Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B. Pharmacy III MEDICINAL CHEMISTRY-I Previous Question Paper (March-2021 - R17)
Answer any five questions
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Main
Discuss the physiochemical properties of drugs in relation to biological action.
Ionization
Answer
The ionization of a drug, determined by its pKa and the pH of the biological environment, dictates its ability to cross cell membranes. According to the pH-partition hypothesis, only the unionized form of a drug is sufficiently lipophilic to diffuse through lipid bilayers, while the ionized form is generally water-soluble and essential for transport in blood or interaction with ionic receptors. The ratio of ionized to unionized drug is governed by the Henderson-Hasselbalch equation:
Hydrogen bonding
Answer
Hydrogen bonding occurs when a hydrogen atom covalently bonded to an electronegative atom (like O, N, or F) interacts with another electronegative atom. It significantly influences drug solubility, membrane permeability, and receptor-ligand binding affinity. Intramolecular hydrogen bonding can increase lipophilicity by masking polar groups, while intermolecular hydrogen bonding with water increases aqueous solubility. At the receptor site, hydrogen bonds provide specificity and stability to the drug-receptor complex.
Protein binding
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Chelation
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Discuss the factors affecting drug metabolism including stereo chemical aspects.
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Discuss the biosynthesis of catecholamines. Write about adrenergic receptor and their distribution in the body.
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What are sympathomimetic agents? Classify them. Discuss the synthesis of phenylephrine.
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Write a note on adrenergic blockers. Classify them with examples and give the mechanism of action and uses of Tolazoline.
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Discuss the biosynthesis of acetylcholine. Write about cholinergic receptors and discuss about their distribution in the body.
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Give the synthesis of Neostigmine.
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Write the synthesis and uses of Ipratropium bromide.
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What are synthesis of cholinergic blocking agents? Classify them with examples and give their mechanism of action and uses.
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Give the synthesis of Diazepam.
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Discuss elaborately the SAR of Barbiturates.
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Discuss the SAR of Morphine analogues.
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Give the synthesis of Mefenamic acid.
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