GPAT–NIPER–Pharmacist exam MCQs

Semisolid Dosage Forms: Preparation, Excipients & Evaluation

1. What is the most appropriate technique for formulating an ointment that contains thermolabile drugs?

A. Fusion method
B. Incorporation method
C. Emulsification method
D. Levigation with heat

The most appropriate technique for formulating an ointment containing thermolabile drugs is

B. Incorporation method

Explanation:

Thermolabile drugs are heat-sensitive substances that may degrade when exposed to elevated temperatures. The incorporation method prepares ointments without applying heat, making it ideal for such drugs.

• The fusion method involves melting the base: unsuitable for heat-sensitive drugs.

• The emulsification method may involve heating during preparation.

• Levigation with heat is also inappropriate because heat can degrade the drug.

GPAT/NIPER Trap:

Students often confuse fusion as the standard ointment method, but the key clue here is "thermolabile," which immediately points toward a no-heat technique.

2. What is the primary purpose of levigation in the preparation of ointments?

A. Increase viscosity
B. Reduce particle size and grittiness
C. Sterilize the preparation
D. Enhance emulsification

The primary purpose of levigation in ointment preparation is the:

B. Reduce particle size and grittiness

Explanation:

Levigation is the process of triturating a powdered drug with a small amount of a suitable liquid called a levigating agent to form a smooth paste before incorporation into the ointment base.

Main objectives:

• Reduce particle size

• Prevent grittiness

• Ensure smooth and uniform dispersion in the base

GPAT/NIPER Trap:

• Levigation is not emulsification

• Levigation is not sterilization

• It mainly improves the smoothness and elegance of semisolid preparations.

3. Which levigating agent is most appropriate for use with hydrophobic ointment bases?

A. Glycerin
B. Propylene glycol
C. Mineral oil
D. Purified water

The most appropriate levigating agent for use with hydrophobic ointment bases is

C. Mineral oil

Explanation:

The levigating agent should be compatible with the ointment base.

• Hydrophobic (oleaginous) bases like petrolatum are oil-based.

• Therefore, an oil-miscible levigating agent is preferred.

• Mineral oil mixes well with oleaginous bases and helps uniformly disperse powders.

Trap:

• Glycerin and purified water are suitable for hydrophilic bases.

• Propylene glycol is more suitable for water-miscible systems.

Correct Answer: C. Mineral oil

4. When a pharmacist prepares a zinc oxide paste containing 25% solids, how does the paste generally differ from ointments?

A. Less absorptive, more greasy,
B. Less stiff, more occlusive
C. Less greasy, more absorptive,
D. Completely washable with water

Answer: C. More absorptive and less greasy

Explanation:

Pastes contain a high proportion of finely dispersed solids (usually 20–50%), such as zinc oxide or starch.

Because of this high solid content, pastes are

• Stiffer and thicker than ointments

• More absorptive (can absorb secretions)

• Less greasy compared to oleaginous ointments

• less spreadable

• less emollient

• Better suited for oozing lesions

Ointments contain less solid material and more base, so they are

• softer

• greasier

• more emollient

• easier to spread on the skin

GPAT/NIPER Trap:

• Ointments are generally more greasy and occlusive

• Pastes are protective and absorptive due to high powder content

Quick Comparison

Property Paste Ointment

Greasiness Less More

Spreadability Poor Better

Emollient action Less More

Absorptive capacity More Less

Occlusiveness Less More

5. Which of the following statements about creams is accurate?

A. They contain no emulsifying agents
B. They are semisolid emulsions
C. They are always W/O emulsions
D. They are water-free systems

Answer: B. Creams are semisolid emulsions

The correct answer is:

B. They are semisolid emulsions ✅

Explanation:

Creams are semisolid dosage forms consisting of emulsions intended for external application.

They may be:

• Oil-in-water (O/W) creams → less greasy, washable

• Water-in-oil (W/O) creams → more emollient and occlusive

Why other options are incorrect:

• A. Creams require emulsifying agents to stabilize the emulsion.

• C. Creams can be either O/W or W/O.

