Derzid-C Mechanism of Action

Pharmacology: Corticosteroids diffuse across cell membranes and complex with specific cytoplasmic receptors. These complexes then enter the cell nucleus, bind to DNA (chromatin) and stimulate transcription of messenger RNA (mRNA) and subsequent protein synthesis of various inhibitory enzymes responsible for the anti-inflammatory effects include inhibition of early processes eg, edema, fibrin deposition, capillary dilatation, movement of phagocytes into the area and phagocytic activities. Later processes eg, capillary production, collagen deposition and keloid formation also are inhibited by corticosteroids. The overall actions of topical corticosteroids are catabolic.
Factors that increase the clinical efficacy and potential for adverse effects of topical corticosteroids include enhancement of pharmacologic activity of the compound by altering molecular structure, increasing stratum corneum penetration of the compound and increasing bioavailability of the compound from the vehicle.
The pharmacologic activity of corticosteroids is increased by several changes in molecular structure.
Addition of 9-α-fluorine atom increases the anti-inflammatory glucocorticoid activity, but simultaneously increases undesired mineralocorticoid activity. Mineralocorticoid activity is diminished by addition of a 16-hydroxy group with longer side chains eg, acetonide, propionate or valerate increase lipophilicity and subsequently stratum corneum penetration.
Pharmacokinetics: Absorption: Absorbed systemically across the stratum corneum. Stratum corneum penetration is primarily enhanced by increasing skin hydration and/or temperature or by changes in molecular structure of the compound. Hydrating the skin with occlusive dressings eg, plastic wrap, a tight-fitting diaper or 1 covered with plastic pants, plastic tape or dermatological patches can increase corticosteroid penetration by up to 10-fold. Absorption of topical corticosteroids has been greatly increased by altering the product vehicle or the drug substance itself. Vehicles containing substances that solubilize the corticosteroid enhance absorption.
Increasing the concentration of the drug increases skin penetration but may also increase wastage of the drug.
Decreasing drug particle size has been shown to increase topical bioavailability. Increased percutaneous absorption of corticosteroids also occurs when the skin mucosa is abraded or inflamed, when body temperature is elevated with prolonged use or with extensive use. There is some systemic absorption of topical corticosteroids through the oral mucosa; absorption increases with increased potency and prolonged use.
Biotransformation: Primarily in the skin; once absorbed systemically in the liver. Corticosteroids that contain substituted 17-hydroxyl groups or that are fluorinated are resistant to local metabolism in the skin. Repeated application results in a cumulative depot effect in the skin, which may lead to a prolonged duration of action, increased side effects and increased systemic absorption.