical’ for preparation of known as Galen of Pergamum crude vegetable drugs
    10. 10. Paracelcus• Paracelsus (AD 1493 – 1541) criticized the polypharmacy of mixed vegetable preparations of Galen• Pioneered the use of chemicals and minerals in medicine.• He introduced the use of mercury in the treatment of syphilis.• "All things are poison and nothing is without poison, only the dose permits something not to be poisonous."
    11. 11. Important contributions– 1847: Birth of Pharmacology as a scientific discipline by Rudolf Buchheim at Dorpat– 1878: Louis Pasteur’s “germ theory” of disease at Paris– 1890s: The “magic bullet theory” of Paul Ehrlich
    12. 12. Approaches to drug discovery• Natural sources• Chemical synthesis• Rational approach• Molecular modelling• Combinatorial chemistry• Biotechnology
    13. 13. Natural sources• Plants – Morphine, Ephedrine, reserpine, artermisinin, quinine, atropine• Animals – Adrenaline, thyroxine, insulin, liver extract, antisera• Micr-organisms – Penicillin, cephalosporin
    14. 14. Morphine from Opium Friedrich Wilhelm Adam Sertürner• 1805: Friedrich Serturner, a junior apothecary in Westphalia, Germany isolated and purified morphine.• He barely survived the test of its potency on himself.• He called the isolated alkaloid "morphium" after the Greek god of dreams, Morpheus.• First person to isolate the active ingredient associated with a medicinal plant or herb
    15. 15. Indian Contribution• Rauwolfia alkaloid form Raulwofia serpentina as antihypertensive and antipsychotic drug• Gugulipid from Tinospora as lipid- lowering agent
    16. 16. Chinese Contribution• Sympathomimetic Ephedrine from Ma huang (Ephedra vulgaris)• Antimalaial Artemisinin from Quinghasou (Artemisia annua)• Anticancer drug Camptothecin (Irinotecan and topotecan) from Captotreca acumunata
    17. 17. Chemical synthesis• Randomly synthesized compounds tested for pharmacological activity – Barbiturates, chlorpromazine synthesized by this approach• Synthesis of chemical congeners – More rational – Me too drugs fathered by lead compounds – Thiazide drugs from acetazolamide, TCA from phenothiazines – Structure activity relationship – Enantiomers• Serendipity
    18. 18. Loop Diazoxide Diuretics (Anti-hypertensive) Thiazide DiureticsCarbimazole, SulfonylureasMethimazole CA inhibitors (Oral(Anti-thyroid (Diuretics) Hypoglycaemic Drugs) agents) Sulthiam SULPHONAMIDES (Anti-epileptic) Dapsone (Anti-leprotic) Cotrimoxazole
    19. 19. Drug Discovery by Serendipity• 1785: Withering’s discovery of Digitalis in treating cardiac failure (dropsy)• 1914: Wenkeback’s discovery of antidysrhythmic effect Quinidine when treating a patient with malaria who also happened to suffer from atrial tachycardia.• 1937: Use of amphetamine in treatment of attention deficit hyperactivity disorder (ADHD) by Bradley
    20. 20. Sidenafil as anti-impotence Drug• Sildenafil citrate (vigra), an anti- impotence drug. It was initially studied for use in hypertension and angina pectoris. Phase I clinical trials under the direction of Ian Osterloh suggested that the drug had little effect on angina, but that it could induce marked penile erections.
