Caffeine – industrial production and use explores the chemistry, manufacturing processes and pharmaceutical applications of this widely used methylxanthine. For B.Pharm students, understanding natural extraction (coffee, tea), industrial decaffeination (solvent, supercritical CO2, Swiss Water), and synthetic routes complements knowledge of pharmacology, ADME, toxicity, formulation and regulatory quality control. Key analytical keywords include HPLC, UV spectroscopy, TLC, residual solvents and assay limits. Industrial challenges such as purification, process safety, environmental impact and scale-up are essential for production and product development. This introduction links fundamental chemistry to practical manufacturing and therapeutic contexts. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the molecular formula of caffeine?
- C7H8N4O2
- C8H10N4O2
- C9H12N4O2
- C8H8N4O3
Correct Answer: C8H10N4O2
Q2. Which class of compounds does caffeine belong to?
- Alkaloids (methylxanthines)
- Flavonoids
- Terpenoids
- Saponins
Correct Answer: Alkaloids (methylxanthines)
Q3. Which industrial method uses CO2 above its critical point to extract caffeine?
- Steam distillation
- Supercritical CO2 extraction
- Liquid-liquid extraction with hexane
- Cold maceration
Correct Answer: Supercritical CO2 extraction
Q4. Which solvent is commonly used in coffee decaffeination and later scrutinized for residue limits?
- Ethyl acetate
- Methanol
- Chloroform
- Acetone
Correct Answer: Ethyl acetate
Q5. The Swiss Water Process for decaffeination primarily relies on which principle?
- Use of organic solvents to dissolve caffeine
- Water-soluble selective adsorption and diffusion with activated carbon
- Supercritical fluid extraction with ethanol modifier
- Enzymatic degradation of caffeine
Correct Answer: Water-soluble selective adsorption and diffusion with activated carbon
Q6. In pharmaceutical analysis, which technique is most commonly used for quantitative determination of caffeine in formulations?
- Paper chromatography
- HPLC with UV detection
- NMR spectroscopy as routine QC
- Flame photometry
Correct Answer: HPLC with UV detection
Q7. At approximately which UV wavelength is caffeine typically detected by UV-visible spectroscopy/HPLC-UV?
- 210 nm
- 254 nm
- 272–275 nm
- 340 nm
Correct Answer: 272–275 nm
Q8. Which liver enzyme mainly metabolizes caffeine in humans?
- CYP2D6
- CYP3A4
- CYP1A2
- MAO-A
Correct Answer: CYP1A2
Q9. Industrial synthetic production of caffeine often uses which starting material or intermediate?
- Nicotine
- Xanthine derivatives (e.g., theobromine or theophylline)
- Sucrose
- Quinine
Correct Answer: Xanthine derivatives (e.g., theobromine or theophylline)
Q10. Which property of caffeine influences its formulation into oral tablets?
- High lipid solubility and insolubility in water
- Low melting point below room temperature
- Moderate water solubility and crystalline stability
- High hygroscopicity making it unsuitable for tablets
Correct Answer: Moderate water solubility and crystalline stability
Q11. What is a common pharmaceutical use of caffeine salts like caffeine citrate?
- Treatment of neonatal apnea
- Antibiotic adjunct therapy
- Insulin sensitizer
- Topical anesthetic
Correct Answer: Treatment of neonatal apnea
Q12. Which regulatory concern is important during industrial caffeine extraction from natural sources?
- Residual solvent limits and pesticide residues
- Presence of heavy metals only in synthetic caffeine
- Radioactive contamination from decaffeination
- Monoclonal antibody contamination
Correct Answer: Residual solvent limits and pesticide residues
Q13. Which of the following is a major environmental advantage of supercritical CO2 extraction compared with solvent-based methods?
- Higher residual organic solvent in final product
- Lower energy consumption always
- Reduced solvent residues and easier solvent recovery
- Production of toxic by-products
Correct Answer: Reduced solvent residues and easier solvent recovery
Q14. Which quality control test specifically assesses caffeine purity in a bulk drug supply?
- Microbial limit test only
- Assay by validated HPLC method and related substances
- Loss on drying only
- Disintegration test
Correct Answer: Assay by validated HPLC method and related substances
Q15. Which pharmacological mechanism best explains caffeine’s stimulant effect?
