Beta amino ketones – Molindone hydrochloride MCQs With Answer

Introduction

Beta amino ketones — especially Molindone hydrochloride — are important study topics for B. Pharm students focusing on medicinal chemistry and pharmacology of antipsychotics. This compound, a beta‑amino ketone derivative, is used mainly for schizophrenia and displays typical antipsychotic properties such as dopamine D2 receptor antagonism. Understanding its chemical structure, synthesis routes, hydrochloride salt properties, pharmacokinetics, metabolism, adverse effects (notably extrapyramidal symptoms), and analytical assays is essential for pharmaceutical practice. These MCQs combine chemistry, formulation, therapeutic use, and safety monitoring to deepen your knowledge and exam readiness. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What chemical class does molindone hydrochloride primarily belong to?

• Phenothiazines
• Beta-amino ketones
• Benzodiazepines
• Tricyclic antidepressants

Correct Answer: Beta-amino ketones

Q2. The hydrochloride form of molindone is used mainly to:

• Increase lipid solubility
• Enhance water solubility and stability
• Convert it into a prodrug
• Reduce potency

Correct Answer: Enhance water solubility and stability

Q3. The primary therapeutic indication for molindone hydrochloride is:

• Major depressive disorder
• Schizophrenia
• Generalized anxiety disorder
• Epilepsy

Correct Answer: Schizophrenia

Q4. The main pharmacological mechanism of molindone is:

• Selective serotonin reuptake inhibition
• GABA-A receptor agonism
• Dopamine D2 receptor antagonism
• NMDA receptor antagonism

Correct Answer: Dopamine D2 receptor antagonism

Q5. A common adverse effect seen with molindone is:

• Extrapyramidal symptoms (EPS)
• Severe hypoglycemia
• Marked hypercholesterolemia
• Renal failure

Correct Answer: Extrapyramidal symptoms (EPS)

Q6. Compared to many atypical antipsychotics, molindone is uniquely associated with:

• Significant weight gain
• Weight loss or less weight gain
• Marked hyperglycemia
• Severe QT prolongation

Correct Answer: Weight loss or less weight gain

Q7. Which synthetic transformation is commonly used to form beta‑amino ketone motifs found in molecules like molindone?

• Mannich reaction
• Friedel–Crafts acylation
• Buchwald–Hartwig amination
• Diels–Alder cycloaddition

Correct Answer: Mannich reaction

Q8. The hydrochloride salt of a drug typically affects which of the following properties?

• Chemical structure only
• Solubility, stability, and crystalline form
• Intrinsic pharmacodynamic receptor affinity
• Primary sequence of amino acids

Correct Answer: Solubility, stability, and crystalline form

Q9. Which analytical method is most suitable for quantitative assay of molindone in tablet formulations?

• High-performance liquid chromatography (HPLC)
• Gel electrophoresis
• Nuclear magnetic resonance (NMR) for quantitation
• Polarimetry

Correct Answer: High-performance liquid chromatography (HPLC)

Q10. The absorption route for molindone hydrochloride in clinical use is primarily:

• Oral
• Topical
• Inhalational
• Transdermal patch

Correct Answer: Oral

Q11. Hepatic metabolism of molindone implies that dose adjustments may be necessary in patients with:

• Severe renal impairment only
• Severe hepatic impairment
• Asthma
• Hyperthyroidism

Correct Answer: Severe hepatic impairment

Q12. Which monitoring parameter is most important during treatment with molindone?

• Electrolyte panel weekly
• Monitoring for extrapyramidal symptoms and tardive dyskinesia
• Daily serum amylase
• Routine brain MRI

Correct Answer: Monitoring for extrapyramidal symptoms and tardive dyskinesia

Q13. Molindone’s onset of antipsychotic action is typically observed:

• Within minutes of a single dose
• Over several days to weeks with continued dosing
• Only after discontinuation
• Immediately with topical application

Correct Answer: Over several days to weeks with continued dosing

Q14. A chemical property of beta‑amino ketones relevant to formulation is:

• They are strong acids with pKa < 1
• They contain both basic amine and carbonyl functional groups affecting solubility and reactivity
• They are inert and nonpolar hydrocarbons
• They are metallic complexes

Correct Answer: They contain both basic amine and carbonyl functional groups affecting solubility and reactivity

Q15. Which adverse effect is less commonly associated with molindone compared with many atypical antipsychotics?

• Extrapyramidal symptoms
• Significant metabolic syndrome (weight gain, hyperlipidemia)
• Akathisia
• Parkinsonism

Correct Answer: Significant metabolic syndrome (weight gain, hyperlipidemia)

Q16. In the lab, formation of a beta‑amino ketone intermediate can be achieved by reacting a ketone with:

• An aldehyde only
• An amine and formaldehyde in a Mannich-type process
• A carboxylic acid in a coupling reaction
• Ozone in oxidative cleavage

Correct Answer: An amine and formaldehyde in a Mannich-type process

Q17. Which interaction is clinically relevant for molindone therapy?

