The GPAT is one of the most competitive exams for pharmacy graduates in India. In this article, we provide the GPAT 2026 Question Paper with Answers along with clear explanations to help aspirants understand the concepts and evaluate their performance.
This answer key covers questions from multiple subjects including pharmaceutics, pharmacology, pharmaceutical analysis, medicinal chemistry, pharmacognosy, and biotechnology.
GPAT 2026 Question Paper – Answers and Explanations
Q1. McCabe–Thiele method is primarily used to determine
✅ Answer: D. Number of theoretical plates in distillation
Explanation:
The McCabe–Thiele Method is a graphical method used in binary distillation to determine the number of theoretical plates required in a distillation column for a desired separation.
Q2. If the pKa of phenobarbitone is 3.4, what fraction of drug would be ionized at pH 4.4
✅ Answer: D. 0.90
Explanation:
The degree of ionization of weak acids is determined using the Henderson–Hasselbalch Equation.
Here pH − pKa = 1, so about 90% of the drug exists in ionized form.
✅ Answer: A. Reduce oxidation of drug
Explanation:
Nitrogen flushing replaces oxygen in the ampoule headspace and prevents oxidation of oxygen-sensitive drugs, thereby improving stability.
Q4. Quantitative value for identification of leaf drugs that does not remain constant with plant age
✅ Answer: D. Stomatal number
Explanation:
Parameters such as stomatal index, vein-islet number, and vein termination number remain constant, whereas stomatal number varies with environmental conditions and plant age.
Q5. Indicator used in EDTA titration of calcium and magnesium
✅ Answer: C. Eriochrome Black T
Explanation:
Ethylenediaminetetraacetic acid forms complexes with metal ions.
The indicator Eriochrome Black T changes color from wine red to blue at the end point.
Q6. In-process tablet thickness variation is mainly influenced by
✅ Answer: C. Compression force
Explanation:
Tablet thickness mainly depends on the compression force applied during tablet compression. Greater compression reduces tablet thickness due to higher compaction.
Q7. Taxol is primarily semi-synthesized from
✅ Answer: A. 10-deacetylbaccatin III
Explanation:
The anticancer drug Paclitaxel is semi-synthesized from 10-Deacetylbaccatin III, obtained from leaves of Taxus baccata.
Q8. Quinoline containing local anesthetic
✅ Answer: D. Dibucaine
Explanation:
Dibucaine (cinchocaine) contains a quinoline ring system, unlike other local anesthetics such as benzocaine or tetracaine.
Q9. Crop rotation, composting and biological pest control represent
✅ Answer: A. Integrated farming
Explanation:
The Integrated Farming System combines environmentally friendly agricultural practices to improve sustainability and reduce chemical inputs.
Q10. Gaseous sterilant not suitable for fumigation of rooms due to explosive property
✅ Answer: D. Ethylene oxide
Explanation:
Ethylene oxide is highly flammable and explosive when mixed with air, so it is unsuitable for room fumigation.
Q11. Relationship between pH, pKa and ionization
✅ Answer: B. Henderson–Hasselbalch equation
Explanation:
This equation relates environmental pH, drug pKa, and degree of ionization, helping predict drug absorption.
Q12. Ginkgo biloba should be avoided with
✅ Answer: C. Anticoagulants
Explanation:
Ginkgo biloba has antiplatelet activity and may increase bleeding risk when combined with Anticoagulants.
Q13. Laminar airflow cabinets provide which class of clean air
✅ Answer: C. Class 100
Explanation:
Laminar Air Flow Cabinet provides Class 100 clean air using HEPA filtration for aseptic pharmaceutical processing.
Q14. Constant region types of immunoglobulin light chain
✅ Answer: C. Kappa (κ) and Lambda (λ)
Explanation:
In Immunoglobulin, the light chains are classified into κ (kappa) and λ (lambda) types based on their constant region amino acid sequences.
Q15. Electron-withdrawing groups on phenothiazine enhance activity by
✅ Answer: C. Increasing dopamine receptor binding
Explanation:
Electron-withdrawing substituents at position-2 of Phenothiazines increase binding affinity to dopamine receptors, improving antipsychotic potency.
Q16. Internal diameter of glass tube in arsenic limit test apparatus
✅ Answer: D. 6.5 mm
Explanation:
In the Limit Test for Arsenic, the apparatus requires a glass tube with an internal diameter of 6.5 mm for proper gas flow and color development.
Q17. Active metabolite of acyclovir that binds DNA polymerase
✅ Answer: C. Acyclovir triphosphate; phosphorylation
Explanation:
Acyclovir is converted to acyclovir triphosphate through phosphorylation. This active metabolite inhibits viral DNA polymerase and stops viral DNA synthesis.
Q18. If emission intensity doubles when concentration doubles
✅ Answer: C. Linear proportionality
Explanation:
When signal intensity increases proportionally with concentration, the relationship follows linear proportionality, forming the basis of analytical calibration curves.
Q19. Lipophilic substituents on benzodiazepines enhance
✅ Answer: B. CNS penetration
Explanation:
In Benzodiazepines, lipophilic substituents increase blood–brain barrier penetration, improving central nervous system activity.
Q20. Best purification method for naphthalene
✅ Answer: A. Sublimation
Explanation:
Naphthalene easily sublimes, so purification is best achieved by sublimation, where the solid directly converts to vapor and re-crystallizes as pure crystals.
Q21. WHO recommends chromatographic techniques in herbal medicines mainly for
✅ Answer: D. Fingerprint profiling
Explanation:
The World Health Organization recommends chromatographic fingerprinting to ensure quality control, identification of marker compounds, and detection of adulteration in herbal drugs.
Q22. Mechanism of action of acarbose
✅ Answer: D. α-glucosidase inhibition
Explanation:
Acarbose inhibits intestinal α-glucosidase enzymes, delaying carbohydrate digestion and reducing post-meal blood glucose levels.
Q23. Iodine solubility in water
✅ Answer: B. 400
Explanation:
Iodine is sparingly soluble in water (approximately 1 part in 400 parts of water). Solubility increases when potassium iodide is added.
Q24. Most common buffer in ophthalmic preparations
✅ Answer: D. Phosphate buffer
Explanation:
Phosphate buffer is commonly used because its pH range closely matches the physiological pH of tears (~7.4).
Q25. Tube dilution test with stainless steel cylinders is used to determine
✅ Answer: C. Minimum bactericidal concentration
Explanation:
This method determines the Minimum Bactericidal Concentration, which is the lowest concentration of an antimicrobial agent that kills bacteria.