#macrolide(antibiotics)

ANTIBIOTICS

Macrolide:

Macrolide antibiotics are produced by various strains of streptomyces.they have 3 common chemical characteristics.

✓ a large non-planar strain less ring.

✓ a keto group.

✓ a glycosidically linked amino sugar.

Erythromycin
Clarithromycin
Azitromycin*

✓ Erythromycin, clarithromycin & Azitromycin comes under macrolides.
✓ All Macrolide Antibiotics have Lactone structures.
✓ Usually lactone ring has 12,14 or 16 atoms in it.

STRUCTURE OF LACTONE:

Erythromycin, clarithromycin & Azitromycin are similar in structure with small differences because of their 14&15 membered ring macrolides and also in placing of glucone moiety at 3 rd and 5 th positions .

ERYTHROMYCIN:

In erythromycin Hydrogen atoms in the OH group of 3rd and 5th positions is substituted with glucone moiety .

3rd position-OCH3
• 5th position-CH3.

Erythromycin was isolated from a culture of  strptomyces erythreus.*
it is a monoacidic base.
Very bitter in taste .
White / yellow crystalline powder.
Erythromycin is insoluble in in alcohol but slightly soluble in water.
It is most effective against Gram positive cocci,streptococci....etc.

CLARITHROMYCIN:(14 membered)

•3rd position-OH
•6th position-OCH3

Chemically clarithromycin is 6-methyl-ether of Erythromycin.
It is prepared by simply methylating Erythromycin at 6-hydroxyl group.
It inhibits cytochrome P450 oxidase.
Clarithromycin occurs as white crystalline solid.
Practically insoluble in water,but sparingly soluble in alcohol &freely soluble in acetone
It is more expensive than erythromycin.

AZITROMYCIN:(15 membered)



It is a semisynthetic derivative of Erythromycin.
It is more stable than Macrolide antibiotics.
Spectrum of antimicrobial activity is similar to Erythromycin & Clarithromycin.
*It is more active against Gram neagtive bacteria& less active against Gram positive bacteria .

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#Cephalosporins-beta lactum antibiotics-pharma time

CEPHALOSPORINS Cephalosporin compounds were first isolated from cultures of Cephalosporium acremonium from a sewer in Sardinia in 1948 by Italian scientist Giuseppe Brotzu. He noticed that these cultures produced substances that were effective against Salmonella typhi, the cause of typhoid fever. Researchers at the Sir William Dunn School of Pathology at the University of Oxford isolated Cephalosporin C, which had stability to B-lactamases but was not sufficiently potent for clinical use. The cephalosporin nucleus, 7-Aminocephalosporanic acid (7-ACA), was derived from Cephalosporin C and proved to be analogous to the penicillin nucleus 6-Amino penicillanic acid. Modification of the 7-ACA side-chains resulted in the development of useful antibiotic agents and the first agent Cephalothin was launched by Eli Lilly in 1964. Mode of Action: Cephalosporins are bactericidal and have the same mode of action as other B-lactam antibiotics (such as Penicillins). Cephalosporins disrupt the sy...

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