Butamben MCQs With Answer

Butamben MCQs With Answer

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Butamben MCQs With Answer — this focused introduction helps B. Pharm students deepen understanding of butamben, an ester-type local anesthetic derived from p-aminobenzoic acid. Topics covered include chemical structure, mechanism of action, ionization behavior, metabolism by plasma esterases, PABA-related hypersensitivity, formulation challenges (poor water solubility, stability, and packaging), and analytical methods for assay and dissolution. Emphasis is placed on pharmacokinetics, compatibility with excipients and preservatives, and strategies to enhance topical penetration and shelf life. These concise, high-yield MCQs target both theoretical concepts and practical formulation considerations relevant to pharmacy practice and research. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary chemical classification of butamben?

  • An amide-type local anesthetic
  • An ester-type local anesthetic
  • A ketone analgesic
  • A tertiary amine opioid

Correct Answer: An ester-type local anesthetic

Q2. Which structural feature defines butamben?

  • Aromatic ring linked to an amide and a tertiary amine
  • Para-aminobenzoate ester (butyl 4-aminobenzoate)
  • Phenol ether with a quaternary ammonium
  • A benzodiazepine core

Correct Answer: Para-aminobenzoate ester (butyl 4-aminobenzoate)

Q3. What is the main mechanism of action of butamben as a local anesthetic?

  • Inhibition of cyclooxygenase enzymes
  • Blockade of voltage-gated sodium channels in nerve membranes
  • Activation of GABA receptors
  • Competitive antagonism at NMDA receptors

Correct Answer: Blockade of voltage-gated sodium channels in nerve membranes

Q4. How does the aniline-type amino group influence butamben’s ionization at physiological pH?

  • It is highly protonated and water soluble at pH 7.4
  • It remains largely unionized (weakly basic aniline), increasing lipophilicity
  • It forms a permanent positive charge regardless of pH
  • It becomes negatively charged and cannot cross membranes

Correct Answer: It remains largely unionized (weakly basic aniline), increasing lipophilicity

Q5. Which metabolic pathway predominantly clears butamben from tissues/plasma?

  • Hepatic cytochrome P450 oxidation
  • Conjugation with glucuronic acid
  • Hydrolysis by plasma and tissue esterases producing PABA derivatives
  • Renal excretion unchanged due to high water solubility

Correct Answer: Hydrolysis by plasma and tissue esterases producing PABA derivatives

Q6. Which adverse reaction is particularly associated with ester-type anesthetics like butamben?

  • Hepatotoxicity due to NAPQI formation
  • PABA-mediated allergic reactions
  • Serotonin syndrome
  • Renal tubular necrosis

Correct Answer: PABA-mediated allergic reactions

Q7. Compared with tertiary-amine local anesthetics, butamben typically has which onset and duration profile?

  • Very rapid onset and extremely short duration
  • Slower onset but relatively prolonged local effect due to unionized form and lipophilicity
  • Immediate systemic action with no local effect
  • Long onset and no clinically useful duration

Correct Answer: Slower onset but relatively prolonged local effect due to unionized form and lipophilicity

Q8. What formulation challenge is most associated with butamben?

  • Excessive water solubility causing leakage
  • Poor aqueous solubility requiring co-solvents or emulsions
  • Instability to dry heat sterilization only
  • Strong buffering needs to maintain a basic pH of 10

Correct Answer: Poor aqueous solubility requiring co-solvents or emulsions

Q9. Which excipient strategy is commonly used to enhance topical penetration of butamben?

  • Addition of PABA to increase lipophilicity
  • Use of penetration enhancers like propylene glycol or ethanol
  • Inclusion of strong acids to protonate butamben
  • Adding surfactants that form micelles preventing skin uptake

Correct Answer: Use of penetration enhancers like propylene glycol or ethanol

Q10. Why is pH control important in butamben liquid topical formulations?

  • To prevent oxidation to active metabolites
  • To minimize acid-catalyzed ester hydrolysis and maintain stability
  • To ensure complete protonation for renal clearance
  • To enable formation of insoluble salts for sustained release

Correct Answer: To minimize acid-catalyzed ester hydrolysis and maintain stability

Q11. Which packaging consideration is most relevant to preserve butamben stability?

  • Use of clear glass to allow UV sterilization
  • Opaque or amber containers to limit light-accelerated degradation
  • Permeable plastic that allows oxygen ingress
  • Aluminum blister that reacts with esters

Correct Answer: Opaque or amber containers to limit light-accelerated degradation

Q12. Which analytical method is most appropriate for quantitative assay of butamben in formulations?

  • Colorimetric titration with iodine
  • Reverse-phase HPLC with UV detection
  • Thermogravimetric analysis
  • Polarimetry to measure optical rotation

Correct Answer: Reverse-phase HPLC with UV detection

Q13. What is a reliable sample preparation solvent for HPLC assay of butamben from creams?

  • Pure water only
  • Methanol or methanol–water mixtures to extract lipophilic ester
  • Concentrated sulfuric acid
  • Hexane exclusively

Correct Answer: Methanol or methanol–water mixtures to extract lipophilic ester

Q14. In forced-degradation studies, which condition most rapidly degrades butamben?

  • Neutral pH at room temperature
  • Acidic hydrolysis conditions
  • Storage under inert nitrogen
  • Low-temperature refrigeration

Correct Answer: Acidic hydrolysis conditions

Q15. What analytical impurity is a primary concern after ester hydrolysis of butamben?

  • PABA (para-aminobenzoic acid)
  • Aniline sulfonate
  • Epoxide derivatives
  • Benzoquinone

Correct Answer: PABA (para-aminobenzoic acid)

Q16. For B.Pharm formulation labs, which dosage form is most common for butamben use?

