this contains aminoglycosides antibiotics classification with sturctures, mechanism of action, SAR, uses

1. MEDICINAL CHEMISTRY III
B. Pharmacy III/IV (Scond sem.)
Dr. K. Purna Nagasree
M.Pharm. (BITS, Pilani), Ph.D., PDF (DST, WOSA)
Associate Professor
VIGNAN INSTITUTE OF PHARMACEUTICAL
TECHNOLOGY
(Approved by PCI, AICTE New Delhi and affiliated to JNTUK)
ANISO 9001:2015, ISO 14001:2015, OHSAS 18001:2007 Certified institution, beside VSEZ, Duvvada,
Vishakapatnam-530049, Andhra Pradesh, India
2021

2. Aminoglycosides
Streptomycin, Neomycin, Kanamycin

3.  The aminoglycosides each contains one or more amino
sugars, such as glucosamine or neosamine, linked by
glycosidic linkages to a basic (amino or guanidine) six-
membered carbon ring.
 These are broadspectrum antibiotics, and in general they
have greater activity against gram-negative than gram-
positive bacteria.
Aminoglycosides

4.  The toxicity of these agents is dose-related, and therefore every
individual can get these side effects provided the dose is
sufficiently high enough.
 Because of their potential for ototoxicity and nephrotoxicity,
aminoglycosides are administered in doses based on body
weight.
 Vestibular damage, hearing loss, and tinnitus are irreversible, so
care must be taken not to achieve a sufficiently high dose.
Toxicity

5.  Concomitant administration of a cephalosporin may lead to
increased risk of nephrotoxicity, while administration with a
loop diuretic increases the risk of ototoxicity.
 These properties have limited the use
 Some can be administered for ophthalmic and topical
purposes
Toxicity

6.  Aminoglycosides work by binding to the bacterial 30S
ribosomal subunit, so causing misreading of mRNA,
leaving the bacterium unable to synthesise proteins
vital to its growth
Mechanism of action

7.  Neomycin - Streptomyces fradiae
 Streptomycin - Streptomyces griseus
 Kanamycin - Streptomyces kanamyceticus

8.  Waksman (1944) and his associates, who isolated it from a strain
of Streptomyces griseus
 The organism, S. griseus, releases the other substances, such as
hydroxystreptomycin, mannisidostreptomycin, and
cycloheximide, but do not reach up to the required
activity/potenc y level.
 resistant strains of bacteria and chrnic toxicity major drawbacks
 It is an aminoglycoside antibacterialo also used as an
antitubercular drug
Streptomycin

10.  Neomycin is a mixture of closely related epimers, neomycin B,
and C. Neomycin B differ from neomycin C by the nature of the
sugar attached terminally to D-ribose, this sugar called
neosamine.
 It is photosensitive and its main use is in the treatment of the
ear, eye, and skin infections; these include burns, wounds,
ulcer, and infected dermatoses.
Neomycin

12.  The mixture consists of three related structures, that is,
Kanamycin A, B, and C.
 The kanamycins do not possess D-ribose molecule that is present
in neomycins and paramomycins.
 kanamycins used treat to infections of the intestinal tract and to
systemic infections.
Kanamycin