• D. Creams generally contain an aqueous phase.

Trap:

Students often confuse ointments with water-free systems. Creams are specifically emulsion-based semisolids.

Which of the following statements about creams is accurate?

Options: A) Creams are emulsions of oil and water. B) Creams contain higher solid content than pastes. C) Creams are always water‑free preparations. D) Creams are less spreadable than ointments.

Answer: A) Creams are emulsions of oil and water.

6. Vanishing creams are

A. W/O emulsions
B. O/W emulsions
C. Oleaginous systems
D. Suspensions

Answer: B. O/W emulsions

Explanation:

Vanishing creams are oil-in-water (O/W) emulsions that disappear rapidly after application because the water phase evaporates, leaving a thin film on the skin.

Characteristics:

• Non-greasy

• Easily washable

• Good cosmetic elegance

• Leave little residue after application

• Commonly contains stearic acid with alkali (forming soap-type emulsifier)

Trap:

Students often confuse vanishing creams with greasy cold creams.

• Vanishing cream: O/W, less greasy

• Cold cream: W/O, more greasy, forms a greasy layer on skin, and emollient

7. Which one excipient is MOST commonly preferred as a gelling agent in gels?

A. Lanolin
B. Carbomers (Carbopol)
C. Beeswax
D. Talc

Answer: B. Carbopol

The correct answer is:

B. Carbomers (Carbopol) ✅

Explanation:

Carbomers (Carbopol) are among the most commonly used gelling agents in pharmaceutical gels because they

• Produce clear gels

• Provide high viscosity at low concentration

• Have good stability

• Are compatible with many topical formulations

• Widely used synthetic polymer for hydrogel preparation

Why are other options incorrect?

• A. Lanolin: absorption base used in ointments

• C. Beeswax: stiffening agent in ointments/creams

• D. Talc: absorbent and protective powder

Trap:

Remember:

• Carbopol: gels

• Beeswax: stiffening

• Lanolin: absorption base

8. Neutralization is ESSENTIAL during Carbopol gel preparation because it

A. Increases in drug degradation
B. Produces gel consistency
C. Prevents microbial contamination of the gel
D. Gel into emulsion conversion

Answer: B. Produces gel consistency

Explanation:

Carbopol (carbomer) dispersions are initially acidic and have low viscosity. Upon neutralization with agents like:

• Triethanolamine

• Sodium hydroxide

• Potassium hydroxide

The polymer chains uncoil and swell, leading to gel formation and increased viscosity.

Trap:

Neutralization in Carbopol gels is mainly for

• viscosity development

• gel consistency

—not for antimicrobial action or emulsification.

Practice question

Question: Neutralization is essential during the preparation of Carbopol gel because it:

Options: A) Converts the polymer into its swollen form, increasing viscosity. B) Prevents microbial contamination of the gel. C) Enhances the solubility of hydrophobic drugs. D) Acts as a preservative to extend shelf life

9. Which one of the following semisolid dosage forms is MOST occlusive in nature?

A. Paste
B. O/W cream
C. Hydrogel
D. Oleaginous ointment

Answer: D. Oleaginous ointment

Explanation:

Oleaginous ointments (e.g., petrolatum-based ointments) form a hydrophobic protective film over the skin that:

• Prevents transepidermal water loss

• Enhances skin hydration

• Produces maximum occlusion

Comparison of occlusiveness:

• Oleaginous ointment → Most occlusive

• Paste → Less occlusive, more absorptive

• O/W cream → Least greasy and less occlusive

• Hydrogel → Cooling, water-rich, minimally occlusive

Trap:

Higher oil content generally means

• greater greasiness

• greater emolliency

• greater occlusiveness

Practice Question: Which of the following semisolid dosage forms is most occlusive?

