Monophasic liquids – Syrups MCQs With Answer

Introduction: Monophasic liquids like syrups are clear, homogeneous solutions widely used in pharmacy for palatable drug delivery. A syrup typically contains a high sucrose concentration to provide sweetness, viscosity, and intrinsic preservative effect, alongside flavoring agents, colors, buffers, and optional preservatives (e.g., sodium benzoate, sorbic acid). B. Pharm students must master formulation principles, stability issues (crystallization, inversion, microbial growth), methods of preparation (with heat, without heat, percolation), and quality control (Brix, specific gravity, microbial limits). Knowledge of sugar-free vehicles (sorbitol, sucralose), co-solvents (glycerin, ethanol), and viscosity modifiers is essential for optimizing taste, safety, and shelf life. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What best defines a pharmaceutical syrup?

• Concentrated aqueous solution of sucrose or other sugars with or without medicament
• Suspension of insoluble drugs in water
• Hydroalcoholic solution with high alcohol content
• Emulsion of oil in water

Correct Answer: Concentrated aqueous solution of sucrose or other sugars with or without medicament

Q2. The sucrose concentration that generally renders simple syrup self‑preserving is approximately:

• 30% w/w
• 50% w/w
• 66.7% w/w
• 90% w/w

Correct Answer: 66.7% w/w

Q3. The primary reason high sucrose levels inhibit microbial growth in syrups is:

• Increase in pH
• Decrease in osmotic pressure
• Reduction of water activity due to high osmotic pressure
• Chemical toxicity of sucrose to microbes

Correct Answer: Reduction of water activity due to high osmotic pressure

Q4. Hydrolysis of sucrose in syrups (inversion) yields:

• Lactose and fructose
• Glucose and galactose
• Glucose and fructose
• Maltose and glucose

Correct Answer: Glucose and fructose

Q5. A key advantage of preparing syrups without heat (cold process) is:

• Faster dissolution of sucrose
• Prevention of sucrose inversion and protection of thermolabile/volatile ingredients
• Higher specific gravity
• Elimination of the need for preservation

Correct Answer: Prevention of sucrose inversion and protection of thermolabile/volatile ingredients

Q6. Which preservative is commonly used around 0.1% w/v in syrups?

• Sodium benzoate
• Calcium carbonate
• Magnesium stearate
• Sodium bicarbonate

Correct Answer: Sodium benzoate

Q7. Which additive most effectively minimizes crystallization of sucrose in stored syrups?

• Invert sugar
• Sodium chloride
• Citric acid
• Talc

Correct Answer: Invert sugar

Q8. Which is an example of a nonmedicated syrup used as a vehicle?

• Antihistamine syrup
• Cherry syrup
• Antitussive syrup
• Antipyretic syrup

Correct Answer: Cherry syrup

Q9. In syrups, glycerin primarily functions as a:

• Disintegrant
• Humectant and co‑solvent that aids preservation and viscosity
• Enteric coating agent
• Foaming agent

Correct Answer: Humectant and co‑solvent that aids preservation and viscosity

Q10. The approximate specific gravity of simple syrup is:

• 0.95
• 1.00
• 1.10
• 1.313

Correct Answer: 1.313

Q11. Which preparation method is preferred for syrups containing thermolabile drugs?

• Boiling the solution for extended time
• Percolation with heated menstruum
• Solution by agitation without heat (cold process)
• Dry heat dissolution

Correct Answer: Solution by agitation without heat (cold process)

Q12. Diluting a self‑preserving syrup below its critical sucrose concentration most likely leads to:

• Reduced sweetness only
• Increased crystallization
• Enhanced microbial growth
• Immediate phase separation

Correct Answer: Enhanced microbial growth

Q13. Syrup viscosity can be adjusted with which polymer(s)?

• Xanthan gum
• Hydroxypropyl methylcellulose (HPMC)
• Sodium carboxymethylcellulose (NaCMC)
• All of the above

Correct Answer: All of the above

Q14. Sucrose inversion in syrups is favored by:

• Neutral pH and low temperature
• Acidic pH and elevated temperature
• Alkaline pH and refrigeration
• High ionic strength and freezing

Correct Answer: Acidic pH and elevated temperature

Q15. A suitable sugar‑free sweetening vehicle for diabetic-friendly syrups is:

• Sodium chloride solution
• Sorbitol 70% solution
• Acacia mucilage
• Olive oil

Correct Answer: Sorbitol 70% solution

Q16. Which statement correctly differentiates elixirs from syrups?

