Dr. Basavaraj K. Nanjwade M.Pharm., Ph.D Drug Design: Discovery, Development and Delivery – Regulatory Requirements Dr. Basavaraj K. Nanjwade M.Pharm., Ph.D Associate Professor Department of Pharmaceutics KLE University BELGAUM – 590010 E-mail: bknanjwade@yahoo.co.in Cell No: 0091 9448716277 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Design 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Design Drug design is the approach of finding drugs by design, based on their biological targets. Typically a drug target is a key molecule involved in a particular metabolic or signalling pathway that is specific to a disease condition or pathology, or to the infectivity or survival of a microbial pathogen. Other approaches may be to enhance the normal pathway by promoting specific molecules in the normal pathways that may have been affected in the diseased state. In medicine, biotechnology and pharmacology, drug discovery is the process by which drugs are designed 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Design 1. Rational Drug Design 2. Computer-assisted Drug Design (CADD) 3. Neural network in Drug Design 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Rational Drug Design The industry now has the research tools to pursue rational Drug Design successfully, but a new hurdle is being raised:finding a way to generate data and manage our knowledge of disease that maximizes the value of that knowledge 1. Molecular properties 2. Receptor-Based modeling 3. Numerical methods 21 April 2009 GCP Workshop, NIMS Hyderabad

Refining the understanding of pathogenesis Rational Drug Design Refining the understanding of pathogenesis 21 April 2009 GCP Workshop, NIMS Hyderabad

Investigating complex systems increases knowledge return Rational Drug Design Investigating complex systems increases knowledge return 21 April 2009 GCP Workshop, NIMS Hyderabad

Computer-assisted Drug Design (CADD) Drug design is a three-dimensional puzzle where small drug molecules, ligands, are adjusted to the binding site of a protein. The factors which affect the protein-ligand interaction can be characterized by using molecular docking and different quantitative structure-activity relationships (QSAR) methods 21 April 2009 GCP Workshop, NIMS Hyderabad

Computer-assisted Drug Design (CADD) In CoMFA map the colored fields describe how molecular structure can be modified to increase biological activity (CoMFA-Comparative molecular field analysis) 21 April 2009 GCP Workshop, NIMS Hyderabad

Computer-assisted Drug Design (CADD) CADD most commonly used tool to model biological system is molecular dynamics The model of a receptor refined with molecular dynamics simulations 21 April 2009 GCP Workshop, NIMS Hyderabad

Computer-assisted Drug Design (CADD) 3D models of membrane receptors can be refined and validated in a realistic lipid-water-salt environment using molecular dynamics simulations 21 April 2009 GCP Workshop, NIMS Hyderabad

Computer-assisted Drug Design (CADD) Virtual screening is a computational technique to find novel drug candidates. Data from virtual screening can be used to develop predictive models in order to optimize ADMET properties of the candidate molecules. The ultimate goal of this procedure is to find investing lead molecules that are worth for further drug research and synthesis. 21 April 2009 GCP Workshop, NIMS Hyderabad

Computer-assisted Drug Design (CADD) New potent inhibitor for the Human Sirutuin Type 2 enzyme was found using a virtual screening technique 21 April 2009 GCP Workshop, NIMS Hyderabad

Neural network in Drug Design This is the most latest technique being applied to discover new drugs. It works on the same principles as the neural networks found in the human brain. This technique makes use of Computer Artificial Intelligence, whereby a computer learns by itself, how to approach a target drug molecule and improves its iterations by itself. This technique can be applied to solve complex drug calculations. Desktop computers as well as Super-Computers both are employed for Neural Networks Drug research. 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Applications 1. Find interesting lead molecules quickly 2. Predicting properties and activities of untested molecules 3. Propose compounds for synthesis 4. Validate models of receptor binding sites 5. Optimize pharmacokinetic properties of compound 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Discovery 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Discovery In medicine, biotechnology and pharmacology, drug discovery is the process by which drugs are discovered The process of drug discovery involves the identification of candidates, synthesis, characterization, screening, and assays for therapeutic efficacy. 21 April 2009 GCP Workshop, NIMS Hyderabad

Important DRUG Targets Focused Areas of Research Metabolic Gastrointestinal Dermatology Ophthalmic Neurological/ Pyschotherapeutic Inflammatory/ Immune-related Important DRUG Targets Infectious Disease Microbial/Viral Oncology/ Cancer Cardiovascular/ Blood Disorder Musculoskeletal Respiratory 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Discovery Pathway Preclinical Studies Primary Screening [Hits] Selection of candidate drug ADME Discovery & Development Efficacy Preformulations Stability Studies Safety Toxicology Leads 21 April 2009 GCP Workshop, NIMS Hyderabad

