JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D V Year CLINICAL RESEARCH Previous Question Paper (October - 2019 - R08)

Drug characterization is a critical phase in drug discovery that involves determining the physical, chemical, and biological properties of a lead compound. This process ensures that the molecule is suitable for further development and clinical testing.

• Physicochemical Profiling: Determination of molecular weight, solubility, lipophilicity (LogP), and pKa. These properties dictate the drug's absorption, distribution, metabolism, and excretion (ADME) profile.
• Structural Elucidation: Use of analytical techniques such as Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), and X-ray crystallography to confirm the chemical structure and purity of the lead compound.
• Stability Testing: Assessment of the compound's stability under various conditions, including pH, temperature, and light, to ensure it remains active and safe during storage and administration.
• Biological Characterization: Evaluation of the compound's potency, selectivity, and mechanism of action through in vitro assays to confirm its therapeutic potential against the target receptor or enzyme.

The dosage form is the physical manifestation of a drug product, designed to deliver the active pharmaceutical ingredient (API) to the site of action in an effective and safe manner. Selecting the appropriate dosage form is essential for optimizing bioavailability and patient compliance.

• Oral Dosage Forms: These include tablets, capsules, and oral solutions. They are the most common due to convenience and patient acceptance. Formulation strategies like enteric coating or sustained-release mechanisms are used to control the drug release profile.
• Parenteral Dosage Forms: Sterile preparations such as injections or infusions, used when rapid onset of action is required or when the drug has poor oral bioavailability due to first-pass metabolism.
• Topical and Transdermal Forms: Creams, ointments, and patches designed for localized effect or systemic absorption through the skin, bypassing the gastrointestinal tract.
• Formulation Development: This involves selecting suitable excipients (binders, disintegrants, stabilizers) to ensure the drug remains stable, compatible, and bioavailable within the chosen delivery system.