JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Pharmacy IV Year COMPUTER AIDED DRUG DESIGN Previous Question Paper (September-2021 - R17)

Drug discovery and development is a multi-stage process designed to identify and bring safe, effective therapeutic agents to market. The stages are as follows:

1. Target Identification and Validation: Identifying a biological target (e.g., protein, enzyme, receptor) associated with a disease and confirming its role in the disease pathology.
2. Lead Discovery: Identifying compounds (leads) that interact with the target. This involves high-throughput screening (HTS) or structure-based design.
3. Lead Optimization: Modifying the chemical structure of the lead compound to improve potency, selectivity, pharmacokinetic properties (ADME), and reduce toxicity.
4. Preclinical Development: Conducting in vitro and in vivo studies to assess safety, toxicity, and efficacy in animal models.
5. Clinical Trials: Testing in humans in three phases: Phase I (safety/dosage in healthy volunteers), Phase II (efficacy/side effects in patients), and Phase III (large-scale confirmation of efficacy and safety).
6. Regulatory Approval and Post-Marketing Surveillance: Submission of data to regulatory agencies (e.g., FDA) for approval, followed by Phase IV monitoring for long-term safety.

Analog-based drug design involves modifying the structure of a known active compound to improve its pharmacological profile. Two notable case studies include:

1. Development of Sulfonamides: Following the discovery of Prontosil, which was a prodrug, researchers identified that the active moiety was sulfanilamide. By modifying the structure of sulfanilamide, scientists created a series of analogs with improved solubility, reduced toxicity, and broader antibacterial spectra, leading to the development of drugs like sulfamethoxazole.
2. Development of H2-Receptor Antagonists: Starting with the structure of histamine, researchers sought to block its action on gastric acid secretion. By systematically modifying the imidazole ring and the side chain of histamine, they developed burimamide, then metiamide, and finally cimetidine. Cimetidine became a landmark drug for treating peptic ulcers by optimizing the analog structure for potency and safety.