Preclinical Phase Drug Discovery And Development PDF

DRUG DISCOVERY AND DEVELOPMENT Module 3: PRECLINICAL PHASE KYLE CHRISTIAN VREELAND, RPh Lecturer P R E PA R E D B Y: RICARDO JR. N. ARELLANO CEU-SCHOOL OF PHARMACY  MODULE OUTLINE TOP IC H IGH LIGH T S Preclinical Trials...

DRUG DISCOVERY AND DEVELOPMENT Module 3: PRECLINICAL PHASE KYLE CHRISTIAN VREELAND, RPh Lecturer P R E PA R E D B Y: RICARDO JR. N. ARELLANO CEU-SCHOOL OF PHARMACY  MODULE OUTLINE TOP IC H IGH LIGH T S Preclinical Trials Types of Toxicity Testing Common Validated In Vitro and In Vivo Toxicology Methods Guidelines for Ethical Conduct in the Care and Use of Animals for Preclinical Trials in Drug Testing Preclinical Trials Module 3: Preclinical Phase Preclinical Phase “Preclinical trials or nonclinical trials” Laboratory test of a new drug substance or medical devices, usually done on animal subjects –Determines a products’ ultimate safety profile –Develop adequate safety data before human trial –Part of INDA 4 Module 3: Preclinical Phase Preclinical Trials- Clear Bird Eye view Source: https://youtu.be/ylyzl_u6oMQ 5 Module 3: Preclinical Phase Terms: In vitro test - performed outside of a living organism In vivo test - performed in living organisms OECD - Organization for Economic Co-operation and Development TG – Test Guidelines GSH - Globally Harmonized System 6  Types of Toxicity Testing Module 3: Preclinical Phase Types of Toxicity Testing 1. Acute toxicity testing Single high doses are given to small groups of animals Observed for mortality for 1-3 days Organ toxicity is examined by histopathology Lethal dose (LD50) - dose which kills 50% animals –Involves large numbers of animals, 14 days observation 8 Module 3: Preclinical Phase Fixed Dose Procedure (FDP) - TG 420 5 50 500 2000 9 Module 3: Preclinical Phase 10 Module 3: Preclinical Phase Fixed Dose Procedure (FDP) – TG 420 5 50 500 2000 11 Module 3: Preclinical Phase Acute toxic class (ATC) method - TG 436 12 Module 3: Preclinical Phase Up-and-down (UDP) method – TG 425 13 Module 3: Preclinical Phase Types of Toxicity Testing 2. Repeated dose toxicity testing Carried out for a minimum of 28 days The test substance is administered regularly at a specific time. 14 Module 3: Preclinical Phase Types of Toxicity Testing 3. Sub-chronic oral toxicity testing The test substance is administered orally for 90 days. The test substance is administered regularly at a specific time. 15 Module 3: Preclinical Phase Types of Toxicity Testing 4. Chronic oral toxicity testing The test compound is administered over more than 90 days, and the animals are observed periodically. Provides inferences about the long-term effect of a test substance Essential for new drug entities. 16 Module 3: Preclinical Phase Types of Toxicity Testing 5. Neurotoxicity studies Studies the effects of a test substance on the CNS 6. Carcinogenicity testing Observed for signs of toxicity and development of tumors. 18 months for mice and hamsters; 24 months for rats 17 Module 3: Preclinical Phase Types of Toxicity Testing 7. Mutagenicity testing Assess submicroscopic changes in the base sequence of DNA –Mutagenicity: permanent transmissible variations that can increase the frequency of mutations. 18 Module 3: Preclinical Phase Types of Toxicity Testing 8. Genotoxicity testing Used to identify gene mutations, chromosome changes, and alterations in the DNA sequencing – Genotoxicity: ability of harmful substances to damage genetic information 19 Module 3: Preclinical Phase Types of Toxicity Testing 9. One-generation reproduction toxicity testing Rodents are preferred (M and F) Observed for 1 spermatogenic cycle and 2 estrous cycles Animals are allowed to mate and parturition is observed. 10. Two-generation reproduction toxicity testing 20 Module 3: Preclinical Phase Types of Toxicity Testing 11. Developmental toxicity/embryotoxicity studies The compound is administered between the 8th and 14th day of pregnancy, and embryolethal effects is observed. At the end of the study or on the 21st day of the study, a caesarean section is performed and parameters such as fetal deformation and mortality are observed. 21 Module 3: Preclinical Phase Types of Toxicity Testing 12. Toxicokinetics Deals with the kinetic patterns of higher doses of chemicals/toxins/xenobiotics 22 Module 3: Preclinical Phase Animal Used in Preclinical trials DRUGS ANIMALS Chorionic Gonadotropin Female rat (20-23 days old) Cod Liver oil Spectrophotometer (Rachitic rat) Corticotropin Injection Rat same but of either sex Digitalis Pigeon Glucagon injection Cat Heparin Sheep blood plasma 23 Module 3: Preclinical Phase Animal Used in Preclinical trials DRUGS ANIMALS Insulin injection HPLC (rabbit) Metocurine injection HPLC (rabbit) Oxytocin injection Chicken Protamine sulfate Sheep blood plasma Tubocurarine HPLC (rabbit) Vasopressin Male rat 24 Module 3: Preclinical Phase Animal Used in Preclinical trials For Biological Reactivity Tests Invitro ANIMALS Systemic injection test Abino Mice Intracutaneous Test Albino Rabbits Implantation Test Rabbits Eye irritation Test Albino rabbits 25  Common Validated Toxicology Methods Module 3: Preclinical Phase Terms: In vitro test - performed outside of a living organism In vivo test - performed in living organisms OECD - Organization for Economic Co-operation and Development TG – Test Guidelines GSH - Globally Harmonized System 27 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals Skin corrosion –irreversible damage to the skin. Skin irritation –reversible changes following the application of a test substance for up to 4 hours. 