Ans them according to marks
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Finding Sources
Finding Sources
Finding Sources
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The library doesn't have a dedicated pharmaceutical chemistry textbook. I'll answer comprehensively from my pharmaceutical chemistry knowledge, which is well within my training for a D. Pharmacy 1st Year syllabus.
D. Pharmacy 1st Year — Pharmaceutical Chemistry (ER-20-12T)
Max Marks: 80 | Time: 3 Hours
PART – I (6 × 5 = 30 Marks) — Attempt any SIX
Q.1(a) Explain the importance of limit tests. Describe the principle and procedure of limit test for chlorides. (5 Marks)
Importance of Limit Tests
Limit tests are quantitative or semi-quantitative tests used to identify and control the amount of impurities present in pharmaceutical substances. They are important because:
- Impurities affect safety of the drug — toxic impurities can harm the patient.
- They affect the stability of a formulation — impurities can cause degradation.
- They ensure quality and purity of official drugs as per pharmacopoeial standards (I.P., B.P., U.S.P.).
- They determine whether a substance contains impurities beyond the permissible limit.
- They are relatively simple, rapid, and reproducible tests compared to exact quantitative analysis.
Limit Test for Chlorides
Principle:
The test is based on the reaction of chloride ions (Cl⁻) in the sample with silver nitrate (AgNO₃) in the presence of dilute nitric acid (HNO₃) to form a white colloidal precipitate of silver chloride (AgCl). The turbidity (opalescence) produced by the sample is compared visually with a standard solution containing a known amount of chloride.
Reaction:
Cl⁻ + AgNO₃ → AgCl↓ (white precipitate/opalescence) + NO₃⁻
Reagents Required:
- Dilute nitric acid (HNO₃)
- Silver nitrate solution (AgNO₃, 2% w/v)
- Standard chloride solution (0.001 M HCl — 1 mL = 0.0355 mg of Cl)
Procedure (I.P. Method):
- Dissolve the prescribed amount of sample in distilled water in a Nessler cylinder (50 mL).
- Add 1 mL of dilute nitric acid and dilute to 45 mL with distilled water.
- Add 1 mL of 2% AgNO₃ solution; mix and allow to stand for 5 minutes.
- In a second Nessler cylinder (standard), pipette the prescribed volume of standard chloride solution (e.g., 1 mL = 35 ppm Cl), add 1 mL HNO₃, dilute to 45 mL, and add 1 mL of 2% AgNO₃.
- Compare both cylinders transversely against a black background in diffused light.
- The opalescence produced in the test solution should not be greater than that in the standard.
Result: If turbidity of test ≤ turbidity of standard → sample passes the limit test.
Q.1(b) Discuss acid-base titration with suitable examples. Explain indicators used in acid-base titration. (5 Marks)
Acid-Base Titration
Acid-base titration is a type of volumetric analysis in which a solution of known concentration (standard solution/titrant) is used to determine the unknown concentration of an acid or base. The reaction involves neutralization:
Acid + Base → Salt + Water
Examples:
- Titration of HCl with NaOH: HCl + NaOH → NaCl + H₂O
- Assay of Sodium Hydroxide using standard sulphuric acid (I.P.)
- Assay of Ferrous Sulphate Tablets using potassium permanganate
- Titration of sodium carbonate with HCl: Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂
Types of Acid-Base Titration:
| Type | Titrant | Analyte |
|---|---|---|
| Acidimetry | Standard acid (HCl, H₂SO₄) | Base (NaOH, Na₂CO₃) |
| Alkalimetry | Standard base (NaOH) | Acid (HCl, acetic acid) |
| Non-aqueous titration | Perchloric acid in glacial acetic acid | Weak bases (amine drugs) |
Indicators in Acid-Base Titration
An indicator is a weak organic acid or base that changes colour at a specific pH range, signalling the endpoint of titration.
| Indicator | pH Range | Colour Change (Acid → Base) | Used For |
|---|---|---|---|
| Phenolphthalein | 8.3 – 10.0 | Colourless → Pink | Strong acid + Strong base; weak acid + strong base |
| Methyl orange | 3.1 – 4.4 | Red → Orange/Yellow | Strong acid + weak base (e.g., HCl + Na₂CO₃) |
| Methyl red | 4.4 – 6.2 | Red → Yellow | Weak acid + strong base |
| Litmus | 5.0 – 8.0 | Red → Blue | General, less sharp endpoint |
| Bromothymol blue | 6.0 – 7.6 | Yellow → Blue | Near-neutral titrations |
Mixed Indicator: Methyl red + Bromocresol green — gives a very sharp endpoint.