Drug Discovery Process 1. What is an ideal drug? (Given by mouth and has a beneficial effect {safe & efficacious} in only ~ 50% !) 2. What is a promising drug candidate? (Most site specific with best combination of target affinity, highest bioavailability and lowest toxicity) 3. How is a ‘lead’ drug candidate screened for ideal characteristics? (Study of the in vitro ADME/Tox- drug transport , absorption, metabolism, etc) [Toxicity & pharmacokinetics: In vivo ] 21 April 2009 GCP Workshop, NIMS Hyderabad

Drug Discovery Pipeline Exploratory Research Discovery Development Proteomics Diagnostics Peptide Mass Expression Fingerprinting Profiling Fractionate Mass Protein Spec Validated Targets Pathway Mapping Lead Lead Pre-clinical Clinical Protein Identification Optimization Protein- protein Interactions Structure Genotyping Hot Drug ADME Human H-UHTS Genome SNP M-HTS L-MTS Leads Candidates PK Trials Sequencing Discovery Functional Genomics Primary Secondary Lab & Clinical Protein Gene Combichem Screening Screening Animal Tests Validation Expession Localization Synthesis Genomics Compound Profiling Production Library Drug Discovery Natural Compounds 21 April 2009 GCP Workshop, NIMS Hyderabad

Drug Discovery Process Exploratory Drug Discovery Drug Development Compound library generation Combichem New Drug Target Identification Qualification Validation Lead Optimization Preclinical Development Clinical NDA Clinical Trials & monitoring Assay Development Discovery Center w/primary & secondary screening & Pre-ADME In vitro & in-vivo ADMET Functional and ADMET screening assays becoming more important earlier in the screening process. 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad “Real drug “pipeline” A – Absorption Solubility Stability Dissolution Drug Transport D- Distribution Plasma Protein Binding assays (PPB) Targets “Permeability” Drug Drug Drug 21 April 2009 GCP Workshop, NIMS Hyderabad

Overview of Solubility Screening Assay Protocol 1. Compound from library is added to buffer and mixed in plate. 2. Precipitated compound is filtered out. 3. Filtrate containing soluble compound is analyzed versus standards. 21 April 2009 GCP Workshop, NIMS Hyderabad

Value of Solubility and Permeability for Absorption For a particular dose level and permeability value, the solubility must be above a certain level to assure oral bioavailability. 21 April 2009 GCP Workshop, NIMS Hyderabad

Cell Membrane Transport Mechanisms Transcellular Paracellular Active Transport Active Efflux 21 April 2009 GCP Workshop, NIMS Hyderabad

Membrane structure & transport Membranes are two-dimensional solutions of oriented lipids and globular proteins that are mobile in the plane of the membrane – fluid-mosaic model Membrane transport is mediated by specific integral membrane proteins – ion channels, porins, transporters (passive), pumps (active) Integral membrane proteins have common structural features – predominantly transmembrane a helices 21 April 2009 GCP Workshop, NIMS Hyderabad

Ion channels are membrane spanning proteins 21 April 2009 GCP Workshop, NIMS Hyderabad

Opening and closing of channels requires conformational change 21 April 2009 GCP Workshop, NIMS Hyderabad

Flux of ions through the channels is passive Extracellular Intracellular 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Development 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Development Drug development or preclinical development is defined in many pharmaceutical companies as the process of taking a new chemical lead through the stages necessary to allow it to be tested in human clinical trials, although a broader definition would encompass the entire process of drug discovery and clinical testing of novel drug candidates. 21 April 2009 GCP Workshop, NIMS Hyderabad

Drug Discovery Pathway Preclinical Studies Primary Screening [Hits] Selection of candidate drug ADME Discovery & Development Efficacy Preformulations Stability Studies Safety Toxicology Leads 21 April 2009 GCP Workshop, NIMS Hyderabad

Drug Development Process 21 April 2009 GCP Workshop, NIMS Hyderabad

Reasons for Attrition in Drug Development 21 April 2009 GCP Workshop, NIMS Hyderabad

Barriers of Drug Reaching Target Stomach pH2 Intestine pH3-8 Blood Kidneys Tissues Liver Cell Target PV Phase I and II Metabolic stability Metabolite ID Stability Enzymatic Plasma stability Permeability Passive Transporters Log D Cell Exposure Stability Acidic buffer Stability Acidic enzymatic buffer Renal Extraction Log D Protein binding RBC uptake Solubility pKa Permeability Passive P-gp efflux Transportes Log D Stability CYP3A metabolic stability 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Candidate Selection: Building “Developability” in Preclinical Profiling Lead (active molecule) Physical properties Metabolism Potency Potency Best leads Physical / chemical properties Biopharmaceutics Selectivity Metabolism Selectivity LO (optimized molecule) 21 April 2009 GCP Workshop, NIMS Hyderabad

