Ceutics IV: Ointments, Creams, and Gels

semisolid advantages

hydrophilic and hydrophobic drugs

reduced undesirable effects

minimal fluctuations in drug concentration

topical

a route of administration characterized by application to the external surface of the body

transdermal

a route of administration characterized by drug product application to the skin where the drug substance passes through the dermal layer to achieve systemic effect

dermatological advantages

non-invasive

convenience and compliance

localized and systemic action

avoids first-pass

reduced systemic side effects

predictable and reversible drug delivery

dermatological disadvantages

irritation and allergic reactions

limited penetration

limited ability to adjust dosage

compliance

reduced efficacy

occlusive

a substance that promotes retention of water in the skin

emollient

an agent that softens the skin or soothes irritation in skin

humectant

a substance that causes water to be retained

protective

a substance that protects injured or exposed skin

ointment

a semisolid intended for external application to the skin

cream

a semisolid emulsion containing a drug that is either dissolved or dispersed

gel

a semisolid that has dispersions of small or large molecules in an aqueous liquid vehicle that has been thickened

lotion

a low to medium viscosity topical preparation intended for application to unbroken skin that can be used on hairy regions

paste

a semisolid that contains 25-50% solid in a conventional ointment base

ointment characteristics

local or systemic effects

< 20% water and > 50% hydrocarbons

for dry, scaly lesions

oleaginous base

a base that is water insoluble, greasy, non-washable, and forms an occlusive film

oleaginous base examples

Petrolatum

White Petrolatum

White Ointment

Yellow Ointment

Paraffin

absorption base

a base that is a w/o emulsion and is non-washable

absorption base examples

Lanolin

Modified Lanolin

Cold Cream

Hydrophilic Petrolatum

Aquaphor and Aquabase

water removing/emulsifying base

a base that is an o/w emulsion that leaves a hydrophobic film and is easily washed off

water removable/emulsifying base examples

Hydrophilic Ointment

Vanishing Cream

Dermabase

water soluble base

a base that is greaseless and uses a hydrophilic polymer

water soluble base examples

PEG Ointment

immediate release ointment

hydrophilic drug in o/w base

slow release ointment

hydrophilic drug in w/o emulsion

solid ingredient preparation

powdered form or particle size reduced

levigation

gummy ingredient preparation

pulverization by intervention

cream characteristics

application to skin or mucous membranes

> 20% water and < 50% hydrocarbons

o/w emulsion cream

for oozing wounds because they absorb water

w/o emulsion cream

for dry lesions because they reduce water loss

gel characteristics

higher water content

for external applications where ointments would be too greasy or for moist leasions

absorb large masses of fluids

single-phase gel

high MW hydrophilic polymers; molecules distributed throughout a liquid

two-phase gel

gelatinous, cross-linked precipitate; molecules uniformly dispersed throughout a liquid

paste characteristics

stiff/thick

for external application

longer retention time

occlusive, but no absorption

fingertip unit (FTU)

dosing for topical cream