Options: A) Creams B) Pastes C) Ointments D) Gels

10. The MAIN purpose of humectant use in semisolid formulations is:

A. To increase microbial growth
B. To prevent drying of the formulation
C. To reduce spreadability
D. To cause phase separation

Answer: B. Prevent formulation drying

Explanation:

Humectants are substances that retain moisture by attracting water from the surroundings. In semisolid formulations, they help:

• Prevent drying and hardening

• Maintain smooth texture

• Improve skin hydration

Common humectants:

• Glycerin

• Propylene glycol

• Sorbitol

Why are other options incorrect:

• A. Increase microbial growth: not the intended purpose

• C. Reduce spreadability: humectants often improve smoothness/spreadability

• D. Cause phase separation: undesirable effect

Trap:

Do not confuse:

• Humectants: moisture retention

• Preservatives: microbial control

• Emulsifiers: phase stabilization

11. Which combination is MOST likely used in an O/W cream as an excipient?

A. Tween 80 with cetostearyl alcohol
B. Beeswax and wool fat
C. Span 80 only
D. Petrolatum only

Answer: C. Tween 80 with cetostearyl alcohol

Explanation:

An O/W (oil-in-water) cream requires:

• A hydrophilic emulsifying agent (e.g., Tween 80)

• Often a stiffening/co-emulsifying agent (e.g., cetostearyl alcohol)

Role of components:

• Tween 80 → nonionic surfactant favoring O/W emulsions (high HLB)

• Cetostearyl alcohol → stabilizer, thickener, emollient

Why are other options incorrect:

• B. Beeswax and wool fat: More commonly associated with W/O or absorption-type bases.

• C. Span 80 only: Span 80 is lipophilic (low HLB), favoring W/O emulsions.

• D. Petrolatum only: Petrolatum alone cannot form an emulsion.

Trap:

• Tween for O/W. Hydrophilic surfactants favor O/W emulsion formation.

• Span for W/O

12. Lanolin is

A. Absorption base
B. Antioxidant
C. Preservative
D. Gelling agent

Answer: A. Absorption base

Explanation:

Lanolin (wool fat) is an absorption-type ointment base obtained from sheep wool. It can absorb significant amounts of water and is therefore useful in preparing W/O emulsions.

Characteristics of lanolin:

• Emollient

• Absorbs water

• Used in creams and ointments

• Helps incorporate aqueous solutions into oleaginous bases

Why are other options incorrect:

• B. Antioxidant: Lanolin does not primarily prevent oxidation.

• Preservative: Lanolin does not inhibit microbial growth.

• Gelling agent: Gelling agents include Carbopol and HPMC.

Trap:

Remember:

• Lanolin is an absorption base. It absorbs significant amounts of water into oleaginous systems.

• Carbopol is a gelling agent

• Parabens are preservatives

• BHA/BHT are antioxidants

13. Which one is commonly used in semisolid dosage forms as an antioxidant?

A. Talc
B. BHA
C. Sodium chloride
D. Sucrose

Answer: B. BHA

Explanation:

BHA (Butylated Hydroxyanisole) is a commonly used antioxidant in semisolid formulations to prevent oxidation of oils, fats, and drug substances.

Function of antioxidants:

• Prevent rancidity

• Improve stability

• Protect oxidation-sensitive ingredients

Other common antioxidants:

• BHT (Butylated Hydroxytoluene)

• Tocopherol (Vitamin E)

Why are other options incorrect:

• A. Talc is an absorbent/protective agent

• C. Sodium chloride is a tonicity agent/electrolyte

• D. Sucrose is a sweetening agent

Trap:

• BHA/BHT is an antioxidant. Butylated hydroxyanisole prevents oxidative degradation.

• Parabens are preservatives

• Talc is absorbent

14. Which one is MOST suitable for aqueous semisolid formulations as a preservative?

A. Zinc oxide
B. Methyl paraben
C. Cetyl alcohol
D. Hard paraffin

Answer: B. Methyl paraben

Explanation:

Methyl paraben is a widely used preservative in aqueous semisolid formulations because it is effective against microorganisms, especially fungi and some bacteria.

Why are preservatives needed?

Aqueous formulations are more susceptible to microbial contamination, so preservatives are added to improve product stability and safety.