Theory of Indicators (Ostwald's Theory): The acid form and base form of the indicator have different colours. At the endpoint, the ratio [In⁻]/[HIn] changes, causing colour change.
Q.1(c) Describe classification, preparation and uses of haematinics with examples. (5 Marks)
Haematinics
Haematinics are drugs that provide essential nutrients required for the formation of red blood cells (erythropoiesis) and haemoglobin synthesis. They are used to treat various types of anaemia.
Classification
- Iron preparations — for iron-deficiency anaemia
- Vitamin B₁₂ (Cyanocobalamin) — for megaloblastic / pernicious anaemia
- Folic acid — for megaloblastic anaemia
- Erythropoietin — recombinant hormone for renal anaemia
A. Iron Preparations
Examples: Ferrous sulphate, Ferrous gluconate, Ferrous fumarate, Iron dextran (injectable)
Preparation of Ferrous Sulphate (FeSO₄·7H₂O):
- Prepared by dissolving iron in dilute sulphuric acid:
- Fe + H₂SO₄ → FeSO₄ + H₂↑
- Crystallised as pale green crystals (hydrated form).
- I.P. contains not less than 98% FeSO₄·7H₂O.
Properties: Green crystalline solid; effloresces in dry air; oxidises to ferric (brown) on exposure.
Uses of Iron:
- Treatment of iron-deficiency anaemia (commonest type)
- Prophylaxis in pregnancy, childhood, post-surgery
- Dose: 200 mg FeSO₄ (= 60 mg elemental iron) TDS
B. Cyanocobalamin (Vitamin B₁₂)
- Preparation: Produced by fermentation using Streptomyces griseus
- Uses: Treatment of pernicious anaemia (lack of intrinsic factor), megaloblastic anaemia, subacute combined degeneration of cord
- Administered IM when intrinsic factor is absent
C. Folic Acid (Vitamin B₉)
- Synthetic form of folate
- Uses: Treatment of megaloblastic anaemia, neural tube defect prophylaxis in pregnancy (400 mcg/day), antimetabolite toxicity reversal
Q.1(d) Explain nomenclature of heterocyclic compounds containing up to three rings with examples. (5 Marks)
Heterocyclic Compounds
Heterocyclic compounds are cyclic organic compounds in which at least one ring atom is a heteroatom (other than carbon) — most commonly N, O, or S.
Nomenclature Rules (Hantzsch-Widman System)
Prefixes indicate the heteroatom:
- Oxa- = Oxygen (O)
- Thia- = Sulfur (S)
- Aza- = Nitrogen (N)
Suffixes indicate ring size and saturation:
| Ring Size | Unsaturated (aromatic) | Saturated |
|---|---|---|
| 3-membered | -irene | -iridine |
| 4-membered | -ete | -etidine |
| 5-membered | -ole | -olidine |
| 6-membered | -ine | -inane |
One-Ring Heterocycles (Monocyclic)
| Name | Ring | Heteroatom | Example Drug |
|---|---|---|---|
| Pyrrole | 5-membered | 1 N | Atorvastatin (pyrrole ring) |
| Furan | 5-membered | 1 O | Ranitidine (furan ring) |
| Thiophene | 5-membered | 1 S | Clopidogrel |
| Pyridine | 6-membered | 1 N | Isoniazid, Niacin |
| Oxazole | 5-membered | N + O | — |
| Imidazole | 5-membered | 2 N | Metronidazole, Ketoconazole |
Two-Ring Heterocycles (Bicyclic/Fused)
| Name | System | Example Drug |
|---|---|---|
| Indole | Benzene + Pyrrole | Indomethacin, Serotonin |
| Benzimidazole | Benzene + Imidazole | Omeprazole, Mebendazole |
| Quinoline | Benzene + Pyridine | Chloroquine, Quinine |
| Benzofuran | Benzene + Furan | Amiodarone |
| Purine | Imidazole + Pyrimidine | Adenine, Caffeine |
Three-Ring Heterocycles (Tricyclic)
| Name | System | Example Drug |
|---|---|---|
| Acridine | Two benzene + Pyridine | Acridine dyes (antiseptics) |
| Phenothiazine | Two benzene + Thiazine | Chlorpromazine (antipsychotic) |
| Xanthene | Two benzene + Pyran | Fluorescein |
| Carbazole | Two benzene + Pyrrole | Carvedilol |
Q.1(e) Classify drugs acting on the central nervous system. Explain any two sedatives and hypnotics. (5 Marks)
Classification of CNS Drugs
- CNS Depressants
- General anaesthetics (thiopentone, halothane)
- Sedatives and hypnotics (benzodiazepines, barbiturates)
