sar of aminoglycosides
Aminoglycosides antibiotics have two distinct structural characteristics. They are the amino sugar part and the hexose ring in the center, which can be 2-deoxystreptamine or streptidine.
- In this antibiotic contains two or more amino sugars joined in glycoside linkage and a centrally located substituted 1,3-diaminocyclo hexane (aminocyclitol) loop.
- Except for streptomycin, where the ring is streptidine, all aminoglycosides have a 2-deoxy streptamine ring. Two amino sugars are bound to strepidine in streptomycine.
- Two amino sugars are bound to 2-deoxy strepamine in the kanamycin and gentamycin families.
![Neomycin sulfate aminoglycosides](https://media.scbt.com/product/neomycin-sulfate-1405-10-3-_06_39_b_63910.jpg)
![aminoglycosides](https://www.researchgate.net/profile/Dr-Sumanta-Mondal/publication/321938027/figure/fig1/AS:613906460471332@1523378114928/figure-fig1_Q320.jpg)
- Amino sugars are bound to 2-deoxy streptamine in the neomycin family.
![amino sugar portion aminoglycosides](https://pharmacygyan.com/wp-content/uploads/2021/04/Screenshot-21.png)
- The C-6 and C-2 positions are targeted by bacterial inactivating enzymes, and the substitution of a methyl group at C-6 increases enzyme resistance.
- The activity is unaffected by cleavage of the 3-hydroxyl, 4-hydroxyl, or both groups.
![Aminocyclitol ring](https://pharmacygyan.com/wp-content/uploads/2021/04/image-6.png)
- While acylation (for example, amikacin) and ethylation (for example, 1-N-ethylsisomycin) do not increase activity, they do help to maintain antibacterial potency.
- Substitution on position 2 (2-hydroxylation) and substitution on position 5 (5-deoxygenation) increase bacterial inactivating enzyme system inhibition. (Derivatives of sisomicin)
![sisomicin sulfate aminoglycosides](https://pharmacygyan.com/wp-content/uploads/2021/04/image-7.png)