Creams, Ointments and gels

what is a cream defined by

semi-solid preparations intended for external use

characteristics of hydrophilic creams

oil in water

non-greasy

water washable

topical

liquid emulsion

oil droplets free moving

may coalesce

may flocculate

may move to top forming cream layer

vs creams

oil droplets are effectively immobilised in the gel phase

• no creaming

• no coalescence

• no flocculation

• structure of gel phase is important

what is the lamellar gel phase

hexagonally packed, solid-state amphiphilic molecules arranged in regularly spaced, planar bilayers

what is a canesten an example of

clotimazole cream w/w

antifungal

what is an ointment

single phase base in which solids or liquids may be dispersed

highly viscous and moisture occlusive

example of ointmetn

aciclovir eye ointment

treatment of herpes

what is a gel defined as

semi-solid system

colloidal particles may link together to form a 3D network formation

type 1 of gels

• covalently bonded

• irreversible system

• polymer is not dissolvable

• sustained release of drug

type 2 of gels

• hydrogen bonded or vander waals

• heat-reversible

examples of gelling agents

natural

• acacia

• xanthan

• alginate

clays

• bentonite

synthetic

• carbomer