Adsorbants and Protectives

ADSORBANTS AND PROTECTIVES

Adsorbants are finely powdered, inert and insoluble solids capable of binding to their surface (adsorbing) noxious and irritant substances. They are also called protectives because they afford physical protection to the skin or mucosa. Other protectives form a continuous, adherent and flexible occlusive coating on the skin. Demulcents and emollients also serve as protectives.

Magnesium/zinc stearate

They have very smooth surface—prevent friction, and are not water wettable—can be used on exuding surfaces because they allow evaporation of water and do not form a crust.

Talc

It is native hydrous magnesium silicate, which spreads easily—used in talcum/face powders. Entering raw surfaces, it can form granulomas—should not be sprinkled on wound or used for surgical gloves.

Calamine

It is native zinc carbonate tinted pink with ferric oxide. Calcined calamine is zinc oxide. It has mild astringent and antiseptic action and is a good soothing and protective agent. Used in calamine lotion along with zinc oxide and bentonite (native hydrated aluminium silicate) which have similar properties, as cosmetic, on sunburn, insect bite, urticaria and contact dermatitis.

CALACREME 5% cream, CALAMINOL 5% and CALAMYL 10% emulsion, CALAK 15% with zinc oxide 5%, bentonite 3% sodium citrate 0.5%, glycerol 5% (calamine lotion).

Starch        

It is used in dusting powders and for surgical gloves, but should not be used on exuding surfaces because it absorbs moisture, crusts on drying and encourages fermentation.

Boric acid

It is a smooth and fine powder: has mild antiseptic (see Ch. No. 65), antipruritic and deodorant actions. It is a common ingredient of prickly heat powders.

Aloe vera gel

It is a mucilaginous preparation from the fleshy leaves of Aloe vera plant with soothing and moisturising property, widely included in cosmetic and skin care products. Therapeutic claims in acne, psoriasis and many other conditions have been made.

ALOVIT: Aloe extract 10% + vit E 0.5% cream.

Polyvinyl polymer

On drying its solution forms an occlusive pelliclelike coating on abraded skin. Used as a spray on abrasions and minor cuts, it protects from dust and exposure.

HEALEX SPRAY: 2.5% + benzocaine 0.36% as aerosol wound dressing.

Feracrylum                

It is a watersoluble biodegradable polymer which forms gellike complexes on coming in contact with blood. Applied to fresh abrasions, it stops oozing of blood and protects the wound by acting as a physical barrier. A mild antiseptic action is also exerted.

SEPGARD GEL: 1% gel, to be applied as a thin film on the abrasion/wound.

Dimethicone (Dimethyl polysiloxane, Simethicone)

It is a silicone polymer—a viscous, amphiphilic liquid. It is pharmacologically inert, has water repellent and surface tension reducing properties (collapses froth). Applied to the skin, it adheres and protects it; special use— to prevent maceration and excoriation of skin due to soiling with urine (suprapubic cystostomy). Also used on bedsores, ulcers and burns.

BARRIERSF: Dimethiocone 15%, vit E 0.18% cream.

Sucralfate (topical)

This aluminium salt of sulfated sucrose used primarily as peptic ulcer protective (see p. 636), has been formulated as a topical gel. Applied on burns, bedsores, diabetic/ radiation/aphthous ulcers, excoriated skin, sores, etc. it adheres and serves to protect damaged tissue—facilitates healing.

PEPSIGARD LIGHT GEL 10% gel; to be applied on the ulcer 34 times a day.