CLINICAL PHARMACOLOGY
Cordran is primarily effective because of its anti-inflammatory,
antipruritic, and vasoconstrictive actions.
The mechanism of the anti-inflammatory effect of topical
corticosteroids is not completely understood. Various
laboratory methods, including vasoconstrictor assays,
are used to compare and predict potencies and/or clinical
efficacies of the topical corticosteroids. There is some
evidence to suggest that a recognizable correlation exists
between vasoconstrictor potency and therapeutic efficacy
in man. Corticosteroids with anti-inflammatory activity
may stabilize cellular and lysosomal membranes. There
is also the suggestion that the effect on the membranes
of lysosomes prevents the release of proteolytic enzymes
and thus, plays a proof in reducing inflammation.
The tape serves as both a vehicle and an occlusive dressing.
Retention of insensible perspiration by the tape results
in hydration of the stratum corneum and improved diffusion
of the medication. The skin is protected from scratching,
rubbing, desiccation, and chemical irritation. The tape
acts as a mechanical splint to fissured skin. Since it
prevents removal of the medication by washing or the rubbing
action of clothing, the tape formulation provides a sustained
action.
Pharmacokinetics
The extent of percutaneous absorption of topical corticosteroids
is determined by many factors, including the vehicle,
the integrity of the epidermal barrier, and the use of
occlusive dressings.
Topical corticosteroids can be absorbed from normal intact
skin. Inflammation and/or other disease processes in the
skin increase percutaneous absorption. Occlusive dressings
substantially increase the percutaneous absorption of
topical corticosteroids. Thus, occlusive dressings may
be a valuable therapeutic adjunct for treatment of resistant
dermatoses (see DOSAGE AND ADMINISTRATION).
Once absorbed through the skin, topical corticosteroids
are handled through pharmacokinetic pathways similar to
those of systemically administered corticosteroids. Corticosteroids
are bound to plasma proteins in varying degrees. They
are metabolized primarily in the liver and then excreted
in the kidneys. Some of the topical corticosteroids and
their metabolites are also excreted into the bile.
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