  • Oral tablets for systemic analgesia
  • Topical ointments, gels, and dental pastes for local anesthesia
  • Intravenous injections for regional block
  • Inhalation aerosols for pulmonary delivery

Correct Answer: Topical ointments, gels, and dental pastes for local anesthesia

Q17. Which preservative compatibility issue should be considered when formulating butamben topical gels?

  • Benzalkonium chloride reacts with esters to form inactive salts
  • Parabens may increase ester hydrolysis rates under acidic conditions
  • Sodium benzoate universally stabilizes esters at any pH
  • No preservatives are needed due to antimicrobial activity of butamben

Correct Answer: Parabens may increase ester hydrolysis rates under acidic conditions

Q18. What regulatory aspect is important when developing generic butamben topical products?

  • Prove systemic bioequivalence via IV studies only
  • Demonstrate pharmaceutical equivalence, stability, and in vitro release/assay data
  • No stability data are required for topical generics
  • Only color and fragrance matching are mandated

Correct Answer: Demonstrate pharmaceutical equivalence, stability, and in vitro release/assay data

Q19. Which in vitro test helps predict percutaneous delivery of butamben from a formulation?

  • Particle size analysis by laser diffraction
  • In vitro skin permeation using Franz diffusion cells
  • Acid–base titration
  • Osmolality measurement

Correct Answer: In vitro skin permeation using Franz diffusion cells

Q20. What effect does increased lipophilicity have on butamben’s local anesthetic potency and systemic absorption?

  • Decreases potency and increases systemic clearance
  • Increases membrane penetration and local potency but may increase tissue retention and risk of systemic toxicity if absorbed
  • No effect on potency or absorption
  • Prevents any absorption and eliminates systemic risks

Correct Answer: Increases membrane penetration and local potency but may increase tissue retention and risk of systemic toxicity if absorbed

Q21. Which sterilization method is least suitable for butamben-containing aqueous formulations?

  • Filtration through 0.22 µm under aseptic conditions
  • Autoclaving (moist heat) at high temperature
  • Terminal sterile filtration followed by aseptic filling
  • Using sterile ingredients and aseptic processing

Correct Answer: Autoclaving (moist heat) at high temperature

Q22. In a stability study, which parameter specifically indicates ester hydrolysis of butamben?

  • Increase in solution pH without impurities
  • Decrease in butamben assay with concurrent increase in PABA impurity
  • Change in color to green independent of assay
  • Formation of gas bubbles in the container

Correct Answer: Decrease in butamben assay with concurrent increase in PABA impurity

Q23. Which patient counseling point is important for topical butamben products?

  • Apply liberally to open wounds for faster absorption
  • Avoid application on broken or inflamed skin and report signs of allergic reaction
  • Ingest a small amount to test systemic tolerance
  • Store in direct sunlight to keep it sterile

Correct Answer: Avoid application on broken or inflamed skin and report signs of allergic reaction

Q24. Which laboratory parameter would help detect hypersensitivity caused by PABA metabolites?

  • Serum creatinine measurement
  • Patch testing or specific IgE/allergy testing for PABA
  • Complete blood count for hemolysis only
  • ECG monitoring for conduction defects

Correct Answer: Patch testing or specific IgE/allergy testing for PABA

Q25. When designing an HPLC method, which wavelength is commonly used for UV detection of butamben?

  • Visible 600 nm because butamben is highly colored
  • Typically UV range around 254–280 nm due to aromatic chromophore
  • Infrared 1500 nm for ester bonds
  • Low UV below 200 nm only

Correct Answer: Typically UV range around 254–280 nm due to aromatic chromophore

Q26. What is an appropriate approach to extend the shelf life of a butamben topical gel?

  • Formulate at strongly acidic pH to accelerate cross-linking
  • Use antioxidants, appropriate pH adjustment, and low-temperature storage
  • Increase water content without preservatives
  • Expose to intermittent light to keep microbes inactive

Correct Answer: Use antioxidants, appropriate pH adjustment, and low-temperature storage

Q27. In compatibility testing, which excipient is most likely to catalyze ester hydrolysis of butamben?

  • Non-ionic polymers like carbomer
  • Strong acids or basic salts that shift pH
  • Sorbitol as a humectant
  • Neutral oils like mineral oil

Correct Answer: Strong acids or basic salts that shift pH

Q28. For parenteral local anesthetics, ester types are generally avoided for continuous infusions due to what reason relevant to butamben?

  • Excessive protein binding prevents efficacy
  • Rapid hydrolysis and variable duration with risk of metabolite accumulation and allergic reactions
  • Their inability to block sodium channels
  • They cause immediate hemodynamic collapse

Correct Answer: Rapid hydrolysis and variable duration with risk of metabolite accumulation and allergic reactions

Q29. Which in vitro dissolution parameter is most relevant when evaluating a butamben topical ointment?

  • Quantity of API released into aqueous medium over time from the semisolid matrix
  • Tablet disintegration time in 0.1 N HCl
  • Gas chromatographic headspace profile
  • Viscosity measured at absolute zero shear only

Correct Answer: Quantity of API released into aqueous medium over time from the semisolid matrix

Q30. In forensic or quality control settings, what additional test helps confirm identity of butamben besides HPLC retention time?

  • Melting point alone
  • Mass spectrometry (MS) or LC–MS to confirm molecular ion and fragmentation
  • pH paper color matching
  • Refractive index measurement only

Correct Answer: Mass spectrometry (MS) or LC–MS to confirm molecular ion and fragmentation

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