Stability in Physiological Conditions Duodenum Stomach Ascending colon Descending colon Jejunum Ileum Small intestine Transverse colon Rectum pH = 1 - 3.5 pH = 5 - 7 pH = 8 Blood = 7.4 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Solubility, Permeability, Chemical and Metabolic Stability Affects Oral Bioavailability Portal Vein Membrane Transfer Liver Extraction Solid Drug Dissolution Drug in Solution Absorbed Drug Systemic Circulation Solubility Permeability Metabolism 21 April 2009 GCP Workshop, NIMS Hyderabad

Physico-chemical profile of NCEs 21 April 2009 GCP Workshop, NIMS Hyderabad

Successful Drug = Activity + Property Optimization Activity Pharmacology Property Pharmaceutical Profiling In vitro Solubility Permeability BBB & Pgp Log P & pKa Metabolism P450 Inhibition Stability Pharmacokinetics In vivo Enzyme Receptor Cell-based assay Animal Model Redesign 21 April 2009 GCP Workshop, NIMS Hyderabad

Drug Development Process 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Delivery 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Delivery Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals Drug Delivery technologies are patent protected formulation technologies that modifies drug release profile, absorption, distribution and elimination for the benefit of improving product efficacy & safety and patient convenience & compliance 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Delivery Most common methods of delivery include the preferred non-invasive peroral (through the mouth), topical (skin), transmucosal (nasal, buccal/sublingual, vaginal, ocular and rectal) and inhalation routes 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Delivery Many medications such as peptide and protein, antibody, vaccine and gene based drugs, in general may not be delivered using these routes because they might be susceptible to enzymatic degradation or can not be absorbed into the systemic circulation efficiently due to molecular size and charge issues to be therapeutically effective protein and peptide drugs have to be delivered by injection. 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Delivery Current efforts in the area of drug delivery include the development of targeted delivery in which the drug is only active in the target area of the body (for example, in cancerous tissues) and in which the drug is released over a period of time in a controlled manner from a formulate 21 April 2009 GCP Workshop, NIMS Hyderabad

Context – Drug Delivery 21 April 2009 GCP Workshop, NIMS Hyderabad

Context – Drug Delivery 21 April 2009 GCP Workshop, NIMS Hyderabad

Drug Delivery - Markets 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad Drug Delivery Systems 21 April 2009 GCP Workshop, NIMS Hyderabad

Regulatory Requirements 21 April 2009 GCP Workshop, NIMS Hyderabad

India (Ministry of Health & Family Welfare) 1. If the drug or its metabolites is related to a known carcinogen 2. Two species should be used for carcinogenicity studies 3. At least 3-dose level should be used 4. A control group should always be included 21 April 2009 GCP Workshop, NIMS Hyderabad

United States ( FDA’s Centre for Drug Evaluation & Research) 1. Microbial mutagenicity test 2. In vitro mammalian cell mutagenicity test 3. Mammalian chromosome test in vitro 4. In vitro mammalian cell transformation assay 5. Cytogenetic tests in vivo (e.g. bone marrow micronucleus test, liver unscheduled DNA synthesis [UDS] test). 6. Further in vivo test selection is left to the applicant 21 April 2009 GCP Workshop, NIMS Hyderabad

European Community (The Commission of the European Union) 1. An in vitro test for gene mutation in bacteria 2. An in vitro test for gene mutation in eukaryotic test system (mammalian cells) 3. An in vitro test for chromosomal aberration 4. An appropriate in vivo assay (usually test for chromosomal aberration) 21 April 2009 GCP Workshop, NIMS Hyderabad

Japan ( Ministry of Health & Welfare) 1. Bacterial reversion test 2. In vitro chromosomal aberration test 3. In vivo micronuleus test Additional tests (i) Continuous treatment for 24 and 48 hours with and without S9 mix.. (ii) Pulse treatment for 6 hours (with and without S9 mix) followed by sampling at 24 hours. (iii) Chromosome preparation for the presence of polyploid cells (iv) Use of single sex (male) in rodent micronucleus test 21 April 2009 GCP Workshop, NIMS Hyderabad

Canada (Health Protection Branch) 1. Salmonella/microsome assay. 2. Mammalian in vitro chromosome aberration assay. 3. Mammalian in vivo assay (either metaphase or micronucleus test). 4. Positive in vivo results may need additional in vivo germ cell assay 21 April 2009 GCP Workshop, NIMS Hyderabad

ICH (Regulatory authorities of EU, Japan & USA) 1. A test for gene mutation in bacteria. 2. In vitro chromosomal damage with mammalian cells or an in vitro tk assay. 3. In vitro test for chromosomal damage using rodent haemopoietic cells. Additional test: (i) Measurement of DNA adducts. (ii) DNA – strand breaks (iii) DNA repair or recombination 21 April 2009 GCP Workshop, NIMS Hyderabad

GCP Workshop, NIMS Hyderabad THANK YOU FOR YOUR ATTENTION 21 April 2009 GCP Workshop, NIMS Hyderabad