Effervescent powders – composition and method of preparation MCQs With Answer

Effervescent powders – composition and method of preparation MCQs With Answer

Effervescent powders are designed for rapid disintegration and delivery of active pharmaceutical ingredients using acid–carbonate reactions to generate CO2. Key components include an acid (citric, tartaric, fumaric), an alkali carbonate/bicarbonate (sodium bicarbonate), diluents, sweeteners, flavoring agents, binders, and moisture scavengers. Understanding formulation stoichiometry, moisture control, granulation techniques (dry mixing, wet granulation, fusion), stability testing, and appropriate packaging (dry, airtight) is critical for B.Pharm students. This topic covers materials selection, manufacturing challenges, analytical tests and quality control parameters specific to effervescent systems. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary chemical reaction responsible for effervescence in effervescent powders?

• Neutralization between an acid and an alcohol
• Oxidation of carbonate by oxygen
• Acid–carbonate reaction producing carbon dioxide
• Hydrolysis of ester bonds releasing CO2

Correct Answer: Acid–carbonate reaction producing carbon dioxide

Q2. Which acid pair is most commonly used in effervescent formulations due to balanced solubility and reactivity?

• Citric acid and fumaric acid
• Citric acid and tartaric acid
• Fumaric acid and benzoic acid
• Maleic acid and sorbic acid

Correct Answer: Citric acid and tartaric acid

Q3. Which alkaline component is most widely used in effervescent powders to generate CO2?

• Sodium chloride
• Sodium bicarbonate
• Calcium carbonate
• Magnesium sulfate

Correct Answer: Sodium bicarbonate

Q4. What is the main purpose of adding moisture scavengers (desiccants) in effervescent formulations?

• To improve taste masking
• To catalyze effervescence
• To reduce water content and prevent premature reaction
• To increase solubility of the active drug

Correct Answer: To reduce water content and prevent premature reaction

Q5. Which of the following is a common method for preparing effervescent powders to minimize moisture exposure?

• Wet granulation using aqueous binders
• Dry mixing with fusion method
• Supercritical CO2 granulation
• Lipophilic coating in organic solvent

Correct Answer: Dry mixing with fusion method

Q6. In the fusion method for effervescent granular preparation, what is typically heated to create granules?

• Active pharmaceutical ingredient beyond its melting point
• Sugar-based binders to form a molten syrup that agglomerates particles
• Acid and base to allow controlled reaction
• Desiccant to vaporize moisture

Correct Answer: Sugar-based binders to form a molten syrup that agglomerates particles

Q7. Which excipient is primarily used for taste-masking and improving palatability in effervescent powders?

• Avicel 102 (microcrystalline cellulose)
• Sucrose or sorbitol as sweeteners
• Talc as glidant
• Magnesium stearate as lubricant

Correct Answer: Sucrose or sorbitol as sweeteners

Q8. What is the role of effervescent granules’ particle size control in product performance?

• It only affects color intensity
• It influences dissolution time, effervescence rate, and mouthfeel
• It determines the melting point of the formulation
• It prevents chemical reaction between API and excipients

Correct Answer: It influences dissolution time, effervescence rate, and mouthfeel

Q9. Which packaging is most suitable to maintain stability of effervescent powders?

• Perforated plastic pouches
• High-barrier, airtight containers with desiccant
• Paper sachets without linings
• Mesh bags for ventilation

Correct Answer: High-barrier, airtight containers with desiccant

Q10. Which test is critical for assessing the performance of an effervescent powder product?

• Disintegration time in 0.1 N HCl only
• Effervescence time and completeness of CO2 evolution in specified medium
• Viscosity measurement at 25°C
• Tensile strength of compressed tablets

Correct Answer: Effervescence time and completeness of CO2 evolution in specified medium

Q11. Why are effervescent powders more sensitive to moisture than conventional powders?

• They contain volatile oils that evaporate
• They include reactive acid and carbonate that react on moisture contact
• They are heavier and absorb more water by weight
• Their particle surfaces are hydrophobic

Correct Answer: They include reactive acid and carbonate that react on moisture contact

Q12. Which analytical parameter helps measure moisture content in effervescent powders?

• TLC (thin layer chromatography)
• Loss on drying (LOD) or Karl Fischer titration
• pH-meter reading of solid powder
• UV absorbance at 260 nm

Correct Answer: Loss on drying (LOD) or Karl Fischer titration

Q13. In stoichiometric formulation of effervescent systems, why is an excess of carbonate sometimes used?

• To provide a sweeter taste
• To ensure complete neutralization and sustained effervescence in variable conditions
• To accelerate moisture uptake
• To increase tablet hardness

Correct Answer: To ensure complete neutralization and sustained effervescence in variable conditions

Q14. Which binder is commonly used in non-aqueous wet granulation of effervescent powders to avoid premature reaction?

• Water-based PVP solution
• Isopropyl alcohol or ethanol solution of PVP
• Glycerin in water
• Acetic acid solution

Correct Answer: Isopropyl alcohol or ethanol solution of PVP

Q15. Which excipient can act as an anti-caking agent and improve flow in effervescent formulations?