Why are other options incorrect:

• A. Zinc oxide is a protective/astringent agent

• C. Cetyl alcohol is a stiffening/emollient agent

• D. Hard paraffin is a base component

Trap:

• Parabens → preservatives

• Cetyl alcohol → stiffener

• Paraffin → base material

15. Which semisolid dosage form is MOST suitable for oozing lesions?

A. Paste
B. Hydrocarbon base
C. W/O cream
D. Oleaginous ointment

Answer: A. Paste

Explanation:

Pastes are most suitable for oozing (weeping) lesions because they contain a high proportion of solid powders, which

• Absorb exudates and moisture

• Provide protective action

• Remain localized at the application site

Why are other options incorrect:

• The hydrocarbon base is highly occlusive, unsuitable for oozing lesions

• W/O cream is greasy and occlusive

• Oleaginous ointment traps moisture and may worsen oozing

Trap:

• Dry scaly lesions: ointments

• Oozing lesions: pastes

• Cosmetic/non-greasy use: O/W creams

16. During semisolid dosage form evaluation, spreadability reflects:

A. Sterility
B. Ease of application
C. Drug potency
D. Emulsion type

Answer: B. Ease of application

Explanation:

Spreadability is a measure of how easily a semisolid formulation spreads over the skin surface.

It reflects:

• Ease of application

• Patient comfort and compliance

• Uniform distribution of the formulation

Why are other options incorrect:

• A. Sterility is evaluated separately by sterility testing

• C. Drug potency is determined by assay

• D. Emulsion type is identified by emulsion tests

Trap:

Higher spreadability generally means

• better patient acceptability

• easier topical application

But excessively high spreadability may reduce residence time.

17. Which one is the MOST commonly used instrument for semisolids' viscosity determination?

A. Nephelometer
B. Brookfield viscometer
C. Ostwald viscometer
D. Pycnometer

Answer: B. Brookfield viscometer

Explanation:

The Brookfield viscometer is the most commonly used instrument for measuring the viscosity of semisolid dosage forms such as

• Ointments

• Creams

• Gels

• Pastes

It is especially suitable for non-Newtonian systems, which most semisolids are.

Why are other options incorrect:

• The Ostwald viscometer is mainly used for low-viscosity Newtonian liquids.

• A pycnometer is used to determine specific gravity/density.

• A nephelometer is used to measure turbidity.

Trap:

• Brookfield: viscosity of semisolids

• Pycnometer: density

• Nephelometer: turbidity

18. A cream with cracking and phase separation during storage shows failure in

A. Drug content uniformity
B. Diffusion study
C. Rheological evaluation
D. Stability evaluation

Answer: D. Stability evaluation

Explanation:

Cracking and phase separation during storage indicate physical instability of the cream formulation. These defects are detected during stability evaluation, which assesses whether the product maintains its

• appearance

• consistency

• emulsion stability

• efficacy

• safety over time

Signs of instability in creams:

• Cracking

• Creaming

• Phase separation

• Coalescence

• Change in viscosity or odor

Why are other options incorrect:

• A. Drug content uniformity checks the uniform distribution of the drug

• B. Diffusion study evaluates drug release

• C. Rheological evaluation measures flow behavior/viscosity only

Trap:

Physical defects appearing during storage almost always point toward stability problems.

19. Which one is the MOST important parameter to determine topical gel application for skin?

A. Drug release profile
B. Rheological behavior (flow properties)
C. Bloom's strength
D. pH compatibility with skin

Answer: B.

Why B is preferred over D: pH compatibility with skin

B. Rheological behavior (flow properties) directly determines application performance

It controls:

• Spreadability

• Ease of rubbing

• Extrudability from the tube

• Retention on skin

• Patient acceptability

If rheology is poor, even a skin-compatible gel may

• not spread properly,

• leak/run off,

• feel too stiff or too thin.

D. pH compatibility with skin: Mainly related to safety/irritation

pH helps ensure:

• minimal skin irritation

• drug stability

• compatibility with skin surface pH

But pH alone does not determine whether the gel applies well.