• Elixirs are suspensions; syrups are emulsions
• Elixirs are clear, sweetened hydroalcoholic solutions; less sweet and less viscous than syrups
• Elixirs are oily solutions; syrups are dry powders
• Elixirs and syrups have identical compositions

Correct Answer: Elixirs are clear, sweetened hydroalcoholic solutions; less sweet and less viscous than syrups

Q17. Methylparaben and propylparaben in syrups serve as:

• Antioxidants
• Flavor enhancers
• Antimicrobial preservatives against molds and bacteria
• Color stabilizers

Correct Answer: Antimicrobial preservatives against molds and bacteria

Q18. Buffering a syrup is primarily done to:

• Increase sweetness
• Maintain pH to enhance stability of drug and sucrose (minimize hydrolysis/inversion)
• Reduce viscosity
• Improve color intensity

Correct Answer: Maintain pH to enhance stability of drug and sucrose (minimize hydrolysis/inversion)

Q19. Ethanol may be included in a syrup mainly to:

• Increase density only
• Act as co‑solvent to solubilize actives and aid preservation
• Neutralize acids
• Provide effervescence

Correct Answer: Act as co‑solvent to solubilize actives and aid preservation

Q20. A rapid in‑process method to check sugar concentration in syrups is:

• UV spectrophotometry
• Polarimetry
• Refractometry (Brix measurement)
• Potentiometry

Correct Answer: Refractometry (Brix measurement)

Q21. Which excipient helps reduce cap crystallization and “sticky neck” in syrup bottles?

• Lactose monohydrate
• Sorbitol
• Calcium phosphate
• Titanium dioxide

Correct Answer: Sorbitol

Q22. Simple syrup exhibits a degree of self‑preservation mainly because:

• It contains high levels of ethanol
• Its high sucrose lowers water activity below microbial growth threshold
• It is sterile
• It contains strong acids

Correct Answer: Its high sucrose lowers water activity below microbial growth threshold

Q23. Crystals appear in a stored syrup. The most appropriate immediate corrective action is to:

• Add coloring agents
• Warm gently to dissolve crystals and adjust to correct sucrose concentration
• Add sodium chloride
• Freeze the syrup

Correct Answer: Warm gently to dissolve crystals and adjust to correct sucrose concentration

Q24. A common strategy to improve pediatric palatability of syrups is to:

• Increase viscosity to maximum
• Use suitable flavors and colors compatible with the API
• Raise pH above 9
• Eliminate sweeteners

Correct Answer: Use suitable flavors and colors compatible with the API

Q25. Which test is routinely used to assess microbial quality of syrups?

• High-performance liquid chromatography (HPLC)
• Total aerobic microbial count (plate count)
• Refractometry
• Polarography

Correct Answer: Total aerobic microbial count (plate count)

Q26. During percolation-based syrup preparation, clarity is best ensured by:

• Decantation only
• Filtration through appropriate filter media
• Standing overnight
• Adding talc as suspending agent

Correct Answer: Filtration through appropriate filter media

Q27. The approximate Brix value corresponding to simple syrup is:

• 20° Brix
• 40° Brix
• 65° Brix
• 85° Brix

Correct Answer: 65° Brix

Q28. Which preservative is most effective for syrups at acidic pH and less effective above pH 6.5?

• Potassium sorbate
• EDTA
• Thiourea
• Sodium carbonate

Correct Answer: Potassium sorbate

Q29. Which statement about medicated versus nonmedicated syrups is accurate?

• Both are sterile injections
• Nonmedicated syrups serve as flavored vehicles; medicated syrups contain active drugs
• Nonmedicated syrups are emulsions; medicated are suspensions
• Only medicated syrups require preservation

Correct Answer: Nonmedicated syrups serve as flavored vehicles; medicated syrups contain active drugs

Q30. The demulcent action relevant to syrups refers to their ability to:

• Increase gastric acidity
• Enhance drug volatility
• Coat and soothe mucous membranes due to high viscosity
• Induce effervescence

Correct Answer: Coat and soothe mucous membranes due to high viscosity

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