Semisolid dosage forms – definition and classification MCQs With Answer

Semisolid dosage forms – definition and classification MCQs With Answer

Semisolid dosage forms are topical preparations with consistency between liquids and solids, designed for local or systemic drug delivery via skin or mucous membranes. Key types include ointments, creams (O/W and W/O), gels, pastes and plasters, each distinguished by base composition, rheology, occlusivity and drug release. Important concepts for B.Pharm students are classification of bases (oleaginous, absorption, water-removable, water-soluble), methods of preparation (fusion, levigation), evaluation (viscosity, spreadability, homogeneity, in vitro release), and stability and preservation. Mastering these topics builds competence in formulation design, percutaneous absorption, and quality control. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the correct definition of a semisolid dosage form?

• A preparation having solid particles suspended in a liquid vehicle for oral administration
• A topical formulation with intermediate consistency between liquids and solids designed for application to skin or mucous membranes
• An injectable solution intended for parenteral use
• A powdered mixture for reconstitution into an oral suspension

Correct Answer: A topical formulation with intermediate consistency between liquids and solids designed for application to skin or mucous membranes

Q2. Which of the following lists the primary classifications of semisolid dosage forms?

• Tablets, capsules, syrups, suspensions
• Ointments, creams, gels, pastes, plasters
• Injections, implants, aerosols, patches
• Suppositories, lozenges, inhalers, drops

Correct Answer: Ointments, creams, gels, pastes, plasters

Q3. How are ointment bases commonly classified?

• Hydrophilic, lipophilic, amphoteric, ionic
• Oleaginous (hydrocarbon), absorption, water-removable (emulsifiable), water-soluble
• Sublimed, crystallized, polymeric, metallic
• Buffered, unbuffered, chelated, non-chelated

Correct Answer: Oleaginous (hydrocarbon), absorption, water-removable (emulsifiable), water-soluble

Q4. Which of the following is an example of an oleaginous ointment base?

• White petrolatum (petroleum jelly)
• Polyethylene glycol ointment
• Hydrophilic ointment (contains water)
• Oil-in-water cream

Correct Answer: White petrolatum (petroleum jelly)

Q5. Which base is classified as water-soluble and commonly used when no oleaginous residues are desirable?

• Lanolin
• White petrolatum
• Polyethylene glycol ointment
• Hydrophilic petrolatum

Correct Answer: Polyethylene glycol ointment

Q6. What is the principal characteristic of an oleaginous (hydrocarbon) ointment base?

• It is water-washable and non-occlusive
• It is occlusive and prevents water loss from the skin
• It dissolves rapidly in aqueous media
• It always contains surfactants to form emulsions

Correct Answer: It is occlusive and prevents water loss from the skin

Q7. Creams are typically classified into which two major types?

• Solid and gas creams
• Oil-in-water (O/W) and water-in-oil (W/O)
• Hydrophilic and hydrophobic tablets
• Immediate and sustained release creams

Correct Answer: Oil-in-water (O/W) and water-in-oil (W/O)

Q8. Which statement best describes oil-in-water (O/W) creams compared to water-in-oil (W/O)?

• O/W creams are more occlusive and less washable than W/O
• O/W creams are less greasy and more easily washed off with water
• O/W creams cannot incorporate aqueous solutions
• O/W creams are composed solely of nonionic surfactants

Correct Answer: O/W creams are less greasy and more easily washed off with water

Q9. Which polymers are commonly used to form gel networks in pharmaceutical gels?

• Carbomers (carbopol), cellulose derivatives, and natural gums
• Simple sugars like sucrose and glucose
• Metallic salts such as magnesium stearate
• Low molecular weight alcohols only

Correct Answer: Carbomers (carbopol), cellulose derivatives, and natural gums

Q10. What does thixotropy refer to in semisolid formulations?

• An irreversible increase in viscosity with time at rest
• A reversible decrease in viscosity on standing
• A reversible decrease in viscosity on application of shear with recovery on standing
• An immediate chemical degradation upon exposure to light

Correct Answer: A reversible decrease in viscosity on application of shear with recovery on standing

Q11. Which rheological term describes a material whose viscosity decreases with increasing shear rate?

• Dilatant (shear-thickening)
• Bingham plastic (yield stress behavior)
• Pseudoplastic (shear-thinning)
• Newtonian (constant viscosity)

Correct Answer: Pseudoplastic (shear-thinning)

Q12. The spreadability test for semisolids primarily measures what property?

• The chemical stability of the active ingredient
• The ease of application and uniformity of spreading under a specified force
• The microbial content after one year
• The melting point of the base

Correct Answer: The ease of application and uniformity of spreading under a specified force

Q13. What is the primary mechanism of action of chemical penetration enhancers in topical semisolids?

• They increase systemic blood flow at application site
• They alter stratum corneum lipid structure to increase drug partitioning and diffusion
• They bind the drug and reduce its activity
• They increase formulation pH beyond physiological range only

Correct Answer: They alter stratum corneum lipid structure to increase drug partitioning and diffusion

Q14. Which preservative is commonly used in semisolid formulations to inhibit microbial growth?