- Opioid analgesics (morphine, codeine)
- Antipsychotics / neuroleptics (chlorpromazine)
- Antidepressants (fluoxetine, amitriptyline)
- Antiepileptics (phenytoin, valproate)
- Anxiolytics (diazepam)
- CNS Stimulants
- Amphetamines, caffeine, methylphenidate
- Drugs for Neurodegenerative Disorders
- Anti-Parkinson's (levodopa, carbidopa)
- Anti-Alzheimer's (donepezil, rivastigmine)
Two Sedatives and Hypnotics
1. Diazepam (Benzodiazepine)
- Class: Benzodiazepine sedative-hypnotic
- Chemistry: 1,4-benzodiazepine derivative; chemical name: 7-chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one
- Mechanism: Enhances the effect of GABA at GABA-A receptors → increased Cl⁻ influx → neuronal hyperpolarisation → CNS depression
- Pharmacological Actions:
- Anxiolytic (anti-anxiety)
- Sedative and hypnotic (sleep-inducing)
- Muscle relaxant
- Anticonvulsant
- Uses: Anxiety disorders, insomnia, status epilepticus, alcohol withdrawal, pre-anaesthetic medication, muscle spasm
- Side effects: Drowsiness, ataxia, dependence, tolerance
- Dose: 2–10 mg orally
2. Phenobarbitone (Barbiturate)
- Class: Long-acting barbiturate
- Chemistry: 5-ethyl-5-phenylbarbituric acid; derived from barbituric acid (malonylurea)
- Mechanism: Acts on GABA-A receptor (at a different site from benzodiazepines) → prolongs Cl⁻ channel opening → CNS depression. At high doses, it can also block Na⁺ channels.
- Pharmacological Actions:
- Sedative (low doses), hypnotic (moderate doses), anaesthetic (high doses)
- Anticonvulsant
- Uses: Epilepsy (tonic-clonic and partial seizures), sedation, status epilepticus (IV), insomnia (less preferred now due to dependence)
- Side effects: Hangover effect, paradoxical excitement in children, tolerance, physical dependence, respiratory depression in overdose
- Dose: 30–120 mg at bedtime (hypnotic); 60–180 mg/day (anticonvulsant)
Q.1(f) Explain sympathomimetic agents with classification and examples. (5 Marks)
Sympathomimetic Agents
Sympathomimetic agents are drugs that mimic or stimulate the effects of the sympathetic nervous system (adrenergic system). They act by stimulating adrenergic receptors (α and β receptors) or by promoting the release/inhibiting reuptake of catecholamines.
Classification
A. Based on Mechanism of Action:
| Type | Mechanism | Example |
|---|---|---|
| Direct-acting | Directly stimulate α and/or β receptors | Adrenaline (Epinephrine), Noradrenaline, Salbutamol, Phenylephrine |
| Indirect-acting | Release noradrenaline from nerve terminals | Amphetamine, Tyramine |
| Mixed-acting | Both direct and indirect mechanisms | Ephedrine, Pseudoephedrine |
B. Based on Receptor Selectivity:
| Receptor | Effect | Drug Example |
|---|---|---|
| α₁ and α₂ | Vasoconstriction, mydriasis | Noradrenaline, Phenylephrine |
| β₁ | Increased heart rate and force | Dobutamine, Isoprenaline |
| β₂ | Bronchodilation, vasodilation | Salbutamol, Terbutaline |
| α + β | Multiple effects | Adrenaline (Epinephrine) |
Key Examples
1. Adrenaline (Epinephrine):
- Acts on α₁, α₂, β₁, β₂ receptors
- Uses: Anaphylaxis (drug of choice), cardiac arrest, acute bronchospasm, combined with local anaesthetics
- Given: SC/IM/IV; 0.5 mL of 1:1000 solution IM for anaphylaxis
2. Salbutamol (Albuterol):
- Selective β₂ agonist
- Uses: Bronchial asthma (first-line bronchodilator), COPD, premature labour
- Route: Inhaler (100–200 mcg), oral
3. Dopamine:
- At low doses: D₁ receptor → renal vasodilation
- At moderate doses: β₁ → cardiac stimulation
- At high doses: α₁ → vasoconstriction
- Uses: Cardiogenic shock, septic shock
Q.1(g) Discuss anti-arrhythmic drugs with classification and uses. (5 Marks)
Anti-Arrhythmic Drugs
Anti-arrhythmic drugs are used to treat cardiac arrhythmias (abnormal heart rhythms) by modifying the electrical activity of the heart.