• Potentiation of CNS depression with alcohol
• Neutralization by antacids making it inactive
• Activation by grapefruit juice dramatically increasing potency
• No known pharmacokinetic interactions

Correct Answer: Potentiation of CNS depression with alcohol

Q18. For quality control of molindone tablets, which physicochemical test is essential?

• Radioactivity assay
• Uniformity of content
• DNA sequencing
• Enzyme-linked immunosorbent assay for antigens

Correct Answer: Uniformity of content

Q19. Which patient population requires cautious use of molindone?

• Patients with a history of extrapyramidal reactions
• Young healthy adults with no prior medication use
• Patients allergic only to penicillin
• Individuals with myopia

Correct Answer: Patients with a history of extrapyramidal reactions

Q20. A structural feature that distinguishes beta‑amino ketones is the presence of:

• An aromatic sulfonamide moiety
• An amine group beta to a carbonyl group
• A terminal alkyne
• A phosphonate ester

Correct Answer: An amine group beta to a carbonyl group

Q21. Which statement about molindone’s receptor profile is most accurate?

• It is an exclusive serotonin 5-HT1A agonist
• It primarily antagonizes dopamine receptors with variable serotonin interaction
• It is a selective beta-adrenergic blocker
• It acts as an opioid receptor agonist

Correct Answer: It primarily antagonizes dopamine receptors with variable serotonin interaction

Q22. The main route of elimination for molindone metabolites is:

• Renal excretion
• Exhalation as CO2
• Biliary excretion exclusively
• Fecal excretion only

Correct Answer: Renal excretion

Q23. In-case of acute overdose of molindone, the immediate management includes:

• Gastric lavage and supportive measures
• Immediate hemodialysis as first-line
• Administration of high-dose insulin
• Immediate thyroid hormone therapy

Correct Answer: Gastric lavage and supportive measures

Q24. Which formulation consideration is important for molindone hydrochloride tablets?

• Protection from moisture due to potential hygroscopicity
• Requirement for refrigerated storage at all times
• Containment in lightproof vials because it is photoreactive gas
• Use as an injectable emulsion only

Correct Answer: Protection from moisture due to potential hygroscopicity

Q25. Which laboratory assay can determine the molecular identity and purity of a synthesized molindone intermediate?

• NMR spectroscopy
• Urine dipstick
• Blood pressure measurement
• pH paper test

Correct Answer: NMR spectroscopy

Q26. The presence of a basic amine in beta‑amino ketones affects which pharmaceutical property most directly?

• Optical rotation
• Salt formation and aqueous solubility
• Magnetic susceptibility
• Radio-opacity

Correct Answer: Salt formation and aqueous solubility

Q27. Tardive dyskinesia risk with molindone is related to:

• Long-term dopamine receptor blockade
• Excessive cholinergic stimulation
• Serotonin agonism only
• Short-term antihistamine use

Correct Answer: Long-term dopamine receptor blockade

Q28. When teaching synthesis of beta‑amino ketones, which reagent pair is typically discussed for reductive amination?

• Aldehyde and sodium borohydride
• Alkene and ozone
• Alcohol and Grignard reagent
• Carboxylic acid and DCC

Correct Answer: Aldehyde and sodium borohydride

Q29. For regulatory documentation, which identifier is commonly used to specify the salt form of molindone?

• CAS number including the specific salt designation
• Random lot number only
• Physician’s license number
• Patient ID

Correct Answer: CAS number including the specific salt designation

Q30. Which is a common therapeutic advantage of a hydrochloride salt in oral formulations?

• Improved palatability as sweetener
• Enhanced dissolution rate in gastrointestinal fluids
• Guaranteed zero side effects
• Increased volatility for inhalation delivery

Correct Answer: Enhanced dissolution rate in gastrointestinal fluids

Q31. Which adverse cardiovascular effect should be considered with antipsychotics including molindone?

• Orthostatic hypotension
• Severe bradycardia in every patient
• Immediate myocardial infarction in all users
• No cardiovascular effects are possible

Correct Answer: Orthostatic hypotension

Q32. Analytical method development for molindone often requires selection of a suitable detection wavelength for UV analysis because the compound:

• Has no chromophores
• Contains aromatic or conjugated systems absorbing in the UV region
• Is only fluorescent and cannot be detected by UV
• Is gaseous at room temperature

Correct Answer: Contains aromatic or conjugated systems absorbing in the UV region

Q33. Which storage condition is generally recommended for many oral hydrochloride salts to maintain stability?

• Protected from moisture and stored at controlled room temperature
• Frozen at -80°C
• Left open to humid air
• Kept in direct sunlight to deactivate impurities

Correct Answer: Protected from moisture and stored at controlled room temperature

Q34. Which pharmacovigilance concern is specifically monitored for long‑term antipsychotic therapy?

• Tardive dyskinesia and other movement disorders
• Immediate allergic reaction within seconds only
• Short-term hair color changes
• Improved vision

Correct Answer: Tardive dyskinesia and other movement disorders

Q35. In medicinal chemistry, modifying the beta‑amino ketone scaffold can change:

• Only the compound’s color
• Pharmacokinetics, receptor affinity, and side‑effect profile
• Only the melting point with no biological effect
• The atomic number of constituent elements

Correct Answer: Pharmacokinetics, receptor affinity, and side‑effect profile

Q36. Which patient counseling point is appropriate for molindone therapy?