• Methylparaben
• Sodium stearate
• White petrolatum
• Carbomer 940

Correct Answer: Methylparaben

Q15. Why are preservatives necessary in many semisolid dosage forms?

• To improve the color of the product
• To prevent microbial contamination and growth in products containing water
• To render the product sterile for parenteral use
• To increase the oily nature of the base

Correct Answer: To prevent microbial contamination and growth in products containing water

Q16. Which of the following is a common physical instability observed in emulsified creams?

• Phase separation (creaming or cracking)
• Complete chemical polymerization of surfactants
• Spontaneous combustion
• Conversion to tablets on standing

Correct Answer: Phase separation (creaming or cracking)

Q17. How is globule size in an emulsion cream typically determined during quality control?

• By gas chromatography
• By microscopy or laser diffraction particle sizing
• By pH titration
• By measuring melting point

Correct Answer: By microscopy or laser diffraction particle sizing

Q18. The homogeneity test for medicated semisolids assesses which attribute?

• The presence of microbial contaminants only
• The uniform distribution of drug throughout the semisolid matrix
• The boiling point of the vehicle
• The osmotic pressure of the formulation

Correct Answer: The uniform distribution of drug throughout the semisolid matrix

Q19. Which preparation technique involves triturating a powder or drug with a small amount of liquid vehicle to reduce particle size before incorporation?

• Fusion method
• Levigation
• Lyophilization
• Sublimation

Correct Answer: Levigation

Q20. What is a disadvantage of the fusion method when preparing ointments?

• It cannot produce homogeneous products
• Heat-sensitive drugs may degrade during melting
• It always produces sterile products
• It eliminates the need for preservatives

Correct Answer: Heat-sensitive drugs may degrade during melting

Q21. Which semisolid type is typically water-washable and preferred when easy removal is desired?

• Oil-in-water (O/W) creams
• Oleaginous petrolatum ointments
• Plasters that harden on exposure
• Solid tablets

Correct Answer: Oil-in-water (O/W) creams

Q22. Which ointment base is most suitable for incorporating aqueous solutions or suspensions?

• Oleaginous (white petrolatum) bases
• Absorption bases (e.g., hydrophilic petrolatum)
• Dry powder bases
• Solid polyethylene blocks

Correct Answer: Absorption bases (e.g., hydrophilic petrolatum)

Q23. What is an emulgel?

• A crystalline solid plaster for wound dressing
• A formulation that combines an emulsion with a gel to improve topical delivery and patient acceptability
• A sterile injectable emulsion for parenteral use
• An oral syrup containing suspended oil droplets

Correct Answer: A formulation that combines an emulsion with a gel to improve topical delivery and patient acceptability

Q24. Which statement correctly describes a paste as a semisolid?

• Pastes contain a high proportion of volatile solvents and are highly fluid
• Pastes are stiff, contain a high proportion of finely dispersed solids, and can absorb wound exudate
• Pastes are identical to gels but are used orally
• Pastes are only used to deliver systemic drugs via injection

Correct Answer: Pastes are stiff, contain a high proportion of finely dispersed solids, and can absorb wound exudate

Q25. What distinguishes a plaster from other semisolid forms?

• Plasters are liquid suspensions intended for oral use
• Plasters are adhesive, often solidifying or becoming less mobile after application to provide prolonged contact
• Plasters are always water-soluble gels
• Plasters are sterile ocular inserts

Correct Answer: Plasters are adhesive, often solidifying or becoming less mobile after application to provide prolonged contact

Q26. Which instrument is commonly used to measure the viscosity of semisolid formulations in the laboratory?

• pH meter
• Brookfield viscometer
• UV-visible spectrophotometer
• Atomic absorption spectrometer

Correct Answer: Brookfield viscometer

Q27. Which physicochemical properties of a drug most strongly influence its percutaneous absorption from a semisolid?

• Molecular size and lipophilicity (partition coefficient)
• Color and odor of the drug
• Melting point only
• Electrical conductivity of the container

Correct Answer: Molecular size and lipophilicity (partition coefficient)

Q28. Which of the following is NOT a semisolid dosage form?

• Ointment
• Cream
• Tablet
• Gel

Correct Answer: Tablet

Q29. What is a principal therapeutic advantage of semisolid topical preparations?

• They always provide systemic drug concentrations higher than oral dosing
• They allow localized therapy with reduced systemic side effects and enhanced patient compliance
• They are inherently sterile and require no preservatives
• They have unlimited shelf life without stability testing

Correct Answer: They allow localized therapy with reduced systemic side effects and enhanced patient compliance

Q30. Which in vitro method is commonly used to evaluate drug release from topical semisolid formulations?

• Franz diffusion cell (in vitro release/diffusion testing)
• Gas chromatographic headspace analysis only
• Direct intravenous injection
• Sterility testing using aerobic culture alone

Correct Answer: Franz diffusion cell (in vitro release/diffusion testing)

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