Classification (Vaughan Williams Classification)
| Class | Mechanism | Examples | Uses |
|---|---|---|---|
| Class I — Sodium Channel Blockers | Block fast Na⁺ channels → slow conduction | ||
| Ia | Moderate Na⁺ block + K⁺ block; ↑ AP duration | Quinidine, Procainamide, Disopyramide | AF, VT, VF |
| Ib | Weak Na⁺ block; ↓ AP duration | Lignocaine (Lidocaine), Mexiletine, Phenytoin | VT (acute), digoxin-induced arrhythmias |
| Ic | Strong Na⁺ block; no effect on AP duration | Flecainide, Propafenone | AF, SVT (no structural heart disease) |
| Class II — Beta-blockers | Block β₁ receptors → ↓ HR, ↓ AV conduction | Propranolol, Metoprolol, Atenolol | SVT, AF rate control, post-MI arrhythmias |
| Class III — K⁺ Channel Blockers | Block K⁺ channels → ↑ AP duration and refractory period | Amiodarone, Sotalol, Ibutilide | AF, VT, VF (Amiodarone = broadest spectrum) |
| Class IV — Calcium Channel Blockers | Block L-type Ca²⁺ channels in SA/AV node | Verapamil, Diltiazem | SVT, AF rate control |
| Others | Various | Digoxin (↑ vagal tone), Adenosine (terminates SVT) | SVT, AF |
Summary of Uses
- Atrial fibrillation (AF): Amiodarone, Digoxin, Verapamil, β-blockers
- Ventricular tachycardia (VT): Lignocaine (acute), Amiodarone
- SVT (paroxysmal): Adenosine (drug of choice), Verapamil
- Post-MI prevention: Lidocaine, β-blockers
PART – II (10 × 3 = 30 Marks) — Attempt any TEN
Q.2(i) Define accuracy and precision with examples. (3 Marks)
Accuracy is the closeness of a measured value to the true (accepted) value. It indicates how correct a measurement is.
- Example: If the true content of paracetamol in a tablet is 500 mg and the assay gives 499 mg, the result is highly accurate.
Precision is the closeness of repeated measurements to each other, regardless of the true value. It indicates reproducibility.
- Example: Three successive assays give 490 mg, 491 mg, 490.5 mg — these are precise (consistent) but not accurate if the true value is 500 mg.
Difference:
| Accuracy | Precision | |
|---|---|---|
| Meaning | Nearness to true value | Repeatability of measurements |
| Errors | Systematic errors | Random errors |
| Requirement | Both needed for quality analysis | — |
A good analytical method must be both accurate and precise.
Q.2(ii) What is volumetric analysis? State its advantages. (3 Marks)
Volumetric analysis (titrimetry) is a quantitative analytical technique in which the volume of a standard solution (titrant) of known concentration required to completely react with the analyte is measured to determine the unknown concentration or amount of a substance.
Principle: At the equivalence point, the moles of titrant = moles of analyte (stoichiometrically).
Advantages:
- Rapid and simple — results obtained quickly
- Accurate and precise results when performed correctly
- Inexpensive — requires basic laboratory equipment (burette, pipette, flask)
- Applicable to a wide range of substances — acids, bases, oxidising/reducing agents, complexes
- Official method in pharmacopoeias (I.P., B.P., U.S.P.) for drug assay
- Suitable for routine quality control of pharmaceuticals
Q.2(iii) Explain limit test for sulphates briefly. (3 Marks)
Principle: Sulphate ions (SO₄²⁻) react with barium chloride (BaCl₂) in dilute hydrochloric acid (HCl) to form a white precipitate/turbidity of barium sulphate (BaSO₄).
Reaction:
SO₄²⁻ + BaCl₂ → BaSO₄↓ (white) + 2Cl⁻
Reagents: Dilute HCl, 25% BaCl₂ solution, standard sulphate solution (K₂SO₄ — 1 mL = 0.1 mg SO₄)
Procedure (I.P.):
- Dissolve the sample in 40 mL distilled water in a Nessler cylinder; add 2 mL dilute HCl.