- Beta-adrenergic receptor agonism
- Adenosine receptor antagonism
- GABA-A receptor agonism
- Cholinesterase inhibition
Correct Answer: Adenosine receptor antagonism
Q16. Typical elimination half-life of caffeine in healthy adults is closest to:
- 30 minutes
- 3–7 hours
- 24–48 hours
- One week
Correct Answer: 3–7 hours
Q17. Which excipient consideration is important when formulating caffeine tablets to prevent migration or segregation during manufacturing?
- Use of nonionic surfactants only
- Particle size matching and appropriate glidants
- Ensure extreme hydrophobicity of all excipients
- Avoid any fillers to keep tablets pure caffeine
Correct Answer: Particle size matching and appropriate glidants
Q18. Which adverse effect is most commonly associated with caffeine overdose?
- Bradycardia and hypotension
- Insomnia, tachycardia, tremors and anxiety
- Severe hepatic necrosis
- Profound hypoglycemia
Correct Answer: Insomnia, tachycardia, tremors and anxiety
Q19. For analytical method validation of caffeine assay by HPLC, which parameter is essential?
- Only visual color comparison
- Specificity, linearity, accuracy, precision and robustness
- Only retention time stability
- Only final product taste
Correct Answer: Specificity, linearity, accuracy, precision and robustness
Q20. Which pair of decaffeination methods uses solvent and non-solvent approaches respectively?
- Ethyl acetate extraction and supercritical CO2 extraction
- Swiss Water Process and solvent-based extraction
- Supercritical CO2 extraction and steam distillation
- Enzymatic hydrolysis and fermentation
Correct Answer: Swiss Water Process and solvent-based extraction
Q21. Which analytical technique can rapidly confirm presence of caffeine but is less quantitative than HPLC?
- TLC with specific visualization
- Karl Fischer titration
- Mohr titration
- Atomic absorption spectroscopy
Correct Answer: TLC with specific visualization
Q22. In large-scale caffeine manufacture, what is a common downstream purification step after extraction or synthesis?
- Direct tablet compression without purification
- Recrystallization and activated carbon treatment
- Spray drying into aerosols for inhalation
- Lyophilization of crude oil
Correct Answer: Recrystallization and activated carbon treatment
Q23. Which statement about caffeine solubility is correct?
- Caffeine is insoluble in water at room temperature
- Caffeine has moderate water solubility which increases with temperature
- Caffeine is highly lipid soluble and insoluble in polar solvents
- Caffeine decomposes immediately in aqueous media
Correct Answer: Caffeine has moderate water solubility which increases with temperature
Q24. Which population requires dose adjustment or caution due to slower caffeine metabolism?
- Healthy young adults only
- Pregnant women and neonates
- Smokers (increased clearance)
- Individuals taking CYP1A2 inducers
Correct Answer: Pregnant women and neonates
Q25. What is a primary analytical concern when testing decaffeinated coffee for compliance?
- Determining caffeine content to ensure it meets regulatory limits
- Measuring pH only
- Testing for lactose contamination
- Measuring only moisture content
Correct Answer: Determining caffeine content to ensure it meets regulatory limits
Q26. Which impurity profile is typically monitored in pharmaceutical-grade caffeine?
- Only microbial contaminants
- Related xanthine alkaloids and residual solvents
- Presence of penicillin residues
- High levels of polysaccharides
Correct Answer: Related xanthine alkaloids and residual solvents
Q27. Why is particle size distribution important for powdered caffeine used in inhalation formulations?
- It controls color and odor only
- It influences aerodynamic behavior and dose uniformity
- Particle size has no effect for inhalation delivery
- Smaller particles always increase stability against moisture
Correct Answer: It influences aerodynamic behavior and dose uniformity
Q28. Which process parameter is critical during supercritical CO2 extraction to maximize caffeine solubility?
- Magnetic field strength
- Pressure and temperature control
- Light exposure duration
- pH adjustment to 12
Correct Answer: Pressure and temperature control
Q29. In combined analgesic preparations, caffeine is added primarily to:
- Cause sedation and reduce side effects
- Potentiate analgesic effect and improve absorption
- Act as a preservative
- Provide antibacterial activity
Correct Answer: Potentiate analgesic effect and improve absorption
Q30. Which storage condition is most appropriate for bulk pharmaceutical caffeine to maintain stability?
- High humidity, room temperature with light exposure
- Cool, dry place protected from light in airtight containers
- Open containers in direct sunlight
- Store dissolved in water at 40°C
Correct Answer: Cool, dry place protected from light in airtight containers
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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