Exam Logic:

When the question asks about “skin application," examiners usually target:

• spreadability,

• flow,

• consistency,

• extrudability

All of these fall under rheology.

If the question were

"The MOST important parameter to minimize irritation or ensure skin compatibility.”

Then D (pH compatibility) would likely be correct.

20. The semisolids' primary evaluation study of in vitro diffusion is

A. Particle shape
B. Density
C. Drug release characteristics
D. Color stability

Answer: C. Drug release characteristics

Explanation:

The primary purpose of an in vitro diffusion study for semisolid dosage forms is to evaluate how the drug is released from the formulation and diffuses through a membrane.

It helps assess:

• Drug release rate

• Availability of the drug for topical action

• Formulation performance

Why are other options incorrect:

• A. Particle shape is related to microscopy/physical characterization

• B. Density is a physical property, not diffusion behavior

• D. Color stability is part of the stability/appearance evaluation

Trap:

• In vitro diffusion study: drug release

• Rheology: flow behavior

• Stability study: appearance and phase separation

21. Which base is most non-greasy and water-washable?

A. Hydrocarbon
B. Absorption
C. Oleaginous
D. PEG

Answer: D. PEG base

Explanation:

PEG (polyethylene glycol) bases, also called water-soluble bases, are

• Non-greasy

• Water-washable

• Water-miscible

• Easily removable from skin and clothing

Why are other options incorrect:

• A. Hydrocarbon base: greasy and highly occlusive

• B. Absorption base: greasy, though it can absorb water

• C. Oleaginous base: very greasy and non-washable

Trap:

• Oleaginous/Hydrocarbon bases: greasy, occlusive

• PEG bases: washable, non-greasy

22. The incorporation method is preferred:

A. When Ingredients are melted together
B. Presence of volatile substances.
C. Base has waxes that require fusion
D. High temperature stability is needed

Answer: B. Volatile substances

23. Which one factor plays the most important role in enhancing drug penetration through skin?

A. High molecular weight drug
B. Highly ionized drug
C. Occlusive base
D. Intact thick stratum corneum

Answer: C. Occlusive base

Explanation:

An occlusive base enhances drug penetration by:

• Hydrating the stratum corneum

• Softening keratin

• Increasing skin permeability

• Reducing transepidermal water loss

Hydrated skin allows better diffusion of drugs through the skin barrier.

Why are other options incorrect:

• A. High molecular weight drug: Large molecules penetrate poorly.

• B. Highly ionized drug: Unionized drugs penetrate skin better.

• Intact thick stratum corneum: A thick intact stratum corneum acts as a strong barrier to penetration.

Trap:

Factors enhancing skin penetration:

• Occlusion

• Hydration

• Low molecular weight

• Lipophilicity

• Unionized form

24. Which semisolid formulation exhibits pseudoplastic flow?

A. Increase in viscosity on shearing
B. Decrease in viscosity on shearing
C. Behave like a Newtonian fluid
D. Become solid.

Answer: B. Show decreased viscosity on shearing

Explanation:

Pseudoplastic flow is a type of shear-thinning behavior in which viscosity decreases as the shear rate increases.

This is common in many semisolid formulations, such as

• Creams

• Gels

• Suspensions

Practical significance:

• Thick at rest: prevents runoff

• Becomes less viscous during rubbing/shaking: easy application and spreading

Why are other options incorrect?

• Increase in viscosity on shearing: This is called dilatant flow (shear-thickening).

• Behave like a Newtonian fluid: Newtonian fluids have constant viscosity.

• Become solid: Not characteristic of pseudoplastic systems.

Trap:

• Pseudoplastic: shear thinning

• Dilatant: shear thickening

• Thixotropy: time-dependent recovery

25. Which one acts as BOTH an emollient and an absorption enhancer?

A. Propylene glycol
B. Prabens
C. Zinc oxide
D. Kaolin

Answer: A. Propylene glycol

Explanation:

Propylene glycol functions as both

• an emollient/humectant (helps retain moisture and soften skin)

• a penetration (absorption) enhancer by improving drug diffusion through the stratum corneum

It is widely used in topical semisolid formulations such as creams and gels.