- Add 5 mL of 25% BaCl₂ solution; mix and stand for 5 minutes.
- Prepare a standard similarly using the prescribed volume of standard sulphate solution.
- Compare opalescence transversely against a black background.
- Turbidity in the test ≤ turbidity in the standard → PASS.
Q.2(iv) Define complexometric titration with example. (3 Marks)
Complexometric titration is a type of volumetric analysis based on the formation of a stable, soluble complex (chelate) between a metal ion and a complexing agent (ligand). The endpoint is detected using a metal indicator.
Most Common Reagent: EDTA (Ethylenediaminetetraacetic acid) — a hexadentate ligand that forms 1:1 chelate with most metal ions.
Reaction:
M²⁺ + EDTA⁴⁻ → [M-EDTA]²⁻ (stable chelate)
Example — Assay of Calcium Gluconate (I.P.):
- Dissolve sample in buffer (pH 10)
- Add indicator Eriochrome Black T (EBT) — turns wine-red with Ca²⁺
- Titrate with 0.05 M EDTA
- At endpoint: free Ca²⁺ exhausted → indicator turns blue (pure)
Other examples:
- Assay of Zinc Sulphate (indicator: EBT, pH 10)
- Assay of Magnesium Sulphate (indicator: EBT)
- Calcium + Magnesium (water hardness estimation)
Indicator used: Eriochrome Black T (EBT), Calcon, Murexide
Q.2(v) Write a short note on antacids. (3 Marks)
Antacids are basic substances that neutralise excess gastric hydrochloric acid to relieve acidity, heartburn, and peptic ulcer symptoms.
Mechanism: Antacid (base) + HCl (gastric acid) → Salt + Water → ↑ gastric pH
Classification and Examples:
| Type | Example | Reaction |
|---|---|---|
| Sodium bicarbonate | NaHCO₃ | NaHCO₃ + HCl → NaCl + H₂O + CO₂↑ |
| Magnesium hydroxide | Milk of Magnesia | Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O |
| Aluminium hydroxide | Alu-gel | Al(OH)₃ + 3HCl → AlCl₃ + 3H₂O |
| Calcium carbonate | CaCO₃ | CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂↑ |
| Combination | Gelusil, Digene | Al(OH)₃ + Mg(OH)₂ |
Properties of an ideal antacid: Rapid onset, sustained action, non-absorbable, no acid rebound, no belching/flatulence, no interference with nutrient absorption.
Uses: Acidity, peptic ulcer, GERD, hyperacidity
Q.2(vi) Define cathartics with two examples. (3 Marks)
Cathartics (also called laxatives/purgatives) are agents that promote bowel evacuation by stimulating intestinal peristalsis, softening stools, or increasing bulk.
Classification:
- Stimulant cathartics — irritate intestinal mucosa → peristalsis
- Bulk-forming cathartics — absorb water → increase stool bulk
- Osmotic cathartics — retain water in intestine by osmosis
- Lubricant cathartics — lubricate intestinal walls
Two Examples:
1. Castor Oil (Oleum Ricini):
- Type: Stimulant cathartic
- Source: Seeds of Ricinus communis
- Mechanism: Hydrolysed in the intestine to ricinoleic acid, which irritates the intestinal mucosa → increased peristalsis → rapid evacuation
- Uses: Acute constipation, bowel preparation before surgery/X-ray, food poisoning
- Dose: 15–60 mL
2. Magnesium Sulphate (Epsom Salt — MgSO₄·7H₂O):
- Type: Osmotic cathartic (saline cathartic)
- Mechanism: Poorly absorbed saline → creates osmotic pressure in intestine → retains water → distends bowel → promotes defaecation
- Uses: Acute constipation, bowel cleansing, also used to treat magnesium deficiency
- Dose: 5–15 g orally in water
Q.2(vii) What are dental products? Give examples. (3 Marks)
Dental products are pharmaceutical and cosmetic preparations used for the care, hygiene, and treatment of teeth, gums, and oral cavity.
