DESCRIPTION
Each gram of Plexion SCT (sodium sulfacetamide 10% and sulfur 5%) contains 100 mg of Sodium Sulfacetamide USP and 50 mg of Sulfur USP in a cream containing Purified Water USP, Kaolin USP, Glyceryl Stearate (and) PEG-100 Stearate, Witch Hazel USP, Silicon Dioxide NF, Magnesium Aluminum Silicate NF, Benzyl Alcohol NF, Water (and) Propylene Glycol (and) Quillaja Saponaria Extract, Xantham Gum NF, Sodium Thiosulfate USP, Fragrance.
Sodium sulfacetamide is a sulfonamide with antibacterial activity while sulfur acts as a keratolytic agent. Chemically sodium sulfacetamide is N-[(4-aminophenyl) sulfonyl]-acetamide, monosodium salt, monohydrate. The structural formula is:
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CLINICAL PHARMACOLOGY
The most widely accepted mechanism of action of sulfonamides is the Woods-Fildes theory which is based on the fact that sulfonamides act as competitive antagonists to para-aminobenzoic acid (PABA), an essential component for bacterial growth. While absorption through intact skin has not been determined, sodium sulfacetamide is readily absorbed from the gastrointestinal tract when taken orally and excreted in the urine, largely unchanged. The biological half-life has variously been reported as 7 to 12.8 hours. The exact mode of action of sulfur in the treatment of acne is unknown, but it has been reported that it inhibits the growth of Propionibacterium acnes and the formation of free fatty acids.
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