    21. 21. Enantiomers• Many drugs are having two types of 3D structure (chiral compounds) – Enantiomeres: ‘R’ & ‘S’; l & d – Combination of both (recemate)• Enantiomers are non superimposable mirror images (• Enantiomers of chiral drugs differ in biological activity, metabolic degradation etc.• Single enantiomer of a drug may be better to its racemate• E.g dextro dopa more toxic than levo dopa
    22. 22. • Now Regulatory authority grants permission after chiral separation of recemate drugs when a single enantiomer is better than the recemate preparation
    23. 23. Drugs as single enantiomers• Antihypertensive – (S) atenolol : 50% dose, better tolerated – (S) metoprolol : 50% dose – (S) amlodipine : 50% dose, better tolerated• Proton-pump inhibitors in peptic ulcer – (S) omeprazole (esomeprazole) : bioavailability – (S) pantoprazole: More potent• Anti-asthmatic drug – (R) Salbutamol: More active, ‘S’ antagonizes ‘R’
    24. 24. Drugs as single enantiomers• Antidepressant (SSRI) – (S) Citalopram (escitalopram) : dose, S/E• Chemotherapeutic Agent – Levofloxacin (l –isomer): more active, slower elimination• Antihistamine – Levocetirizine (l-isomer): 50% dose as ‘d’ form is inactive – Desloratadine (d-isomer) : 50% dose
    25. 25. Rational approach• Depends on sound knowledge & identification of specific target for drug action• Receptor based approach ( target oriented)
    26. 26. Target oriented approach• Receptors – GPCR, Receptors with intrinsic ion channels, enzyme linked receptors, Receptor regulating gene expression.• Ion channels – Na+, K+, Ca++ and Cl–• Transporters – Na+/K+ ATPase, H+/K+ ATPase, Na+-K+-2Cl–• Enzymes
    27. 27. Combinatorial Chemistry• Chemical groups are combined in random manner to yield innumerable compounds• These compounds subjected to high through put screening on cells, genetically engineered microbes, enzymes, enzymes in robotically controlled automated assay systems
    28. 28. Biotechnology• Hormones – Insulin, Growth hormones, Erythropoietin• Growth factors – GM-CSF• Cytokines – Interleukins• Monoclonal Antibodies – Trastuzumab, Rituximab, Omalizumab etc.• DNA products – Antisense oligonucleotides: Vitravene• Enzymes: – Cerebrosidase, Dornase, Galactosidase
    29. 29. Drug Development1. Pre-clinical Study – ADME – Safety and Toxicity prior to human trial – FIM (First in Man) / FHD (First Human Dose)2. CMC (Chemistry, Manufacturing & Control)3. Clinical Study – Phase I, II & III4. Registration5. Phase IV (Post-marketing Surveillance)
    30. 30. Pre-clinical study• Aim: – Is it effective? – Is it not toxic? – Is its side effect is minimum?• Test is done on – Cultured cell line – Isolated organ – Intact animals
    31. 31. Preclinical StudiesSynthesis / Identification of Lead Compound(s) (Thousands) Few out of Thousands
    32. 32. Pre-clinical Studies• Screening Tests• Tests on isolated organs• Tests on bacterial cultures• Tests on animal models of human diseases – Diabetic rats / dogs by diazoxide – Kindled animals for anti-epileptic drugs• General observational tests on intact animals
    33. 33. Preclinical Studies• Pharmacokinetics• Systemic pharmacodynamics• Study of Mechanism of Action• Quantitative tests – Dose-Response Relationship – Maximal Effect – Efficacy testing in relation to existing drugs• Toxicity Studies
    34. 34. Toxicity Studies• Acute Toxicity Studies (1 – 3 days) – LD50 – Organ toxicity• Subacute Toxicity Studies (2 – 12 weeks) – Therapeutic index, Eating behavior, Wt, Haematology• Chronic Toxicity Studies (6 – 12 months)• Special Long-term Toxicity Studies (after 1 Ph) – Reproduction ( including Teratogenicity) – Mutagenicity – Carcinogenicity
    35. 35. Good Laboratory Practice (GLP)• Embodies a set of principles that provides a framework within which laboratory studies are planned, performed, monitored, recorded, reported and archived.
    36. 36. Before Clinical Studies• Drug is formulated into a suitable dosage form• The clinical trials are done under the guideline of Good Clinical Practice (GCP) laid down by International Conference on Harmonization (ICH)
    37. 37. Investigational New Drug (IND)• IND license is obtained after successful completion of pre-clinical studies from regulatory authorities.• Regulatory Authority – India: Drug Control General of India (DCGI) – USA: FDA (Food and Drug Administration)
    38. 38. Good Clinical Practice (GCP)• GCP include – protection of human rights as a subject in clinical trial. – provides assurance of the safety and efficacy of the newly developed compounds.• Good Clinical Practice Guidelines include standards on – how clinical trials should be conducted, – define the roles and responsibilities of clinical trial sponsors, clinical research investigators, and monitors.
    39. 39. Why Clinical Trials?• To discover or verify: – Pharmacodynamics (how it works) – Pharmacokinetics (what happens to it) – Therapeutic effects (efficacy) – Adverse reactions (safety)
    40. 40. History of Clinical TrialClinical trials for cureof scurvy in 1747 James Lind
    41. 41. JAMES LIND, CONQUERER OF SCURVY
    42. 42. Regulatory Process in Drug trial• 1937: Use of diethylene glycol as a solvent for sulfonamide preparation caused death of 107 in USA.• 1938: FDA revised its old rules and made it compulsory to demonstrated safety before marketing
    43. 43. Regulatory Process in Drug trial • 1959: Thalidomide Disaster in Europe and Australia • 10,000 cases of severe congenital malformation cases were seenPhocomelia = Greek phoco-, "seal (flipper)" +Greek melia, "limb, extremity" = human limb like a seals
    44. 44. Unethical trial• In 1932, a clinical trial named Tuskegee was conducted in patients with syphilis in USA. Study group comprised of 400 African-American poor men with syphilis. Control group was 200 healthy men. The doctors offered treatment without paying; but they only observed the patients without treatment during many years without telling anything. Ten years later, death rate was two-fold in the study group. Penicillin was developed in 1952. No patient was administered any antibiotics including penicillin until the end of study in 1972.
