Page 31 - Pharmaceutics-II (02-06-01 203)

Pastes

What are pastes?
▪ Pastes are basically ointments containing large proportions of solids finely dispersed in the
basis for cutaneous application
▪ They generally contain a larger proportion of solid material (such as 25%) than ointments
and therefore are stiffer
▪ Pastes can be prepared in the same manner as ointments, by direct mixing or the use of heat
to soften the base prior to incorporating the solids
▪ Pastes are less greasy and less penetrating than ointments and do not flow at body
temperature
▪ Similar to ointments, pastes form a relatively water impermeable film
▪ Unlike ointments, the film formed is opaque and therefore can be used as an effective
sunblock
▪ The increased viscosity of pharmaceutical pastes ensures that a thick film of the dosage form
is applied to the site of action, which shows excellent persistence. This property is
particularly useful if protection of an inflamed site is required, e.g. in eczema, psoriasis
▪ They are also used for their protective and water absorbing power. They are not suited for
application on hairy parts of the body
▪ Example: (Lassar's Paste)
It is used to treat and prevent diaper rash and other
minor skin irritations (e.g., burns, cuts, scrapes)

Poultices (Cataplasm)

What are poultices?
▪ They are soft semisolid, external applications applied to the skin while they are hot (applied
between 2 layers of cloth)
▪ They consist of a hydrophilic heat-retentive basis in which solid or liquid active substances
are dispersed.
▪ They are usually spread thickly on a suitable dressing and heated before application to the
skin. Used for boils, carbuncles and inflamed areas
▪ They may contain following substances,
− Absorbent: e.g. kaolin,
− Hygroscopic: e.g. glycerin,
− Anti-rheumatic: e.g. methyl salicylate,
− Bactericide: e.g. thymol, boric acid,
− flavoring agent: Peppermint oil and
− Coloring agents

Cataplasm / Poultice: What Is It? How To Do It? How To Use It?

30