Principles of genotoxicity and teratogenicity as per OECD guidelines

Introduction

Understanding the principles of genotoxicity and teratogenicity is essential for pharmacy students and aspirants preparing for competitive examinations such as GPAT, NIPER, UPSC Drug Inspector, AIIMS Pharmacist, Railway Pharmacist, SSC, ESIC, and State Pharmacist examinations. These topics form an important part of toxicology, drug safety, preclinical evaluation, and regulatory science.

Genotoxicity refers to the ability of a substance to damage genetic material, including DNA and chromosomes. Such damage may result in gene mutations, chromosomal aberrations, chromosome breakage, or abnormal chromosome segregation. In contrast, teratogenicity refers to the ability of an agent to interfere with normal embryonic or fetal development, potentially causing developmental abnormalities, growth retardation, or embryo-fetal death.

The Organisation for Economic Co-operation and Development (OECD) provides internationally recognised test guidelines for evaluating the safety of chemicals and pharmaceutical substances. Important genetic toxicology guidelines include OECD TG 471 for the Bacterial Reverse Mutation (Ames) Test, TG 473 for chromosomal aberration testing, TG 474 and TG 487 for micronucleus tests, and TG 489 for the in vivo Comet Assay. OECD TG 414 is particularly important for understanding prenatal developmental toxicity.

For competitive examinations, students should focus not only on definitions but also on the principles of each test, the type of genetic damage detected, important OECD guideline numbers, metabolic activation, clastogenicity, aneugenicity, critical periods of development, and the difference between genotoxicity and teratogenicity.

The following easy-to-revise notes and challenging MCQs with explanations will help strengthen conceptual understanding and prepare students for both direct and tricky examination questions.

Click the link below to access notes and MCQs

https://drive.google.com/file/d/15nhZDEfNwL0GFHSTAYRcYJdxJLT2I9ZH/view?usp=drive_link