28 Module 3: Preclinical Phase 29 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals Dose Descriptor for Skin/Eye Irritation –No Observed Adverse Effect LeveL (NOAEL) cannot be obtained from skin/eye irritation tests due to study design. –Approach: Qualitative risk characterization based on potency categorization (yes or no, corrosive, strong, mild) 30 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals A. Skin Irritation 1. In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Te st 2. In Vitro Skin Corrosion: Human Skin Model Test 3. In Vitro 3T3 NRU Phototoxicity test 4. In Vitro Membrane Barrier Test Method for Skin Corrosion 5. In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method 6. In vivo Acute Dermal Irritation / Corrosion 31 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals Serious eye damage –tissue damage in the eye, or serious physical decay of vision, following the application of a test substance to the front outer surface of the eye, which is not fully reversible within 21 days. Eye irritation –changes in the eye following application of a test substance to the front outer surface of the eye, which is fully reversible within 21 days. 32 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals B. Serious Eye Damage/Eye Irritation 1. In Vitro Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants 2. In Vitro Fluorescein Leakage Test Method (FL) 3. In Vitro Short Time Exposure Test Method (STE) 4. In Vitro Reconstructed human Cornea-like Epithelium Test Method (RhCE) 5. In vivo Acute Eye Irritation / Corrosion 33 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals B. Serious Eye Damage/Eye Irritation Draize tests on rabbits and guinea pigs for 14 days Eye: Redness, swelling, discharge, ulceration, hemorrhage, and blindness Skin: erythema and edema 34 Module 3: Preclinical Phase 35 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals Sensitizer –an agent that can cause an allergic response in animals or humans. –If skin is exposed to a sensitizing chemical substance, allergic contact dermatitis or atopic dermatitis may be provoked. 36 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals C. Sensitization 1. In Vitro Skin Sensitization: ARE-Nrf2 Luciferase Test Method 2. In Vitro Skin Sensitization: Human Cell Line Activation Test (h- CLAT) 3. In vivo Skin sensitization: Local Lymph Node Assay (LLNA) » Most frequently used 4. In vivo Skin sensitization: the guinea pig maximization test (GPMT) and the Buehler test 37 Module 3: Preclinical Phase Common validated toxicology testing methods for chemicals D. Genotoxicity 1. In Vitro Bacterial reverse mutation test (Ames test) 2. In Vitro mammalian chromosome aberration test 3. In Vitro mammalian cell gene mutation test 38 Module 3: Preclinical Phase 39 Module 3: Preclinical Phase Factors to Consider When Using In Vitro Methods 1. Know whether in vitro methods are accepted by regulatory authority in your jurisdiction or not. 2. Consider animal welfare issue. 3. Know the limitations of in vitro methods. 40  Guidelines for Ethical Conduct in the Care and Use of Animals for Preclinical Trials in Drug Testing Module 3: Preclinical Phase Guidelines for Ethical Conduct in the Care and Use of Animals for Preclinical Trials in Drug Testing Department of Agriculture’s (DA) Bureau of Animal Industry (BAI) –Animal Welfare Act of 1998 (Republic Act No. 8485 42 Module 3: Preclinical Phase Administrative Order (AO) No. 40. The requirements for the authorization to conduct research using animals are the following: (1) Description of the Animal Care and Use Program (ACUP) signed by a duly licensed veterinarian representing the entity, (2) Animal Care and Use Program Accreditation Certificate issued by a duly recognized body or association, (3) Animal Technician Training Program on Laboratory animal care and use, and (4) Certification of Assurance that an Institutional Animal Care and Use Committee (IACUC) is in existence in the establishment. 43 Module 3: Preclinical Phase Ethical Consideration in Animal Experimentation – 3R’s Replacement Reduction Refinement 44 END OF PRESENTATION For questions, you can message your teacher in CEU LEAPS.