• Avoid driving or operating machinery until you know how the drug affects you
• Double the dose if one dose is missed
• Stop the drug abruptly if you feel mild dizziness
• Combine it freely with alcohol for better sleep

Correct Answer: Avoid driving or operating machinery until you know how the drug affects you

Q37. Which co-administered drug class may increase the risk of extrapyramidal symptoms when combined with molindone?

• Other dopamine antagonists or high-potency antipsychotics
• Topical emollients
• Vitamin C supplements
• Antacids only

Correct Answer: Other dopamine antagonists or high-potency antipsychotics

Q38. The IUPAC-style naming exercise for a beta‑amino ketone focuses on identifying:

• The position of the amino group relative to the carbonyl
• The chirality center only
• Number of sulfur atoms exclusively
• The radioactive isotopes present

Correct Answer: The position of the amino group relative to the carbonyl

Q39. Which laboratory parameter is not routinely required specifically for molindone but often monitored with antipsychotics?

• Fasting blood glucose and lipids for metabolic risk
• Urine culture weekly
• Complete genome sequencing monthly
• Serum ferritin daily

Correct Answer: Fasting blood glucose and lipids for metabolic risk

Q40. Which physicochemical change often accompanies conversion of a free base to its hydrochloride salt?

• Decrease in aqueous solubility
• Improved crystalline properties and increased water solubility
• Transformation into a gas
• Loss of all pharmacological activity

Correct Answer: Improved crystalline properties and increased water solubility

Q41. Which experimental technique helps determine the pKa of the amine in a beta‑amino ketone?

• Titration (potentiometric or spectrophotometric)
• Calorimetry for melting point only
• Thin-layer chromatography without standards
• Colorimetric tape test

Correct Answer: Titration (potentiometric or spectrophotometric)

Q42. Which safety issue is most relevant when handling molindone raw material in the lab?

• Use of personal protective equipment to avoid dermal exposure and inhalation
• Keeping it near open flames as it is non‑flammable
• No precautions are needed due to its benign nature
• Ensuring exposure to sunlight for activation

Correct Answer: Use of personal protective equipment to avoid dermal exposure and inhalation

Q43. Which property of molindone influences its ability to cross the blood–brain barrier?

• Lipophilicity and degree of ionization at physiological pH
• Number of sulfur atoms only
• Whether it is packaged in glass vials
• Presence of metallic impurities exclusively

Correct Answer: Lipophilicity and degree of ionization at physiological pH

Q44. When designing a stability study for molindone hydrochloride tablets, which condition is typically assessed?

• Effect of humidity and temperature on drug content over time
• Ability to change tablet color on demand
• Time to evaporate in open air
• Reactivity with gold surfaces

Correct Answer: Effect of humidity and temperature on drug content over time

Q45. Which adverse endocrine effect is less characteristic of molindone compared to some other antipsychotics?

• Hyperprolactinemia causing galactorrhea
• Severe prolactin suppression to zero
• Immediate adrenal failure
• Development of new thyroid hormones

Correct Answer: Hyperprolactinemia causing galactorrhea

Q46. Which technique would you choose to separate molindone from related organic impurities during purification?

• Column chromatography or preparative HPLC
• Simple filtration through cotton only
• Counting under a microscope
• Vortexing with inert gas

Correct Answer: Column chromatography or preparative HPLC

Q47. Which factor most influences oral bioavailability of molindone?

• First-pass hepatic metabolism and absorption characteristics
• Color of the tablet coating only
• Patient’s shoe size
• Magnetic properties of the tablets

Correct Answer: First-pass hepatic metabolism and absorption characteristics

Q48. In structure‑activity relationship (SAR) studies, modifying the amine substituent of beta‑amino ketones typically affects:

• Receptor binding affinity and pharmacokinetic properties
• Only the boiling point with no biological change
• The number of protons in the nucleus
• The electric bill of the laboratory

Correct Answer: Receptor binding affinity and pharmacokinetic properties

Q49. Which factor is important when reporting a dissolution test for molindone tablets?

• Apparatus used, medium composition, rpm and sampling times
• Name of the analyst’s favorite food
• Brand of printer used for the report
• Astrological sign of the manufacturer

Correct Answer: Apparatus used, medium composition, rpm and sampling times

Q50. For exam preparation, integrating MCQs on beta‑amino ketones and molindone helps B. Pharm students primarily by:

• Reinforcing interdisciplinary knowledge spanning chemistry, pharmacology, formulation, and safety monitoring
• Guaranteeing immediate clinical specialization without further study
• Replacing laboratory experience entirely
• Teaching surgical techniques

Correct Answer: Reinforcing interdisciplinary knowledge spanning chemistry, pharmacology, formulation, and safety monitoring

G S Sachin

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.

Mail- Sachin@pharmacyfreak.com