Semisolid Dosage Forms: Ointments, Creams, and Gels

Semisolid

Not pourable; retains shape until force applied.

Ointment

Semisolid form with <20% water, >50% hydrocarbons.

Cream

Emulsion of oil and water, often used topically.

Gel

Semisolid system with a jelly-like consistency.

Paste

Thick semisolid, often used for protective barriers.

Plaster

Semisolid adhesive used for topical applications.

Lotions

Liquid preparations for topical application, often soothing.

Occlusive

Forms a barrier to retain moisture in skin.

Emollient

Softens skin or soothes irritation in membranes.

Oleaginous Base

Insoluble in water, greasy, and occlusive.

Absorption Base

Absorbs water without changing consistency significantly.

Water-removable Base

Oil-in-water emulsion, water washable and non-greasy.

Water-soluble Base

No oleaginous components, completely water washable.

Levigation

Mixing powder with liquid to reduce particle size.

Petrolatum

Semisolid hydrocarbons from petroleum, used as ointment base.

White Petrolatum

Decolorized petrolatum, considered more esthetically pleasing.

Yellow Ointment

Contains yellow wax and petrolatum; greater viscosity.

White Ointment

Contains white wax and white petrolatum; bleached.

Emulsifiable Base

Anhydrous base allowing incorporation of aqueous solutions.

Emulsion Base

W/O emulsion that allows additional aqueous solutions.

Dermabase™

O/W emulsion, soluble in water, non-greasy.

Hydrophilic Ointment USP

Water-soluble, non-occlusive, and lipid-free.

Vaseline

Common name for petrolatum, used in ointments.

Unibase®

Water-removable base, non-greasy and water washable.

Hydrophobic Barrier

Prevents moisture evaporation from skin.

Oleaginous

A base with high oil content.

Absorption Ointment

Base that can absorb water.

Water/Oil Emulsion

Emulsion with water dispersed in oil.

Oil/Water Emulsion

Emulsion with oil dispersed in water.

Water-miscible

Able to mix with water.

Ointment Bases

Foundations for ointment formulations.

Hydrophilic

Having affinity for water.

Hydrophobic

Having low affinity for water.

Spreadability

Ease of spreading the ointment.

Washability

Ability to be washed off easily.

Stability

Resistance to changes over time.

Drug Release Potential

Rate at which drug is released.

Occlusiveness

Ability to form a barrier on skin.

Uses of Ointments

Includes protectants and emollients.

Examples of Ointments

Includes Aquaphor and Eucerin.

Incorporation Method

Mixing components until uniform.

Fusion Method

Melting components together for ointment.

Levigating

Reducing particle size before mixing.

Hydrous

Containing water in the formulation.

Anhydrous

Free from water content.

Hydrolytic Degradation

Decomposition due to water interaction.

Lipophilic Drugs

Drugs with high affinity for lipids.

Absorption Bases

Bases that absorb water and drugs.

Fusion

Process of melting components to create ointments.

Medicated Ointments

Ointments containing active medicinal ingredients.

Microbial Content

Limits on microbial presence in topical applications.

Antimicrobial Preservatives

Substances like methylparaben preventing microbial growth.

Minimum Fill

Net weight or volume verification of filled containers.

Packaging Requirements

Specific containers for storage and labeling of ointments.

Viscosity

Measurement of a fluid's resistance to flow.

In Vitro Drug Release

Testing drug release from formulations in controlled conditions.

Hydrophilic Creams

Creams that attract water, easier to wash off.

Lipophilic Creams

Creams that repel water, more greasy texture.

Preparation of Creams

Involves heating lipid and aqueous phases separately.

Gels

Jellylike dispersions of particles in liquid vehicles.

Gelling Agents

Substances like carbomer that create gel structures.

Two-Phase Gel

Gel with distinct particles, thixotropic properties.

Single-Phase Gel

Homogeneous gel with no distinct particle boundaries.

Syneresis

Shrinkage of gel due to liquid expulsion.

Swelling

Increase in gel volume by liquid absorption.

Imbibition

Liquid uptake without volume increase in gel.

Bentonite Magma

5% bentonite used as a suspending agent.

Aluminum Hydroxide Gel

Gel used as an antacid, contains aluminum oxide.

Milk of Magnesia

Magnesium hydroxide suspension used as an antacid.

Pastes

Stiffer semisolids with 20-50% solid material.

Cooling Process

Stirring during cooling ensures uniform ointment consistency.

Topical Administration

Application of formulations to skin or mucous membranes.

Zinc oxide paste

Used to protect and soothe skin.

Plasters

Adhesive masses for prolonged skin contact.

Salicylic acid plaster

Used for removal of corns.

Volatiles in lotions

> 50% of lotion volume is volatile.

Viscosity of lotions

Low enough to be poured easily.

Cooling sensation

Occurs as lotion evaporates on skin.

Glycerogelatins

Plastic masses for long-term skin contact.

Composition of glycerogelatins

Contains 15% gelatin, 40% glycerin, 35% water.

Zinc gelatin

Used for treating varicose ulcers.

Semisolid formulations wheel

Visual representation of topical formulations.

Ointments

Semisolids for topical application, systemic effects.

Creams

Emulsions with varying water content.

Packaging of semisolids

Jars, tubes, or syringes for topical products.

Contamination risks

Ointments and creams can harbor bacteria.

Preservatives in semisolids

Include parabens, phenols, and sorbic acid.

Transdermal preparations

Deliver drugs through skin for systemic effects.

Ophthalmic preparations

Include ointments and gels for eye use.

Rectal preparations

Ointments, creams, and gels for rectal use.

Vaginal preparations

Include creams and creamlike foams.

Pseudomonas aeruginosa

Bacteria that can contaminate semisolids.

Staphylococcus aureus

Another bacterium posing contamination risk.