Classification and Examples:
| Category | Examples | Use |
|---|---|---|
| Dentifrices (Toothpastes/Powders) | Sodium fluoride, Calcium carbonate, Dicalcium phosphate | Cleaning teeth, preventing caries, polishing |
| Antiseptic mouthwashes | Chlorhexidine gluconate solution, Hydrogen peroxide (3%), Cetylpyridinium chloride | Gingivitis, oral hygiene, plaque control |
| Topical fluoride agents | Sodium fluoride gel (0.4%), Stannous fluoride | Fluoridation, preventing dental caries |
| Desensitising agents | Potassium nitrate, Strontium chloride | Sensitive dentine |
| Dental anaesthetics | Benzocaine gel, Lignocaine dental gel | Pain relief before procedures |
| Disclosing agents | Erythrosine (Red dye) | Reveals dental plaque |
Role of Fluoride in Dental Products:
- Fluoride converts susceptible hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂] to resistant fluorapatite [Ca₁₀(PO₄)₆F₂], making enamel resistant to acid dissolution and caries.
Q.2(viii) What are beta-blockers? Give two examples. (3 Marks)
Beta-blockers (β-adrenoceptor antagonists) are drugs that competitively block β-adrenergic receptors, thereby reducing the effects of catecholamines (adrenaline, noradrenaline) on the heart and other organs.
Pharmacological Effects (by blocking β₁):
- ↓ Heart rate (negative chronotropy)
- ↓ Force of myocardial contraction (negative inotropy)
- ↓ Blood pressure
- ↓ Cardiac output
- ↓ AV conduction velocity
- ↓ Renin secretion
Classification:
- Non-selective (β₁ + β₂): Propranolol, Sotalol
- Cardioselective (β₁ only): Atenolol, Metoprolol, Bisoprolol
- With vasodilatory action: Carvedilol (α + β blocker), Labetalol
Two Examples:
1. Propranolol:
- Non-selective β-blocker (β₁ + β₂)
- Uses: Hypertension, angina, arrhythmias, hyperthyroidism, migraine prophylaxis, anxiety (performance anxiety), portal hypertension
- Dose: 40–80 mg 2–3 times daily
- Contraindicated in asthma (β₂ blockade → bronchospasm)
2. Atenolol:
- Cardioselective β₁-blocker
- Uses: Hypertension (first-line), angina pectoris, post-MI, arrhythmias
- Advantage: Safer in diabetics and mild asthma (relative)
- Dose: 25–100 mg once daily
Q.2(ix) Write a note on hypoglycemic agents. (3 Marks)
Hypoglycemic agents (antidiabetic drugs) are agents that lower blood glucose levels in the management of diabetes mellitus.
Classification:
| Class | Examples | Mechanism |
|---|---|---|
| Insulin | Regular insulin, NPH insulin, Glargine | Increases glucose uptake, inhibits gluconeogenesis |
| Sulphonylureas (1st gen) | Tolbutamide, Chlorpropamide | Stimulate insulin secretion from β-cells (close K⁺-ATP channels) |
| Sulphonylureas (2nd gen) | Glibenclamide, Glipizide, Gliclazide | Same as above; more potent |
| Biguanides | Metformin | Decreases hepatic glucose production, improves peripheral insulin sensitivity |
| Meglitinides | Repaglinide, Nateglinide | Rapid, short-acting insulin secretagogues |
| Thiazolidinediones (TZDs) | Pioglitazone, Rosiglitazone | PPAR-γ agonists; improve insulin sensitivity |
| Alpha-glucosidase inhibitors | Acarbose, Voglibose | Delay carbohydrate absorption |
| DPP-4 Inhibitors | Sitagliptin, Vildagliptin | Increase incretin levels → stimulate insulin |
| SGLT-2 Inhibitors | Dapagliflozin, Empagliflozin | Inhibit renal glucose reabsorption → glucosuria |
| GLP-1 Agonists | Liraglutide, Exenatide | Stimulate insulin, inhibit glucagon |
Drug of choice: Metformin is the first-line oral drug for Type 2 DM.
Q.2(x) Classify anti-infective agents. (3 Marks)
Anti-infective agents are drugs used to treat infections caused by microorganisms (bacteria, fungi, viruses, parasites).