• Sodium lauryl sulfate
• Colloidal silicon dioxide (aerosil)
• Magnesium oxide
• Polyethylene glycol 4000

Correct Answer: Colloidal silicon dioxide (aerosil)

Q16. Which factor most strongly affects the effervescence rate of an effervescent powder?

• Ambient light intensity
• Particle surface area and solubility of reactants
• Color of the powder
• Molecular weight of the flavoring agent

Correct Answer: Particle surface area and solubility of reactants

Q17. What is the main disadvantage of using fumaric acid alone as the acid component in effervescent formulations?

• Too high aqueous solubility causing instant reaction
• Low solubility and higher acidity causing slower effervescence
• It reacts with desiccants to form salts
• It produces an unpleasant odor

Correct Answer: Low solubility and higher acidity causing slower effervescence

Q18. Why is sorbitol often used as a diluent in effervescent powders compared to lactose?

• Sorbitol is more hygroscopic than lactose
• Sorbitol has sweetening properties and better mouthfeel with lower reactivity
• Lactose forms complexes with citric acid
• Sorbitol increases the melting point markedly

Correct Answer: Sorbitol has sweetening properties and better mouthfeel with lower reactivity

Q19. Which lubricant should be used cautiously in effervescent granules because it can retard dissolution if overused?

• Magnesium stearate
• Hydroxypropyl methylcellulose (HPMC)
• Sucrose
• Citric acid

Correct Answer: Magnesium stearate

Q20. For stability testing of effervescent powders, which accelerated condition is most relevant to evaluate moisture sensitivity?

• High temperature and high humidity (e.g., 40°C/75% RH)
• Freezing at -20°C
• Exposure to UV light only
• Low oxygen environment

Correct Answer: High temperature and high humidity (e.g., 40°C/75% RH)

Q21. Which of the following is true regarding the pH of the solution after effervescence for buffered formulations?

• pH is always neutral (7.0) regardless of components
• Final pH depends on the acid–base ratio and buffer components used
• pH increases to >10 due to carbonate excess
• pH cannot be controlled in effervescent systems

Correct Answer: Final pH depends on the acid–base ratio and buffer components used

Q22. When converting an effervescent powder formulation to an effervescent tablet, which factor requires special attention?

• Compression force and dwell time to prevent premature reaction and maintain porosity
• Color matching with powder
• Reducing API potency by half
• Using aqueous coatings to enhance gloss

Correct Answer: Compression force and dwell time to prevent premature reaction and maintain porosity

Q23. Which flavoring strategy helps mask acidity and improve patient acceptability in effervescents?

• Use of strong mint oils only
• Balance sweeteners and acidic flavors; incorporate citric/tartaric taste modulators
• Elimination of sweeteners to reduce interactions
• Use of bitter agents to counteract acidity

Correct Answer: Balance sweeteners and acidic flavors; incorporate citric/tartaric taste modulators

Q24. Which compatibility issue is most critical in effervescent formulations containing APIs sensitive to low pH?

• API may oxidize with carbonate
• API may degrade in acidic microenvironments produced before dissolution
• API becomes volatile at room temperature
• API will chelate with magnesium stearate

Correct Answer: API may degrade in acidic microenvironments produced before dissolution

Q25. Which manufacturing control is essential to prevent caking and ensure free-flowing effervescent powder?

• Increasing water content to 10%
• Controlled humidity, adequate drying, and use of anti-caking agents
• Adding more acid to neutralize moisture
• Using open-air storage during production

Correct Answer: Controlled humidity, adequate drying, and use of anti-caking agents

Q26. What is the effect of excessive compression on an effervescent tablet produced from effervescent powder?

• Improved effervescence due to more intimate contact
• Reduced porosity leading to slower dissolution and poor effervescence
• Increased moisture resistance
• Enhanced flavor release

Correct Answer: Reduced porosity leading to slower dissolution and poor effervescence

Q27. In assessing effervescent powder quality, which assay is commonly performed?

• Assay of API content and assay of total CO2 potential or neutralization capacity
• Assay of heavy metals only
• Assay of microbial load exclusively
• Assay of particle color index

Correct Answer: Assay of API content and assay of total CO2 potential or neutralization capacity

Q28. Which excipient can act both as a diluent and to improve mouthfeel while being minimally reactive with acid/base pairs?

• Sodium chloride
• Sorbitol or mannitol
• Calcium carbonate
• Citric acid

Correct Answer: Sorbitol or mannitol

Q29. How does increasing the ratio of tartaric acid relative to citric acid affect effervescence?

• It makes the reaction extremely slow and incomplete
• It typically speeds up initial reaction due to higher acidity but may alter taste
• It prevents CO2 formation entirely
• It increases the melting point of the mixture

Correct Answer: It typically speeds up initial reaction due to higher acidity but may alter taste

Q30. What is a key regulatory consideration when marketing effervescent powder formulations?

• Labeling must include directions for dissolution volume, storage (keep dry), and excipient warnings
• There are no specific requirements beyond normal tablets
• They must be sold only to hospitals
• They are exempt from stability testing

Correct Answer: Labeling must include directions for dissolution volume, storage (keep dry), and excipient warnings

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