    45. 45. New York Times described this study as“The longest clinical trial in human body without treatment in the medical history”
    46. 46. May 16, 1997 Tuskegee trialPresident Clinton apologised from USA citizensbecause of Tuskegee trial
    47. 47. Phases of Clinical Trials• Phase I Early Clinical Pharmacology & Safety• Phase II Therapeutic exploration and dose ranging• Phase III Therapeutic confirmation and comparison• Phase IV Post-marketing Surveillance / Studies
    48. 48. Phases of Clinical Trials• In Each Phase – Exposure to greater numbers of human subjects to the drug – Collection of increasing amounts of data on safety and efficacy of the drugI II III IV
    49. 49. PHASE I• First study done on healthy human volunteers (sometimes in patients)• N = 20 – 40• Carried out by qualified clinical pharmacologists or trained physicians• Venue: A place where all vital functions are monitored and emergency / resuscitative facilities are available• No blinding, open label• Duration of study: 1 yr (approximately)
    50. 50. PHASE I• Emphasis : Safety and Tolerability• Started with lowest estimated dose and stepwise increased to effective dose.• Data collection on – Pharmacokinetics – Systemic pharmacodynamics – General adverse effects• Acceptable dosing level is found• Provisional safe dosage established
    51. 51. PHASE II• Patients suffering from the disease• Inclusion and exclusion criteria are fixed• N = 100 – 400• Carried out by physicians who are trained as clinical investigators• Duration: 2-3 years• Type: Open label / Blind• Venue: 2 - 4
    52. 52. PHASE II• Establishment of therapeutic efficacy• Define most appropriate dose range and ceiling effect in a controlled setting• Study of tolerability and pharmacokinetics as an extension of Phase I
    53. 53. PHASE III• Randomized• Placebo controlled• Comparative• Double-blind• Multi-centric• Patients study• Involves several physicians• N = 500 to 3000
    54. 54. PHASE III• Value of the drug in relation to existing therapy• Safety, tolerability, drug interactions• Additional information on pharmacokinetic data• Finalization of indication• Formulation of guidelines for therapeutic use
    55. 55. Registration• New Drug Application (NDA) along with the Data (safety and efficacy) of Clinical Trials are submitted to relevant Regulatory Authority – India: DCGI (Drug Controller General of India) – USA: FDA (Food and Drug Administration)• Chirality of drug is considered by RA• Regulatory Authority, in convinced, gives a ‘marketing permission• Average time for approval: 2.5 yr
    56. 56. PHASE IV:Post-marketing Surveillance (PMS)• Clinical trials do not end with approval• Practicing physicians are indentified and from them data are collected on a structured proforma regarding – Efficacy – Acceptability – Adverse effects• n = 4000 – 5000 patients or more
    57. 57. PHASE IV:Post-marketing Surveillance (PMS)• Uncommon adverse effects• Long term adverse effects• Adverse drug reactions (e.g. idiosyncrasy etc.)• Unsuspected drug interactions• Patterns of drug utilization• Additional indications
    58. 58. PHASE IV: Post-marketing Surveillance (PMS)• Effect on special groups – Elderly & Neonates – Pregnancy & Lactation – Liver &Renal impairment• Exploration of possibilities – Modified release dosage form – Additional route of administration – Fixed dose combination• Even drugs / formulations are withdrawn from the market if found to be injurious to health
    59. 59. Examples of drug withdrawal• Antihistamine: Terfenadine, Astemizole for producing “torsa de pointes”• Selective COX-II inhibitor: Rofecoxib and Celecoxib for producing cardiotoxicity• NSAIDs: Nimesulide is banned for all age groups in Western countries and for paediatric age group in India• Aspirin liquid formation: due to possibilities of producing Reye’s Syndrome in children
    60. 60. Phase 0 (Human Micro-dosing)• Offers a way of developing drugs in a faster, more cost effective and ethical way than ever before.

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