Nhận Dạng Quốc Tế & Đặc Tính Hóa Học
Công thức hóa học
Dược Lực Học :
Gramicidin is particularly effective against gram-positive bacteria. Because the drug is highly hemolytic, it cannot be administered internally and so is used only on the skin as a lotion or ointment. It is used primarily in the treatment of infected surface wounds, and in eye, nose, and throat infections. It is normally given with two other antibiotics (neomycin and polymixin B) as an ophthalmic solution
Cơ Chế Tác Dụng :
Gramcidin D is a heterogeneous mixture of three antibiotic compounds, gramicidins A, B and C, making up 80%, 6%, and 14% respectively all of which are obtained from the soil bacterial species Bacillus brevis and called collectively gramicidin D. Gramcidins are 15 residue peptides with alternating D and L amino acids. The peptides assemble inside of the hydrophobic interior of the cellular lipid bilayer to form a β-helix. The helix itself is not long enough to span the membrane but it dimerizes to form the elongated channel needed to span the whole membrane. Gramicidin D is used primarily as a topical antibiotic and is one of the three constituents of consumer antibiotic polysporin ophthalmic solution.
Gramicidin D binds to and inserts itself into bacterial membranes (with a strong preference to gram-positive cell membranes). This results in membrane disruption and permeabilization (it acts as a channel). This leads to (i) loss of intracellular solutes (e.g., K+ and amino acids); (ii) dissipation of the transmembrane potential; (iii) inhibition of respiration; (iv) a reduction in ATP pools; and (v) inhibition of DNA, RNA, and protein synthesis, which leads to cell death.
Chỉ Định :
For treatment of skin lesions, surface wounds and eye infections