PSC 4115 - Final exam - Gels/creams/ointments

Semisolid preparations for external application to skin or mucous membranes.

Ointment

Semisolid dosage forms with drug substances dissolved/dispersed in a base.

Creams

Semisolid systems of suspensions or large molecules in a liquid.

Gels

Which dosage form is a suspension, not an emulsion?

Gel

Are ointments used only for local effects?

No, they can have systemic effects

Can ointments with systemic effects affect pregnancy?

Yes, drugs can enter fetal circulation

What is the difference between topical and transdermal products?

Topical targets skin; transdermal has systemic effects

Name 3 types of non-medicated ointments.

Emollients, protective barriers, bases.

Name the four types of semisolid ointment bases.

Oleaginous, absorption, water-removable, water-soluble.

Which semisolid base has the largest emollient effect?

Oleaginous

What is an example of an oleaginous base?

Vaseline

What is the levigating agent for incorporating powder into hydrocarbon bases?

Mineral oil.

Can absorption bases be easily removed with water?

No

What type of emulsion do absorption bases form?

W/O emulsions

What are water-removable bases?

O/W emulsions that are water-washable.

Are water-removable bases dilutable with water?

Yes

Are absorption bases dilutable with water?

No

Which semisolid base is greaseless?

Water-soluble bases.

What 2 bases act as occlusive emollients?

Oleaginous, absorption

Which 2 bases are non-greasy?

Water-removable, water-soluble.

Which base can be diluted with water?

Water-removable.

Which 2 bases are non-occlusive?

Water-removable, water-soluble.

When should ointments be used?

Dry, scaly skin.

When should creams be used?

Weeping or oozing surfaces

When should lotions be used?

Intertriginous areas (skin friction).

Name the two methods for preparing ointments.

Incorporation, fusion.

What are the three types of cream bases?

W/O, O/W, water-washable.

Which cream bases can be removed with water?

O/W and water-washable bases.

What is vanishing cream?

O/W emulsion with high water content.

What are the 2 classifications of gels?

Single-phase and two-phase systems.

What is an example of a two-phase gel system?

Milk of magnesia (Mg(OH)₂ magma)

What happens to gels that thicken on standing? (2)

They form a thixotrope and must be shaken before use.

What is added to gels, creams, and ointments for transdermal drug delivery?

Penetration enhancers.

Give 5 examples of penetration enhancers.

DMSO, EtOH, PG, glycerin, urea.

Semisolid dosage forms for topical application that absorb secretions.

Paste

Why are pastes not suitable for hairy areas?

Due to their stiffness.

Adhesive masses on backing materials for prolonged contact.

Plasters

What provides prolonged drug contact: gels or plasters?

Plasters

What is the composition of the skin surface? (3)

Emulsified sebum, sweat, and epidermal cells.

How can drugs enter the skin? (2)

Through hair follicles and gland ducts.

How do drugs pass through the stratum corneum?

Diffusion

What factors affect drug absorption through the stratum corneum? (3)

Concentration, aqueous solubility, partition coefficient.

Can only aqueous-soluble drugs penetrate the stratum corneum?

No, aqueous and lipid soluble drugs can penetrate

Is the therapeutic drug concentration in the skin precisely known?

No, it’s based on qualitative measures

How would you counsel a patient on using creams, gels, or lotions? (3)

Clean area, apply thin layer, avoid bandages unless specified.

Are allergic responses to gels, creams, or ointments common?

Yes

Name 4 non-dermal uses of gels, creams, or ointments.

Eyes, ears, nose, vagina.

Which 2 dosage forms are used ophthalmically?

Sterile ointments and gels

How do drugs enter the eye? (3)

Simple diffusion through cornea, conjunctiva, sclera.

What 2 additional standards must ophthalmic ointments meet?

Sterility and metal particle tests.

Do oleaginous bases increase moisture escape?

No

What type of emulsions do absorption bases form?

W/O emulsions.

What type of emulsions do water-removable bases form?

O/W emulsions.

Can water-removable bases resemble creams?

Yes

What are the uses of transdermal ointments? (3)

Achieve topical, systemic, or circulatory drug delivery.

What is the preferred dosage form for rectal or vaginal application?

Creams

What is the difference between w/o and o/w emulsions?

W/O: oil external phase; O/W: water external phase

What is a common use for water-removable bases?

Absorbing serous discharges.

How does a water-soluble base differ from oleaginous bases? (2)

It is greaseless and completely washable.

What is the purpose of vanishing creams? (2)

High water content for moisture preservation and thin layer formation.

What does thixotropy mean in gels?

Gels thicken on standing and require shaking before use.

What is the difference between single-phase and two-phase gels?

Single-phase has uniformly dispersed macromolecules; two-phase contains floccules in a gel matrix.

What is the therapeutic use of pastes? (2)

Absorbing secretions and remaining in place after application.

Why are penetration enhancers used in transdermal drug delivery?

They increase drug absorption through the skin.

What is a common example of a penetration enhancer?

DMSO

Why must ophthalmic dosage forms be sterile?

To prevent infections and ensure safety.

What does the CAP acronym stand for in drug absorption?

Concentration, Aqueous solubility, Partition coefficient.

What is the role of bioavailability in selecting a base for semisolids? (2)

Ensures effective drug release and absorption.

What skin condition is best treated with lotions?

Intertriginous areas (where skin rubs together).

How do water-removable bases improve user experience? (2)

They are easy to wash off and non-greasy.

Why are creams preferred for vaginal and rectal applications? (2)

Ease of spread and removal.

What are the key quality control requirements for ointments? (4)

Microbial content, minimum fill, packaging, sterility.