Regulatory Toxicology.docx - Regulatory Toxicology Regulatory Toxicology To use toxic substances safely Risk Assessment Paradigm Hazard Assessment

Regulatory Toxicology.docx - Regulatory Toxicology...

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Regulatory Toxicology Regulatory Toxicology: To use toxic substances safely Risk Assessment Paradigm Hazard Assessment: Identification and description of toxicological features of substances o Not an expression of risk o Not a hazard until exposed to it Dose response Evaluation: Dose determines if drug is toxic or not Exposure Assessment: Process of estimating or measuring the magnitude, frequency and during of exposure an agent Risk Characterization: Explains what you have done in the other steps Determination of Safety Risk= Hazard(Toxicity) x Exposure o As exposure increase, so does risk o By limiting a patient to a certain dose, the exposure Is less and therefore the risk is less Hazard Assessment and Dose Response Evaluation Toxicological Studies: o Acute Labelling information carried out in rats and mice Can be traditional median lethal dose or more contemporary limit study o Eye and Skin Irritancy: Typically carried out in rabbits Not needed if chemical physical properties predict irritancy o Sub-Chronic:
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Usually conducted in rats Typically periods of 90 days Most useful for planning of long term feeding studies o Chronic: Must include at least 90% of anticipated life span of test species Study parameters investigated include BW, hematology, biochemistry and gross pathology o Chronic Dog: Typically conducted for periods of 6 months to a year Almost always required in submissions intended to support food tolerances Little practical value as group sizes too small to be statistically useful o Carcinogenicity: Doses selected in part on the basis of 90 day studies and often approach an MTD for a high dose Study parameters investigated include extensive histopathology o Reproduction Testing: Provides general information concerning the effects of a test substance on male and female reproductive performance Does not evaluate birth anomalies o Teratogenicity: The property of a chemical of a chemical which causes permanent structural or functional abnormalities during the period of embryonic development Necropsy: Macroscopic examination for structural abnormalities or pathological change MTD: Highest practical dose which can be administered experimentally without affecting overall survival N.B: Dose selection is NOT intended to approximate anticipated human exposure level Carcinogens
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