Why are other options incorrect?

• B. Parabens: preservatives

• C. Zinc oxide: protective/astringent agent

• D. Kaolin: absorbent/protective agent

Trap:

• Propylene glycol: humectant + penetration enhancer

• Parabens: preservatives

• Kaolin/ZnO: protective absorbents

26. Which one confirms uniform distribution of medication in semisolids?

A. Rheology test
B. Diffusion test
C. Penetrometry
D. Content uniformity test

Answer: D. Drug content uniformity

Explanation:

Drug content uniformity testing confirms that the medication is evenly distributed throughout the semisolid formulation.

It ensures:

• Uniform dose delivery

• Consistent therapeutic effect

• Proper mixing during formulation

Why are other options incorrect?

• A. Rheology test evaluates flow behavior/viscosity

• B. The diffusion test evaluates drug release characteristics

• C. Penetrometry measures consistency/softness

Trap:

• Uniform distribution: Drug content uniformity

• Flow: Rheology

• Release: Diffusion study

27. Which one semisolid dosage form provides maximum residence time on the skin?

A. Lotion
B. Gel
C. Paste
D. O/W cream

Answer: C. Paste

Explanation:

Pastes provide the maximum residence time on the skin because they

• Contain a high percentage of solid particles

• Are stiff and less easily removed

• Adhere well to the application site

This allows them to remain on the skin longer than lotions, gels, or O/W creams.

Comparison:

• Lotion: least residence time, easily flows off

• Gel: moderate residence time

• O/W cream: easily spreadable and washable

• Paste: thickest and most adherent

Trap:

High solid content in pastes leads to:

• increased adhesiveness

• prolonged contact time

• better protective action

28. The role of Cetyl alcohol in creams is

A. Antioxidant
B. Preservative
C. Stiffening agent and emollient
D. Diluent

Answer: C. Stiffening agent and emollient

Explanation:

Cetyl alcohol is commonly used in creams and ointments as:

• a stiffening (thickening) agent

• an emollient

• a co-emulsifier that improves texture and stability

It helps provide:

• smooth consistency

• improved viscosity

• better skin feel

Why are other options incorrect?

• A. Antioxidant: agents like BHA/BHT perform this role

• B. Preservative: Parabens are preservatives

• D. Diluent: not its primary function

Trap:

• Cetyl alcohol: stiffener + emollient

• Parabens: preservatives

• BHA/BHT: antioxidants

29. Which one is INCORRECT regarding gels?

A. Non-greasy.
B. Cooling sensation
C. Anhydrous
D. Polymeric networks

Answer: C. Gels are always anhydrous.

Explanation:

(Hydrogels contain large quantities of water).

Most pharmaceutical gels are water-based semisolid systems containing a liquid phase entrapped within a polymeric network.

Therefore, saying gels are “anhydrous” is generally incorrect.

Correct statements about gels:

• A. Non-greasy

• B. Cooling sensation (due to evaporation of water/alcohol)

• Polymeric networks

Trap:

Students often confuse:

• Oleogels (may be non-aqueous)
  with common pharmaceutical hydrogels, which are mostly aqueous.

30. The PRIMARY reason to evaluate semisolid dosage forms' homogeneity is to detect:

A. Friability
B. Phase separation and grittiness
C. Drug dissolution in the GIT
D. Microbial growth

Answer: B. Phase separation and grittiness

Explanation:

Homogeneity evaluation of semisolid dosage forms ensures the formulation is:

• smooth

• uniform drug distribution

• free from lumps or coarse particles and

• elegant appearance

It primarily helps detect:

• Phase separation

• Grittiness

• Non-uniform mixing

Why are other options incorrect:

• A. Friability: test for tablets

• C. Drug dissolution in the GIT: relevant to oral dosage forms

• D. Microbial growth: assessed by microbial limit/preservative efficacy tests

Trap:

• Homogeneity: smoothness & uniformity

• Rheology: flow

• Diffusion study: drug release

Dr Alok Singh