Classification:
A. Antibacterials (Antibiotics + Synthetic)
- Cell wall synthesis inhibitors: Penicillins, Cephalosporins, Vancomycin, Carbapenems
- Protein synthesis inhibitors:
- 30S: Aminoglycosides (Streptomycin), Tetracyclines
- 50S: Macrolides (Erythromycin), Chloramphenicol, Lincosamides
- DNA/RNA synthesis inhibitors: Fluoroquinolones (Ciprofloxacin), Rifampicin, Metronidazole
- Cell membrane disruptors: Polymyxin B, Colistin
- Antimetabolites: Sulfonamides (Sulfamethoxazole), Trimethoprim
B. Antifungal Agents
- Azoles: Fluconazole, Ketoconazole
- Polyenes: Amphotericin B, Nystatin
- Allylamines: Terbinafine
C. Antiviral Agents
- Antiherpes: Acyclovir, Valacyclovir
- Anti-HIV (ARVs): Zidovudine, Nevirapine, Tenofovir
- Anti-influenza: Oseltamivir, Zanamivir
- Anti-Hepatitis: Interferon, Sofosbuvir
D. Antiprotozoal Agents
- Antimalarials: Chloroquine, Quinine, Artemether
- Antiamoebics: Metronidazole, Diloxanide
E. Anthelmintics
- Mebendazole, Albendazole, Piperazine
Q.2(xi) What are sulfonamides? Give two examples. (3 Marks)
Sulfonamides are synthetic antibacterial drugs derived from sulfanilamide (para-aminobenzenesulfonamide). They were the first systemic antibacterial agents introduced into clinical medicine.
Chemistry: All sulfonamides contain the basic structure: H₂N-C₆H₄-SO₂-NH-R (para-amino group + sulfonamide group)
Mechanism of Action:
- Sulfonamides are PABA (para-aminobenzoic acid) analogues.
- Bacteria cannot absorb exogenous folic acid; they must synthesise it from PABA.
- Sulfonamides competitively inhibit dihydropteroate synthase → block bacterial folic acid synthesis → bacteriostatic effect.
- Human cells absorb preformed folic acid, so sulfonamides are selectively toxic to bacteria.
Two Examples:
1. Sulfamethoxazole (SMZ):
- Medium-acting sulfonamide
- Used in combination with trimethoprim (Co-trimoxazole) for UTIs, respiratory infections, Pneumocystis jirovecii pneumonia (PCP), typhoid
- Dose: 400 mg (as co-trimoxazole 480 mg BD)
2. Sulfadiazine:
- Used in combination with pyrimethamine for toxoplasmosis (especially cerebral toxoplasmosis in HIV patients)
- Also used topically as silver sulfadiazine cream for burn wound infections
- Used in treatment of meningococcal meningitis
PART – III (20 × 1 = 20 Marks) — Attempt ALL
| No. | Question | Answer |
|---|---|---|
| i. | Principle of limit test for chlorides | Chloride ions react with silver nitrate (AgNO₃) in dilute HNO₃ to form a white turbidity of silver chloride (AgCl), compared with a standard |
| ii. | Full form of I.P. | Indian Pharmacopoeia |
| iii. | One example of haematinic | Ferrous Sulphate (FeSO₄·7H₂O) |
| iv. | Indicator used in acid-base titration | Phenolphthalein (or Methyl Orange) |
| v. | Example of antacid | Aluminium Hydroxide [Al(OH)₃] |
| vi. | One topical agent | Calamine (Zinc carbonate + Zinc oxide) / Benzocaine cream |
| vii. | Example of sedative drug | Diazepam (Benzodiazepine) |
| viii. | One sympathomimetic drug | Adrenaline (Epinephrine) |
| ix. | Example of beta-blocker | Propranolol |
| x. | One anti-arrhythmic drug | Amiodarone (Class III) |
| xi. | Example of diuretic | Furosemide (Frusemide) |
| xii. | One hypoglycemic agent | Metformin (Biguanide) |
| xiii. | Example of NSAID | Ibuprofen (Propionic acid derivative) |
| xiv. | One antifungal drug | Fluconazole (Azole antifungal) |
| xv. | Example of antitubercular drug | Isoniazid (INH) |
| xvi. | One antiviral drug | Acyclovir (Antiherpes) |
| xvii. | Example of antimalarial drug | Chloroquine |
| xviii. | One antibiotic | Ampicillin (Penicillin group) |
| xix. | Example of anticancer drug | Cyclophosphamide (Alkylating agent) |
| xx. | One sulfonamide drug | Sulfamethoxazole |
All answers are aligned to the D. Pharmacy 1st Year Pharmaceutical Chemistry syllabus (I.P./B.P. standards). Part I answers are detailed (5 marks each), Part II are concise (3 marks each), and Part III are single-point recall answers (1 mark each).
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